Quote:
Originally Posted by cdrookie
74 and 75 both use the clamshell motor mount. It can be a PITA to get all the hardware off the frame mounts though, not easy to get a wrench into a couple spots.
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If you want to make it easier to get the nuts inside the crossmember I use a step drill to make access holes in the bottom of the crosssmember that you can pass a universal socket through with an extension to hold the nuts. You need roughly a 1 inch hole to pass the hardware through. You can make one in the center of the crossmember that you'll be able to reach both sides with a long extension and a swivel. It's easier, and quicker than trying to work around the lower control arm mounts, or pull the lower control arms out to get more room.
I first did this when I converted a 82 Cutlass 4.3 V6 diesel to a 350 Rocket gas engine, there is very little room in the G body to get any wrench into the bottom of that crossmember. The 1 inch hole worked very well for access, much easier than removing the lower control arms.
I rechecked Anchor's listing on Advance auto parts site, and Amazon, both sites say the V8 Pontiac V8 through 1976 uses the 2255, and 2256 mounts which are not clamshell mounts. They confirm that 1977 is the first year that the clamshell mount was used in a A body with a Pontiac V8. Not going to get into a disagreement here, but as far as the parts sites listed usage, a 350, and 400 Pontiac V8 both use the early style mounts. It's well known that the A body cars beginning in 1970 used the late style 3 bolt mounts, and the 350, and 400 cars used the old 2 bolt mounts. Since Pontiac used the stronger mounts in 70-72 455 A bodied cars, it's entirely possible that 73-76, 455 A bodies also used their own seperate mounts. Amazon does show the clamshell style mount on the earlier chassis, (73-76), but only on OEM 455 equipped cars.
I guess Scott can confirm what mounts his donor cars have when he gets around to removing the frame mounts.
I may have learned another Pontiac engineering design variation for the 73-76 A bodies. I was never aware that there were 2 different designs for 350/400 cars, and a seperate design for the 455 equipped cars during those years.