What is the planned use of this car? I am a bit confused as to why you are removing a perfectly good working 403.

If you can grab the 455 and it is worth grabbing get it. 455's are getting harder to come by each day.

 

Will be drivin her to the foundry during the resto, but some weekends at the local strip but stiull needs to be streetable. The car came with the new motor, and originally I had a cam and lifters ordered, and was looking for a correct set of 350 olds heads for it until I was warned off due to the webs. Personally I just worry about using that motor for anything heavy. A friend told me that they can be filled in with weld, but that sound stupid to me...Honestly, I don't really want to remove the 403, but want something that I can have some fun with at the track a time or 2 during the summer and if the 403 can be mildly hopped up safely then that'll work too! I had a 71 cutlass with a 350 rocket that ran really great...

 

OK, you mentioned destroking a '77 400. I assume you mean stroking, as in giving it MORE stroke. That will be fine IF the block is not a "557" block. If the last 3 numbers of the casting number of the block is 557, DON'T use it !

They have weak main webbing. ANY other 400 block that is a good rebuildable block will do.

You mentioned using a 421 stroke(4 inch) in a 455 block. Well, if you really want a 4" stroke you can buy a 4" stroker rotating assembly for the 400 block. And you can even buy a forged crank and wind it on up if you like higher rpm, which you seemed to indicate. I personally prefer the 4.21 or 4.25 stroke for the extra low end torque you mentioned. By having this larger stroke, you can run lower numerical rear gears.

But, by using a forged crank, you can probably still wind it up to at least 6500-7000 if you just wanted to, although I see no reason to do so. But, hey, if you just like the sound of higher rpm, go with a forged 4" stroke 400, with extra light Ross pistons and H-beam rods. OR, better yet, if you got an extra $3000 or so to put into it, start with an aftermarket Pontiac block. Alum would be even better, because it's lighter. But they are also higher.

I reckin what I'm trying to say is that there is a Pontiac combo which will be exactly what you want, IF you got the $ to build it. Also to increase the rpm and power output you can run alum heads and a solid roller cam set-up. By using an aftermarket block you can make 700+ hp and wind it on up to 7000-7500 rpm safely. It all just depends on how much you can spend on a motor.

You are obviously not aware of all the latest in Pontiac engine technology. So I'll post the links to a few sites which show several different combos, using both stock and aftermarket blocks. Now most of these are high end builds, but similar engines can be built cheaper with the right builder.

http://www.krepower....t%20Engines.htm

http://www.jbp-ponti...rate_motor.html

http://www.jbp-ponti.../474_cu_in.html

http://tinindianperf...ombinations.htm

http://www.sandovalp.../#!engines/c66t

Here's a balanced 4" stoker assembly, to build a stroker with your non "557" 400 block. The forged crank, Ross piston, H-beam rod combo should do what you want.

http://www.jbp-ponti...es.html#433-446

 

But, if those motors are above your budget, there is still a way to get over 400hp and 500ft lbs of torque, for around $5000.

Here's a 4.25 stroke 400 short block, with H-beams and a cast crank. Or for about $350 you can upgrade to a forged crank.

http://lenwilliamsau...hort_Block.html

You can go with iron heads, like on this 455.

http://lenwilliamsau...Long_Block.html

Or you can go with alum heads like on this 400.

http://lenwilliamsau...rock_Heads.html

If you go with alum heads, you can buy Edlebrock D-port heads, which have the heat risers in them, so that if your intake manifold has the heat crossover, the motor will warm the intake and carb for cold weather driving, if you'll be doing any.

http://www.summitrac...6mMkaAoPP8P8HAQ

Or if you will not be doing any cold weather driving, you can use KRE D-ports. SD is one of the best Pontiac head shops around. They can fix you up with any alum head combo you want.

http://www.sdperform...p?categoryID=49

http://www.krepower....der%20Heads.htm

Hey, some of this info should at least give you some ideas for your motor. If we can help you with any other details, we'll be glad to.

