Olds mounts on Pontiac block?

[G-Body_Vet]

I was at the machine shop the other bullshitting with the guy building my engine and we were comparing Olds vs Pontiac vs Buick.

For some reason we started talking about the differences in motor mounts and he said the Olds mounts should fit the Pontiac because they were made on the same tooling in the 70's. We went over and looked at an Olds 455 sitting next to my engine and sure enough, the bolt holes are in the same location.

Unless I've been living under a rock, has anyone else ever heard of or tried this? If Olds mounts work on a Pontiac block that alleviates a big pain trying to hunt down 301 or TA engine brackets. Now I'm curious if it would fit in our frames with the proper clearance.

 

[marcar1993]

Thought for you. Mount may be the same, but what about location in reference to bell housing and width of block at mount locations? If they are off by the slightest, it will not work.

 

[G-Body_Vet]

Thought for you. Mount may be the same, but what about location in reference to bell housing and width of block at mount locations? If they are off by the slightest, it will not work.

Even if it wasn't a drop in deal, if the mounts do indeed fit, if there's ample oil pan clearance and enough "play" to slide the mounts around on the crossmember (to drill new holes if need be) I guess it could be possible. I wouldn't expect them to drop onto the Old's frame location though. Just one of those odd things I thought I'd ask about.

 

[jcbannis]

the frame should be pre drilled my 78 gp was but i can not recall if i had 2 move the mounts or not when i put the 403 in it but thats been 15 years ago

 

[CGimbel]

Olds mounts will no work on a Pontiac.

To back this statement up....
When Pontiac put 403's in F-bodys they didn't use Pontiac engine mounts. The 403 Olds engine had an adapter plate to move an engine cup mount a couple inches to work with the Pontiac clam-shell frame mount.

Is it really that hard finding 301/265 engine brackets?

 

[marcar1993]

Olds mounts will no work on a Pontiac.

To back this statement up....
When Pontiac put 403's in F-bodys they didn't use Pontiac engine mounts. The 403 Olds engine had an adapter plate to move an engine cup mount a couple inches to work with the Pontiac clam-shell frame mount.

Is it really that hard finding 301/265 engine brackets?

Actually, they used CHEVY clamshell mounts, in the Chevy position with olds adapter mounts to work with them. Pontiac doesn't have clamshell mounts. They used the holes in the frame a camaro would use for its motor, and camaro frame mounts I beleive too. 😉

 

[Black Sheep]

Olds mounts will no work on a Pontiac.

To back this statement up....
When Pontiac put 403's in F-bodys they didn't use Pontiac engine mounts. The 403 Olds engine had an adapter plate to move an engine cup mount a couple inches to work with the Pontiac clam-shell frame mount.

Is it really that hard finding 301/265 engine brackets?

Actually, they used CHEVY clamshell mounts, in the Chevy position with olds adapter mounts to work with them. Pontiac doesn't have clamshell mounts. They used the holes in the frame a camaro would use for its motor, and camaro frame mounts I beleive too. 😉

Sorry marcar, but that is not even close to being correct. In the 77-79 F-body, the pontiac and olds engines used the same frame mounted mount, in the same spot, but used different engine bracket mounts. And while the frame mounted mounts look like chevy mounts, they are slightly different and have mounting holes in different locations. Plus, the mounts for a chevy are in a completely different location.