[UntrustedAlly]

Hello everyone.

I have a 1977 Pontiac Catalina with the 5.7 350 Pontiac engine. I plan on getting a 1979 Pontiac Firebird with a 305 to restore. I plan on swapping the engines. I have access to the equipment and such but I'm wondering what this will all entail. Both engines run and work fine. I assume I'd have to do a transmission swap due to switching from a Chevy to a Pontiac. I am new to this, but I have several experienced people I can work with that can help. Any and all advice would be great

 

[ponyakr]

Welcome to FBN ! :welcome500:

Yeah, there are quite a few of us old Pontiac freaks here, that would love to help you all we can, to get that Chevy engine out and put a Pontiac in !!!! :yes

You'll need some motor mounts that came in a '75 up Firebird. It's the kind of mounts that have the rubber part in the "clam shell" that bolts to the frame. Then, a 3-bolt all metal mount bolts to the block. This mount slips down over the clam shell, and a long bolt goes thru both parts.

The Cat may have mounts that LOOK the same. BUT, I've tried to use mounts that LOOKED the same but were not. :no I have read that only the 301-455 Bird mounts will work in a Bird. The big car mounts, position the engine too high in the frame. Now, the clam shells may be the same, including for the 305. But, they will probably need to be moved to some different holes in the frame.

I've got some pics and part numbers for the correct block mounts. The left and right block mounts are different. The correct part numbers are 496892 & 496893, stamped right on the mounts. As these have become harder to find, lots of guys are advertising them on Ebay for ridiculous prices, some over $150.

http://www.ebay.com/itm/1978-Pontiac-Trans-Am-400-Engine-Motor-Mounts-496892-496893-1975-1981-455-/381512317280?hash=item58d3e7f960:g:n9QAAOSwX~dWjaEU&vxp=mtr

But, there are still some nice guys, in the Pontiac hobby, who will sell parts for a reasonable price.

On the Summit site, the clam shell frame mounts are shown to be the same for Pontiac, sbc, and 403 Olds engines. The cheap mounts have a 2387 part number, and are sold under several brand names. Westar & Anchor are 2 of 'em. :smile22:

http://www.summitracing.com/parts/ani-2387/applications/year/1979/make/pontiac/model/firebird

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2051541.m570.l1313.TR0.TRC0.H0.X2387+engine+mounts.TRS0&_nkw=2387+engine+mounts&_sacat=6000

 

[UntrustedAlly]

Thank you for the welcome

But yes, I was mostly concerned with the mounting differences between the two engines. I don't know how they differ and if they do. If they are different, how could I remedy this?

 

[UntrustedAlly]

Alright, so I need these? http://www.ebay.com/itm/75-81-Pontiac-Firebird-400-455-Motor-Mount-Brackets-Engine-Side-496892-496893-/191493622197

Correct model and such?

Edit: Pricing isn't bad, this seems perfect: http://www.ebay.com/itm/1978-Pontiac-Trans-Am-400-Engine-Motor-Mounts-496892-496893-1975-1981-455-/381512317280?hash=item58d3e7f960:g:n9QAAOSwX~dWjaEU&vxp=mtr

Second Edit: What about the transmissions? Will I need to swap them aswell? Do they need different mounts?

 

[ponyakr]

OK, you can buy or make a simple adapter plate, which will allow you to bolt the Chevy trans up to the Pontiac engine. There are lots of these available, for less than $100. I'll look up a few and post links to some.

http://www.jegs.com/i/JEGS-Performance-Products/555/60172/10002/-1?parentProductId=

http://www.summitracing.com/parts/tci-230001?seid=srese1&gclid=Cj0KEQiAn8i0BRDur-HV1PCTy4UBEiQAPuFr9Kl2UowuCl1ii8X7qSZhVp_cXNKdF_w1n8cSgYz_lnEaApEk8P8HAQ

http://www.amazon.com/TCI-230001-Adapter/dp/B000NZYMU6

http://www.amazon.com/Trans-Dapt-0061-Chevy-350-400/dp/B000CQ47LU

"...Alright, so I need these? http://www.ebay.com/...3-/191493622197..."

Yep. But, I'd check the number on the 350 mounts, to be sure they are not the same. If you have to buy, I'd post it on this and other Pontiac sites. You can probably save a few bucks that way. :yes

http://forums.maxperformanceinc.com/forums/forumdisplay.php?f=446

"...Do they need different mounts?..."

I think the trans can stay in the same place. If not, it should be close enuff to maybe just slot the trans mount holes in the crossmember, to allow the trans to move either forward or backward, slightly. :smile22:

 

[UntrustedAlly]

That's a much better option than swapping the transmissions as well. What essential parts do you think I probably won't be able to switch over?

Aside from the mounts possibly, of course.

 

[ponyakr]

"...What essential parts do you think I probably won't be able to switch over?.."

Well, let's see:

Brackets, pulleys, starter, exhaust manifolds or headers. May need a power steering pump off a Bird which had a 350-455 Pontiac engine. Don't know if you can use the Chevy pump, with Pontiac brackets, or not ? Maybe some of the guys who have made the switch can chime in, with the details.

The starter and fuel pump are on opposite sides from the sbc. So. you'll have some wiring and plumbing mods to make. Pontiac engines seem to produce more heat than sbc's. So, you'll probably need a better radiator, like an alum American Eagle, with 2 rows of 1 inch wide tubes. And you'll need to use a good shroud, with a good fan, which is partially in and partially out of the shroud. You also need a good water pump, with the divider plate-to-pump impeller clearance brought down to a minimum. A large gap between the plate and impeller will cause overheating.

 

[UntrustedAlly]

Is transferring the radiator from the Catalina to the Firebird not an option? I intended to transfer most of the engine dependent stuff like that as well

 

[ponyakr]

I'm sorry, but I have no idea what size that radiator is. I reckin you'll just have to do some measuring, to see if it'll fit. :yes

 

[UntrustedAlly]

I will measure, thank you for all of your help! My last question is whether you think this project will be worth it. The Firebird I'm buying is $2000, runs and drives. Engine is free as it's coming out of my Catalina. Could I pull a decent profit if I restored everything, repainted, etc?

 

[ponyakr]

If you are doing this to make a profit, you are wasting your time and energy. There are a LOT of easier ways to make a dollar.

One thing against you is the 350. Not many guys want a low compression Pontiac 350. They want a 400 or bigger. :yes

The only good parts on that engine, to most guys, are the 6x-4 heads, and whatever else can be used on a 400 or bigger, engine. The stock Q-jet is an 800cfm, with the APT adjustment feature. And, the intake will also work on the bigger engines.

 

[UntrustedAlly]

I should have clarified - I'm not doing this for the profit, I'm doing this for experience and to possibly obtain a daily driver
I was just wondering about the profit if I ever was to sell it. I'd imagine it will only increase in value.