 

Wow, you called it correctly about me not knowing about the latest pontiac technology! It's not that I necessarily want to rev the motor, just not too crazy about having to cringe when or if it happens. Actually, the stroke would be shorter than stock in the application that I was referring to, -- like in a more HP oriented motor versus torque. But after reading your posts and looking at the possibilities, running a lower rear gear with more torque sounds like a better option... Truthfully, its been over 20 years since I actually owned a classic car, and I still can't get over how expensive everything is nowadays... I bought the '71 cutlass for like 300 bucks in 1987... ha ha. Thank you much!

 

...I still can't get over how expensive everything is nowadays...

Hey, tell me about it ! I use to sell Hedman headers for a '68 Bird, for $69.95 and make a small profit. Now they cost over $250.

And I use to buy Birds and Goats with 400 engines and TH400 trannys, with decent bodies for $300 each. Hey my brand new RA3 '69 GTO only cost about $3400. And I bought several one ton trucks, to get our cars to the track, for about $4000 a piece, brand new. Yeah, things have really changed !

 

OK, you may not be aware of this, but a long stroke Pontiac has enuff torque to wipe out the outer sprag race in a TH350 tranny. You mentioned that you have a newly built pci TH350 (I Googled pci transmission and didn't come up with a tranny shop ?) . But that doesn't mean it will hold up to Pontiac torque. I learned this the hard way. I bought a TH350 that had been running just fine in an 11 sec Nova. But that Nova had a sbc motor with very little low end torque. When I ran it in my bracket car behind a 455, the outer race broke on the first 1-2 shift.

Somebody told me that all I needed was a HD heat treated outer race. So, I bought one from TCI. I thought that would fix it. WRONG ! It also broke on the first 1-2 shift. Now if you have hard street tires on it when you shift to 2nd, you'll probably be alright. But if you are at the track and have sticky tires on it, Pontiac torque could do it in.

But, nowadays there are HD parts that are said to make the TH350 live. They consist of a 36 element sprag, drum and race assembly. This Ebay link shows some of these assemblies, and a couple of trannys. Or you can just google TH350 with 36 element sprag, and find lots of good info on the subject.

http://www.ebay.com/...0&_sacat=171114

https://www.google.c...element%20sprag

 

"a 327 block along with the 283's crank and rods that would wind up better than any engine that I had ever heard"

What you had there was a '302'. Yes, with the right stuff, they will wind up as faster than about any production engine. But the good stuff is a 350/4bolt with forged 302 crank/rods/pistons

A big Pontiac may not spin up as fast, but will pound a mousemotor senseless with torque.

High torque is great on the street, and easier on the wallet at the track.

More consistent, easier to drive, builds more confidence for the driver.

Plenty of stuff to think over--haha

 

Surely appreciate all of the great advice fellas! My budget for the motor is around 3400 cash and MAYBE another grand credit if needed, but that doesn't mean that it has to be spent. right? I hadn't even considered the tranny bellhousing matching issued.. and I must admit that I did not buy the tranny, although it's easy to see that it's new. The seller may have mispoke the company name (was in kansas city) as he was selling the Trans Am for a neighbor. I do appreciate the heads up though about the risks of torque damage. I reckon that I may need to research clearances,etc... for a turbo 400 or possibly a newer metric overdrive tranny... Really rather have a powerglide though, especially with the poncho motors having the torque advantages. Still can't shake the need to attempt to get the poncho's to have the balance between the tranny breaking torque and the high end horsies... ha ha. Maybe I'll just get that Granhdville and jerk the motor out, put it on a engine stand and see what happens while using the current motor and tranny to drive on...? A friend here locally has sent parts to BTR and had them machined for a racing application and they worked very well. Maybe just getting the very best balancing,porting, and polishing will help... Thanks y'all!

 

My budget for the motor is around 3400 cash and MAYBE another grand credit if needed, ... Maybe I'll just get that Granhdville and jerk the motor out, put it on a engine stand...

Most of the 455's I bought came from Grandvilles. The heads are low comp, but the block and crank are good to at least 5500 rpm safely, without high $ parts. A set of 6x heads on the 455 will make a nice engine. But, can you build it for $3400 ? Well, I reckin that depends on the machine shop charges.

