Higher starting point for 400 build

"...68 Pontiac 400 with #16 heads. Since I'm starting with a 350hp engine stock, could I just put in a mild cam, long tube headers with a little bit bigger diamter exhaust, and a 750cfm edelbrock, I should be in that mid 400hp range correct?..."

Don't think you can squeeze 450hp out of a 400 with a "mild cam, long tube headers with a little bit bigger diamter exhaust, and a 750cfm edelbrock," :no

For one thing, the #16 heads have too much compression for SAFE use with pump gas. Most Pontiac engine builders recommend 9.5:1 max--9.0 to 9.25:1 safer. OR, you can run a cam with lots of advertised duration, like a RA4 grind or larger, and make sure your total timing never gets high enuff to cause detonation.

You can run the #16 heads, with dish pistons, to reduce comp. But, when the comp is reduced, it's harder to make that 450hp you want. Yes, it can be done. And you can go with a stall converter and more rear end gear, to make your car "feel" like it has more power. I reckin you could call it more "seat of the pants" power.

BUT, as has been said many times, on this and other Pontiac forums, it is far easier to make 400+hp and 500ft lbs of torque, with a 455 or bigger, long stroke engine. The cheaper balanced cast crank stroker rotating assemblies are between about $1500 & $1800.

http://www.cnc-motorsports.com/eagle-b52400-pontiac-400-461-street-and-strip-balanced-rotating-assembly-10-1-1-mahle-flat-top-pistons.html

The best cheap iron heads for this stroker engine seem to be the 6x-8 heads. You can sell your #16 heads for plenty, to buy a good set of 6x cores, and pay for some of the machine work. There always seem to be plenty of 6x-8 heads for sale, in all stages and conditions, including ported and ready to bolt on.

"...it's going in my 78 Trans Am."

Keep in mind that the '68 block only has 2 motor mount bolt holes, which will require adapters to fit the 3-hole mounts in your '78 TA. Some have posted that the adapters don't work too well sometimes and require mods and fab work.

"... a 750cfm edelbrock..."

The only Edelrock carb I'd recommend is one of their Q-jets. But, I'd really rather have a PROPERLY REBUILT '76-'79 800 Q-jet, with the APT feature. Everyday & SMI have a good rep for these Q-jets. Everyday has one listed on their website, if you don't need the TH350 kickdown cable hook-up.

http://www.ebay.com/bhp/edelbrock-quadrajet

http://www.everyday-performance.com/quadrajet_carburetors.htm

http://www.everyday-performance.com/quadrajet_carburetors.htm#!/Pontiac-1976-Trans-Am-Firebird-400-Quadrajet-17056264/p/46561051/category=578011

http://www.smicarburetor.com/products/sfID1/28/sfID2/9/sfID3/100

FrankTinCA just bought one, with the TH350 kickdown cable type throttle lever, from Everyday.

http://www.firebirdnation.com/forums/topic/489889-frank-ts-68-coupe-restoration/?p=1311329

JLCustomizing said:

Is the RA4 cam going to be to much for the car if you drop the compression down? I'm sure I'd have to change my gearing to accomadate for the cam lift so I can get off the line. I wouldn't be totally against using lead additives to stay at the 10:5:1 compression ratio if that actually works.

Click to expand...

No, if the compression is up near 9.5:1, the RA4 / Rhoads lifter combo will work. :yes

And, IF you run a converter with at least 3000 rpm flash stall, you'll be able to "get off the line".

There is only one lead additive that works. And it costs so much, that it is just as cheap to run a mix of race gas. BUT, if you really wanna run high comp, the cheapest solution is to run E-85, as mentioned.

High compression and low octane pump gas just don't jive together. You either need to lower the compression or increase the octane. It's just a simple fact of life we are forced to live with.

Now, having said all that, the RA4 cam may not be the best all around cam for a 400 engine. But it is just about the smallest one I can think of that will give you 400hp. There are smaller cams that will give you better mid range power and more low end torque.

Now, if you have an extra $1000 or so to spend on a cam set-up, the correct hyd roller will make more power than the RA4 and be more streetable at the same time. Roller cams have several advantages. But that's another discussion. :smile22:

JLCustomizing said:

Ever played wit the Hurricane/Tomahawk intake from Butler Performance? I like the idea it will still fit under the shaker but have also read people say to use the stock iron from the 68-72 engines as they don't choke out as easy.

Click to expand...

I bought one of the single planes. It's a Pro Comp brand. They are all Chinese made, probably from the same origin. They sell very cheap on Ebay. Mine looks good. I bought it to put on a 455 bracket engine. Have not used it yet. The single plane is probably not as good on a 400. But they are OK on a 455. I bought a bracket car with a 455 in it. It has a Torker 2, which is a single plane. It has PLENTY of low end torque. Does not need a 2-plane to help with that.

2 advantages of the Chinese intakes, over a stock iron intake, are that they are much lighter, and do not have a heat crossover. Now, of course, if you drive a lot in cold weather, you may need the extra heat in your intake and carb. But, if not, the cooler intake and carb will produce a cooler air/fuel mixture, which is supposed to increase performance, some. And, the Chinese single planes will accept either a Q-jet or square bore carb. A Q-jet will not bolt up directly to a Torker 2. :smile22:

http://www.ebay.com/itm/Pontiac-326-350-389-400-421-428-455-Shootout-Intake-Manifold-Satin-/181603301013?fits=Make%3APontiac&hash=item2a48667695:g:Ni4AAOSwg3FUgQLF&vxp=mtr

There are lots of guys who say they hate the Chinese products and try to buy USA made stuff. If you're one of those guys, you'll have to forget about building a cheap Pontiac 400 block stroker, cause all the cheap stroker cranks and rods are made in China. Some are machined here. I suppose the only way to build a long stroke Pontiac, without Chinese parts, is to start with a 455 block and crank, then use factory cast rods, or high priced USA made rods. I think the cheapest USA rods are the Crower rods, for over $800. :shock:

http://www.summitracing.com/parts/cro-sp93419b-8?seid=srese1&gclid=Cj0KEQiA0-GxBRDWsePx0pPtp4sBEiQACuTLNhR90BlKS28v01ykvgsswTdYHuAop-oG3_r2VWbf6ZkaAiAX8P8HAQ