Grog Posted July 20, 2002 Share Posted July 20, 2002 BTW, the motor mounts on a Pontiac are not interchangeble with chevy, as well as the intake, ross, heads, etc.... Thats why a Pontiac is a Pontiac, and a Chevy is a Chevy. Quote Link to comment Share on other sites More sharing options...
Guest 400 ci 280z Posted July 20, 2002 Share Posted July 20, 2002 that is fine and sorry if i sounded really impatient. i will be looking forward to your pics of the mounts. thanks Quote Link to comment Share on other sites More sharing options...
Guest Tom Scala Posted July 20, 2002 Share Posted July 20, 2002 No flame here,one sure fire way to ruin an old Pontiac is to put a Chebby in it. The worst offenders were the ones who put a 350 SBC in an original 400 and up Firebird or GTO. "Hey,lets put this little,less powerful motor in that thar Goat & slap a Bowtie on the grill,bitchn' man". Very common in the 70's,but then again so were leasure suits. As far as the frame brackets the holes were in the same place but the brackets were different between Chev & Pontiac, and the motor mounts themselves arent even close. The pre 70's Pontiac blocks had 2 motor mount holes per side, and the latter ones used a different mount and had additional holes but also had the 2 holes in the older location so they could be swapped into the 60's cars easily. If your using cast iron heads don't go abouve 9.5 CR with pump gas or detonation may become an issue,the big Pontiacs are more succeptable than the SBC. Cool swap,good luck with it. Quote Link to comment Share on other sites More sharing options...
Grog Posted July 22, 2002 Share Posted July 22, 2002 Tom is absolutely correct about the motor mounts. The rubber mount isolators and crossmember location in a Pontiac and Chevy are one thing, but the motor mounts themselves are two different animals. When I fabricated my motor mounts for my Pontiac swap, I did it in such a way to utilize the rubber mount isolators per the JTR book. I was unhappy with this for several reason, but to name a few they were 1) raised the installed engine height by three inches) the foward of the engine was at a 10 +/- 1 degree incline relative to the ground. This precluded the use of a flexfan and affect the functioning of my carb when launching (it would stall) because the float bowls wouldn't fill properly, and 3) couldn't close the hood when using a full size air cleaner with a T/A shaker scoop installed on top. Needless to say I re-invented the wheel once again and refabbed the mounts where all three of the previously identified problems were solved. If I could figure out how to include images in these posts I would post a few pics but my garage skills are much better than my internet skills are. Quote Link to comment Share on other sites More sharing options...
Guest 400 ci 280z Posted July 23, 2002 Share Posted July 23, 2002 grog, can you use aftermarket headers after you fix the steering shaft? or is there just not enough room? also how well does the car hook up for you? thanks Quote Link to comment Share on other sites More sharing options...
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