The parts can be figured fairly close. And since your budget is low, let's figure on using the heads off the 455 IF they have screw-in rocker arm studs. Pontiac started using screw-in studs in all their motors sometime in 1973. Before that, many had press-in studs, which can come out when running a larger than stock cam for high performance use. The cost to install screw-in studs is too high. If the 455 heads have press-in studs, it will be better to buy some 5c or 6x heads which already have screw-in studs, and smaller combustion chambers for more compression.

Pistons: SP L2359NF030 -- $312 --Summit

Rings: SP E-300K30 -- $85 -- Sum

Rods: RPM 5140 forged -- $243 -- Competition Products

Rod, main and cam brgs: -- $160

Freeze plugs & 3/8 NPT pipe plugs for the oil galleries: ? Machine shop will supply these items. Have them drill one pipe plug with a .020-.030 hole to squirt oil on the dist and cam gears. They will have to tap most of the holes for the plugs.

Oil pump & driveshaft: Melling M54DS & IS-54A -- $60

Cam & lifters: Summit 2801 or 2802 kit -- $115

Timing set: Cloyes C-3007K -- $25 --Ebay

New balancer: Powerbond -- PB-1056N -- $78 -- Ebay

Stainless one piece valves: Ferrea brand -- $175 -- Ebay

Roller tip rockers, poly-locks, BBC studs: $200 -- optional -- stock rockers will work.

Stock length hardened pushrods: CC -- $30 -- Summit

HEI dist: -- $100 - $300 to either put new parts on a used one or buy a decent new one.

Gaskets: Fel-Pro 1016 head gaskets and other gaskets -- $150

Headers: Hedman 28150 -- $260 -- Ebay, Summit

Oil filter: NAPA Gold 1258 or Wix 51258 -- $6 - $8

Hey, I'm sure I forgot some stuff, but this should get you in the ball park. Don't forget, you'll need a machine shop that knows Pontiac motors.

 

http://www.pontiacpower.com/For%20Sale.htm

Was considering a set of #16 heaDS if yall think itll be better... They have great specs and would bump up the compression.

 

http://www.pontiacpo.../For%20Sale.htm

Was considering a set of #16 heaDS if yall think itll be better... They have great specs and would bump up the compression.

1st, about "Rock & Roll ". That guy has been sort of ostracized by most of the Pontiac community. That's all I'll say about it. You can check out the name Bruce Fulper, and decide for yourself.

Then, about the #16 heads. Yeah, they were good heads, along with #12, #13, #48, #62, #64 and a few others. Those are the numbers of the heads we raced. BUT, they are high compression heads.

They were rated about 10.5:1 on a 400. So all these heads, except the #64's, on a 455, will make probably 11 or 12:1 CR.

This will not work with pump gas !

You'd have to run at least 100 octane gas. That would be somewhere around a 50/50 mix of 108 racing gas and 92 octane pump gas. And around here, racing gas is over $10 a gal. And, those old heads did not have the hardened valve seats needed for use with unleaded gas. The 6x heads came with hardened seats from the factory.

The only alternative I know of to allow you to run high comp today is to have hardened valve seat inserts installed in the heads, by somebody who really knows what they are doing, then run E-85 fuel. But that requires some changes, and that you be close to a good cheap source of E-85.

Now, with alum heads you can run 10:1 CR or a little more, with no problems. But most agree that 9.5:1 is about tops for iron heads on pump gas.

 

True, I certainly do not want any more than 9.5 or 10 to 1 compression as that will make plenty of power on 93 to 95 octane on pump gas. Using a lead additive isn't a very big deal but having to run high octane gas is... like you said very expensive. I can say that ya know the poncho motors very well, all the little nuances and tricks and I hadn't even considered the octane yet, just parts durability. I reckon that is why I am considering all the factors before making any decisions. Man, it'd sure be so simple to just stick a cam and lifters in the 403, along with porting and polishing a set of olds 350 heads... the intake, headers, and carb are already there as well as the bottom end. Dang main webbing... It's too bad there isn't any way to fill them with material or strengthen them without a girdle. Truthfully, the main reason that I wanted the high RPM capability was to be able to run the current gearing with the T350 that unfortunately doesn't have a 4th gear... To simplify things, it just might be better and cheaper to just jerk the 455 out of the grandville, and just have those heads done and milled to increase compression slightly. Using the T400 out of her should provide a bit more durability. That would allow me to return to the stock rear gearing that came in the car as the torque would be very sufficient to get her going. Boy it seemed so much easier in the late 80's... ha ha. I reckon that's partly because you could get the "turbo blue" gas at united right out of the pump at 116 octane I believe to mix with the regular unleadeed... Course it could be that I am just getting old..? Thank you again and also for the heads up on rock n roll.

