307 to 350 frame mount, height difference?

[Stu Seitz]

Searched but couldn’t find anything on this topic. Does anyone happen to know the height difference of a 307 frame mount as opposed to a 350 frame mount? This is of course, going on a 1969 Camaro

[MrQuick]

I thought they where the same height?Just the 350's where slotted on the pass side. Only diff were in the SBC (exc 302 & LT1)) and BBC ones.

[PRO TC]

i would think thay would be the same. i have my 69 subframe out of my car right now and it had a 350. if you want me to check let me know

barry

[Stu Seitz]

I thought they where the same height?Just the 350's where slotted on the pass side. Only diff were in the SBC (exc 302 & LT1)) and BBC ones.

307 and 327 are the same, as are the 302 and 350 frame mounts.


i would think thay would be the same. i have my 69 subframe out of my car right now and it had a 350. if you want me to check let me know

If you could that would be great, I need the measurement from the very bottom (the face that actually comes in contact with the sub frame) to the center of the hole, which I believe is actually more of an oval shape.

[vintageracer]

There is a different frame bracket for a 68-71 Chevelle with a 307 (GM #3980707 left & 3980708 right) and the 307 uses a smaller (different) standard duty engine mount.

The 350/396/454 engines use frame bracket (GM#3980711 left and 3980712 right) with heavy duty engine mount GM#3990318.

The correct frame brackets are not available at GM however any of the restoration houses will have the correct frame mount brackets. You can "force" a heavy duty engine mounts used on 350/396/454 engines onto a standard duty 307 frame bracket however it is tough. The engine will drop in with the correct frame bracket and correct engine mount. The problem with fitment when trying to use a 307 engine frame mount and 350/396/454 engine mount is on the passenger side. The 307 engine frame bracket is significantly smaller than the 350/396/454 bracket. Very obvious when sitting side by side. I cannot remember if or how much difference there is in height.

I'll bet Camaro uses the same engine frame brackets for a 307 engine car as a Chevelle since GM was very much into using parts already available. Therefore when coverting a Camaro from a 307 to a 350/396/454 "I" think you MUST change the engine frame brackets just like in a Chevelle. Check your frame brackets as this is probably where you have problems. You need the correct engine frame brackets to solve your problem!

[Stu Seitz]

Thanks for the input but I can't really "force" them in because I'm using solid mounts.