I just removed a 1968 Pontiac 4oo from my 54 3100 truck and I need some help with replacing the motor mounts in the truck . The motor was put in back in the sixty's from the way it was engineered and the wielded mounts on the frame needs a make over . Does anyone have a Pontiac motor in there truck that could advise me on what to use . Thanks for any info
Contact Chassis Engineering in West Branch, Iowa. They make mount kits for many applications and also universal mounts. Also look at the way the factory mounted the Pontiac engine in the 55-59 GMC pickup. The frame is wider than an AD frame but one could pick up clues on how to go about getting the job done. On orphan installs we set the engine in the position we want and then with blocks of wood and tie wires make it stable so measurements will be accurate. Next we use 1/4" diameter solder to make a profile for the frame mount stand to the mount cushion (you can use soft wire). This is then transferred to heavy cardboard and a mock stand is cut to fit and taped together. After sliding the mock mount into place to check for fit the cardboard is duplicated in steel. 1/8 inch plate or strap is sufficient for most but if a long reach is needed then 3/16 is better. Only Chrysler needs 1/4". It's far easier to find a mount kit than build one.
The factory Pontiac in 55-59 GMCs used a single forward motor mount and side mounts that attached to the bell housing. Later Pontiac engines like this 400 used conventional side engine mounts and depended on the transmission for a rear mount, so not much to be learned from the 55-59 GMCs.