 

Yeah, nothing is easy or cheap any more. Here's another example: If you just use the 455 and shave the heads for more comp, it will probably just cause the old shortblock to start smoking. If it is original, the pistons and rings are 40 years old.(don't recall you listing a year model for the GV) They may not stand any more comp. Also, the cam is probably going flat, and the timing chain is probably real loose.

At the VERY least, it probably needs rings, brgs, cam, lifters, timing set, and a new oil pump and shaft. We use to do stuff like that. But 455's are so rare now, most do a complete rebuild with forged pistons and all new stuff.

And then, there is the TH400 you mentioned. It is a long tail model. The 2nd gen Birds that came with a TH400 had the short tail. So, to use it in the Bird, you'll have to rig a crossmember that will work, AND shorten the driveshaft, AND change out the front slip yoke. And it still doesn't have a 34 elemnt sprag in it. And it may be wore out. I think it would be cheaper to use a GOOD TH350. Hey, if yours shifts good, you can start with that. Then, before you strap on any sticky tires and go to the track, you can get a HD model or have yours beefed up.

 

That is another good idea, and I was looking up tranny stuff about the 350's earlier... With it being basically brand new-it wouldn't have to be completely rebuilt, just beefed up like you stated. (again i'm going off of research as I know nothing about those complicated trannys) I would surely do the bottom end of the 455, pricing a rotating kit hasn't been too bad and I wouldn't have to buy heads so I could spend that cash on a cam kit or the machining work. I think that I have decided on driving the 403 this winter (just to the foundry to get the body and interior done as I can use the equipment there) While bolting the machined block to an engine stand at home to build up slowly over the winter. That way, I can invest what I have in the machining first, having that all done along with the crank- and go from there. Taking my time will also give me a chance to get brushed up on all the differences that the Ponchos (and technology) differences... Things like the weep hole, rope style main seals, and the looong strokes of these motors are just some of the differences that I need to educate myself on. Another thing that I hadn't realized is the TH350's aren't as durable as I had thought. The one in my '71 was great, but only had that 350 rocket in front of it, which I'm sure is in another zip code in reguards to torque output. Oh and the 455 is a '71 as well if that is better than a later year...? I do remember that as the 70's went on, the power went down. Thanks for all of the great direction!

 

OK, if the 455 is a '71, it should have either #98 heads(that's bad) or #66 heads(that's good). I think the #98 heads came on 2 barrel engines. They had small valves and press-in rocker arm studs. I have one of these that came out of a '71 Safari wagon. The #66 heads came on 4 barrel engines. They have big 2.11 intake valves and 1.77 exhaust, as well as screw-in studs.

The small valves are not a problem, as they can be changed out. But it will cost quite a bit to install screw-in studs. The machine shop has to either tap the holes and use ARP studs, made for this purpose, which cost nearly a hundred bucks, plus machining cost, OR they have to install heli-coils in the holes so you can use either stock Pontiac studs or BBC studs. I haven't seen a price to have this done, but I'm guessing that doing it either way will cost over $200.

That's why I said, it would be better to find some usable 5c or 6x heads, and have them worked. Another reason not to use either of the '71 heads is that the valve seats were not hardened. With unleaded gas, you need hardened valve seats. A competent Pontiac machine shop can install hardened press-in seats into the early heads. But you are adding to the cost of the finished heads. So, if you start with the later heads, you save the cost of seats and studs, plus you get a lot more comp. The 455 heads have 114cc chambers.

