1969 pontiac 400 into a 78 Grand Prix

buzz77 said:

These may work. Would they use the stock 301 motor mounts?

Click to expand...

I believe those would bolt to either block, '69 and older or the '70 and up. They appear to have bolt holes for either. If your car had a 301, the frame side should already be correct. I think you could bolt these mounts to your block and be good to go. I'm sure the guy selling them could confirm more than I car. I didn't know that they made these adapter mounts. Well, at least they used to...

I'll try to contact him on that site and get him to look here.

These brackets are for both 65-69 and 70-81 and will work, or get factory pre 1970 brackets with any year 301 clam shell mounts.

http://butlerperformance.com/i-2462...lerperformance.com/search.html?q=motor+mounts

The adapter plates Butler sells will allow the use of the later motor mount on an early block. However, all other body style block mounts don't work right. Once you set both mounts side by side, the difference is easily visible. I tried and ran the f body mounts for awhile, the motor sat too high and wasn't a "bolt in." By the motor being too high, this created other issues with header fitment and header to firewall clearance.

Buzz77- that "mechanic" should be keel hauled. He tossed the single most important part for your swap. Idiot. Anyway the Indian Adventures parts tdvick posted looked like winners to me. I also had no idea they were being sold. Probably worth a serious search. Sometimes Ebay has the stock GM units. Anything for F, B, or older A bodies won't work right. They will bolt up- but the motor will sit high and besides the other issues posted, the fan will hit the shroud. I've tried them all.

Buzz77- what heads are on that motor? Most stock '69 heads are high compression and may not like today's cat piss gas.

1969 #48's?!? According to the Wallace Racing chart [http://www.wallaceracing.com/head1.htm ] that motor was a high compression big horsepower manual transmission beast. [1969 400: 330,335,350/366HP 62/48(MT) 2.11/1.77 72cc] It may even be an HO/RA motor- does it have 4-bolt mains?-what is the block code #? Did you use dished pistons or custom low-deck ones to get the compression down? Pontiac used the same standard pistons for all the motors and adjusted the compression with large and small chambered heads. Look for the 2 letter block code that is stamped just below the passenger's side head. Check it against this chart- [http://www.wallaceracing.com/engine1.htm] You may have a rare motor there.