GTO Engine Swap

Hello All,

I need help with swapping out a Blown (Non Fixable) 73 455 IN A 69 GTO with a 76 400 that came out of a 81 Trans Am. The 400 did not come with motor mounts and the 455 motor mounts that I have will NOT work on the 400. The frame mounts on the GTO are factory. I have never delt with this kind of thing before. What do I need to do? Please help?

Surely this sort of thing has been done before. Any help in this matter is GREATLY appreciated.

Thanks In Advance

Darrell

I was considering virtually the same swap...........removing my worn-out original 400 from my '69 GTO and installing a '77 400 from a Trans Am.

If I recall, the GTO mounts have 2 bolts to the engine, and those later 400's accept 3 bolts...right?

My gut feeling is to break out the welder and the drill and do a bit of fabricating on the old GTO mounts....but if someone has a better idea, I would love to hear it.

I was considering virtually the same swap...........removing my worn-out original 400 from my '69 GTO and installing a '77 400 from a Trans Am.

If I recall, the GTO mounts have 2 bolts to the engine, and those later 400's accept 3 bolts...right?

My gut feeling is to break out the welder and the drill and do a bit of fabricating on the old GTO mounts....but if someone has a better idea, I would love to hear it.

Thanks for your super quick response. I was really hoping to NOT have to gerri rig it. I have a few ideas which include the welder and the drill. But, I was really hoping to not have to resort to that.

I spoke with someone the other day about this, this is what he told me,"just get the mounts for the 400 and then all you have to do is move the frame mounts forward to the next set of holes". Mind you, I have no idea what the mounts look like for a 76 pontiac 400. They must be quite different than the ones for my 455. What do you think of that? Is it doable? or was he just another person blowing smoke?

Darrell

I do seem to recall someone said to me the later engine mounts will work in the earlier frame. However, I also thought the 400 and 455 mounts were the same.

Through '69, all GTO and Firbird blocks utilize the "2-bolt" mounting flange. '70 through mid '76, all blocks had 5 mounting holes, making them interchangeable across "all" years. Mid-'76 and newer have but three holes in the block. This applies to the 400. Virtually ALL 455s were "5-bolt". The mounts use either 3 or 2 bolts. None use all 5.
The "best" blocks (subjective criteria) are the '70-'mid '76 blocks with 5 mounting holes. Not because they fit all the eras, but because there's more "meat" in the bottom of the bore, making them better candidates for performance builds.
Ames Performance, Performance Years, Indian Adventures, plus a few others, sell an adapter kit to cross eras with blocks. Call them and tell them which block you want to put in which car, and they can send you ther appropriate stuff.
Jim Hand's book "How to Build Max-performance Pontiac V8s" has most of this info in it. Good reading. Necessary reading if you haven't built a Pontiac lately...

Through '69, all GTO and Firbird blocks utilize the "2-bolt" mounting flange. '70 through mid '76, all blocks had 5 mounting holes, making them interchangeable across "all" years. Mid-'76 and newer have but three holes in the block. This applies to the 400. Virtually ALL 455s were "5-bolt". The mounts use either 3 or 2 bolts. None use all 5.
The "best" blocks (subjective criteria) are the '70-'mid '76 blocks with 5 mounting holes. Not because they fit all the eras, but because there's more "meat" in the bottom of the bore, making them better candidates for performance builds.
Ames Performance, Performance Years, Indian Adventures, plus a few others, sell an adapter kit to cross eras with blocks. Call them and tell them which block you want to put in which car, and they can send you ther appropriate stuff.
Jim Hand's book "How to Build Max-performance Pontiac V8s" has most of this info in it. Good reading. Necessary reading if you haven't built a Pontiac lately...


Thanks MrPBody,

I have located some mounts for this 76 400. They are the 3 bolt kind. Now I just need to find out if they match up to my frame mounts and if the frame mounts need to be moved to the other holes. Hopefully the frame mounts don't have to be changed too.


That will probably be a next weekend project.

Thanks again

Darrell

I do seem to recall someone said to me the later engine mounts will work in the earlier frame. However, I also thought the 400 and 455 mounts were the same.

Thanks for the help. The mounts are very much different from 73 to 76.

Thanks again

Darrell

Hey I'm new to this....can anyone tell me where to go to find a 67 WS 06C block or engine? What chat room should I be searching in?

Thanks

Allen,

A WS? TALL order...
Try the following sites:

performanceyears.com
classicalpontiac.com
boyleworks.com (muscle cars)

All three sites have good classified sections, and are Pontiac-specific. That block is pretty tough to find. There may be one out there, so don't depsair!

You might also consider getting Jim Hand's book "How to Build Max-performance Pontiac V8s" by SA Designs. Current and accurate.

Jim

You can get the change over mounts at www.amesperf.com

LOL don't drill anything, it's just to easy to buy the parts so you can allways go back.

Hope this helps