The 6x-8 heads have only about 100cc. The 6x-4's have about 94cc .They came on LOTS of 350's and 400's from '75-'79. So they are not real expensive, and are usually easy to find. They are often for sale on Ebay and several Pontiac sites, but It's much better to find them locally, cause the shipping cost on the heavy heads is so high.

http://www.classicpo...Page=V8HeadInfo

http://www.wallaceracing.com/head1.htm

The ready to run heads will cost several hundred bucks any way you go. So, another thing for you to consider, is whether to find some rebuildable 6x heads, OR, since you have decided to drive the car with the 403 for now, and build the motor slowly, you may wanna wait on the heads and see if your finances can stand some alum heads by the time you are ready to put it all together, At the current prices, alum heads will cost somewhere between $2300-$2600. I will just take a wild shot and say that the total cost of the 6x heads, including the core price, parts and machining cost will probably be around $600-$800. Or, the big shops sell ported versions for $1700-$1900.

http://www.jbp-pontiac.com/products/cylinder_heads/cylinder_head_labor.html

http://www.sdperformance.com/viewProduct.php?productID=43

The only place I know where you might be able to buy some non ported 6x heads for a reasonable price is Len Williams. I don't know if he sells the heads separately or not. He does sell the shortblocks without heads.

http://lenwilliamsautomachine.com/455_Short_Block.html

http://lenwilliamsautomachine.com/455_Long_Block.html

 

Another thing you mentioned is the rope style rear main seal. These are still available and used by many. The only good quality one is made by a co called Best Gasket.

http://www.ebay.com/itm/1968-1976-Pontiac-V8-428-455-Narrow-Groove-Rear-Main-Oil-Seal-Gasket-Set-/300956055441?_trksid=p2054897.l4275

But many Pontiac engine builders today use the two piece Viton seals, which are sold by several vendors. There is available now a one piece Viton seal for the 3" main blocks, like the 400's. But they haven't yet come out with a 3.25" version to fit the 455 blocks. So, the two piece Viton is the best available at this time for a 455. For me, that's just one more advantage of using a 400 block instead of a 455 block.

http://www.bopengineering.com/beltdrive_acc_topend.shtml

http://tinindianperformance.com/Pontiac%20Viton%20Rear%20Main%20Seals.htm

 

Another thing you mentioned is the rope style rear main seal. These are still available and used by many. The only good quality one is made by a co called Best Gasket.

http://www.ebay.com/...=p2054897.l4275

But many Pontiac engine builders today use the two piece Viton seals, which are sold by several vendors. There is available now a one piece Viton seal for the 3" main blocks, like the 400's. But they haven't yet come out with a 3.25" version to fit the 455 blocks. So, the two piece Viton is the best available at this time for a 455. For me, that's just one more advantage of using a 400 block instead of a 455 block.

http://www.bopengine...cc_topend.shtml

http://tinindianperf...ain%20Seals.htm

I have heard two different theories on those teflon coated rope seals, one being leaving a very small area for "crush" and another that installs them a tad offset as to not have the seams in the same spot as the main cap seams. I have also heard of the viton, but am a bit apprehensive as I have read about fakes, low quality copies, and the like and really am unsure of the longevity. It does amaze me though that there isn't a u cup or other type from another application that will cross reference to pontiac...? The Ford 460 (with a tad bit of modding) will fit olds, and I cant remember the others but I know there are a few. I think that I will feel more comfortable with the rope type for longevity. Although I have read about others building up the 403 olds some, It bugs me that the motor and tranny are both new and I can't really hop up the motor any without worrying whenever the RPM hits 5 grand... Oh well, at least she will have a true Poncho heartbeat rather than a transplant right? I like the 400, but it's just hard to turn down the 455, especially when I know the torque possibilities and how clean the motor is internally. (he changed the oil religiously after a ring/gasket/bearing kit 5 years ago)

 

Steve here are sum 6X heads on ebay they don' say whether they 8 or 4s

http://www.ebay.com/itm/1971-78-6X-pontiac-heads-gto-lemans-bonneville-grand-prix-norwalk-delivery-free-/271596941895?pt=Motors_Car_Truck_Parts_Accessories&hash=item3f3c707247&vxp=mtr

 

Steve here are sum 6X heads on ebay they don' say whether they 8 or 4s

http://www.ebay.com/...c707247&vxp=mtr

This guy says these heads have press-in studs. All 6x heads had screw-in studs.

In fact, all Pontiac heads beginning in late '73 and after had screw-in studs. Using the close-up deal, you can even see part of the hex part of several of the screw-in studs on these heads. So, I don't have a clue why he said they have press-ins.

I haven't seen two iron heads shipped for $80 in recent years. If these heads are truly ready to "bolt on", they are a good price. But they probably have stock valves which are almost 40 years old, and who knows if the shop that did the valve job even installed new bronze guides or not. I would use these for cores only, and have a GOOD shop fix 'em with one piece SS valves, bronze guides and good seals. The failure of one stock valve could wipe out a whole motor.

 

BOP has a new one piece rear main seal for the 3in main engine.Have used them on my last two builds with no issue.Tom

 

OK, I didn't know about the ring job 5 years ago. If it's for a good price, stick that sucker in there and see if you like it. Hey, it might make all the power you want for now. And with the low comp your TH350 may even live , especially with street tires. The low comp 455's didn't make as much power as the 1st ones. In 1970 they had about 10:1 CR with the #64 heads. I was given one of these out of a 1970 GTO. It was my 1st 455. It is the motor that broke the int sprag in 2 different TH400's including one TCI full competition reverse pattern manual valve body model. But the name didn't help the stock 16 element sprag they failed to swap for a 34 element.

And this same 455 also wiped out an 8.2" small 10 bolt rear end--broke the pinion shaft.

I also found out that because of the low end torque of this 455, 9" slicks were almost useless on the tracks we were running. I wound up with 13 x 30 slicks to hook it up. But once I got all that torque harnessed it ran mid 12's and won lots of races. We raced it for 3 seasons--probably over a thousand passes down the 1/4 mile. No problems, once everything was beefed up for the extra torque.

Now, about the rear seal. Back when I started building my own 455's, there was a co called H-O Racing Specialties. They were the biggest name in Pontiac performance at the time. They sold a two piece rear seal, which I later discovered was made for a 500 Caddy engine, I believe. I used those in every 455 I built and never had a problem with any of 'em. They were neoprene. Those of today are Viton, which is supposed to be better. Also discovered that the 34 element TH400 sprags we used back then were actually a GM part which they used behind those 500 Caddy engines. I'm guessing that they made 500ft lbs of torque also.

The Best Gasket rope seals are OK. And it is recommended to leave just a small amount at the ends. The kit includes a cutter and a small shim to cut it off at the correct location. But, as you'll see from the two links, there are better cutting tools.

https://www.youtube....h?v=1qXo9pW6nEo

http://www.hemmings..../hmn_tips2.html

 

I keep hearing how weak the 350 turbo is. I know the 400 turbo is stronger but I have been running a 350 behind my 455 for close to 3 years now. Been to the track maybe 10 times. Always runs 7.50s or 7.60s in the 1/8th using Mickey Thompson 275/60/15 drag radials. Ran the quarter mile couple weeks ago and ran my best time ever. 11.80 @ 114 mph. Nothing special in this trans. Just a good rebuild with a shift kit by a local mechanic. I run a 3000 rpm stall 10" convertor. I think the convertor helps the trans live because it did soften the 1st to 2nd shift over the stock one. I drive the car on the street once or twice a week usually on street tires. When this trans goes I will probably go with something different then but this is what I had when engine was built and it has done good so far.

 

Consider yourself either lucky or blessed. I broke one stock sprag outer race and one TCI heat treated race, on two consecutive nights at the track. Also broke two TH400 sprags, and a Powerglide, all with 12 sec 455's. These motors had about 500ft lbs of torque. Do an online search and see what parts the tranny vendors say are required to withstand this kind of torque. Most agree it takes a 36 element sprag and drum assembly.

http://www.bobistheo...r=776202&page=2

http://www.nastyz28....ead.php?t=84090

http://www.ebay.com/sch/i.html?_odkw=&_fln=1&_ssov=1&_osacat=171114&_qfkw=1&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.X36+element+sprag+for+TH350&_nkw=36+element+sprag+for+TH350&_sacat=171114

 

i would rather stroke a pontiac than de stroke one more cubes equals more power and tq easier dont need to rev high if you have the tq to mave the mass