I'm looking to do a swap of a 71 Pontiac 400 motor into a 55 Pontiac. Has anyone done this type of swap? What motor mounts to use etc. Are there ant swap kits available. Any help would be greatly appreciated. Thanks
I just put a 455 Pontiac in my 48 Olds, but I had to make my own mounts which extended back from the front cross member, and bolted to the side mounting surface on the block, and they are hard mounts. I don't see why you couldn't make a tube cross member which ran under the front of the oil pan, and used the stock motor mounts. My motor mounts came out of a 68 Bonneville, so the rubber part bolts to the engine. I know the later mounts, the rubber part bolted to the cross member, which would make it harder to mount to a narrow cross member. If nothing else, BTTT
Indian Adventures used to sell a mount kit for that, but it's not on thier website anymore. Checkout their website or give them a call they might be able to help you out. http://chiefmanyhorses.com/ I've attached a couple of pics that might work, I also have an old Rodder's Digest tech article where Gerry Burger swaps in a later model 421 in his "Project Stratostreak". If you would like a copy of the article, send me an e-mail and I will get it scanned and e-mail you a copy. I plan on putting a 68 400 in my 55 when I get finished with my T roadster project.
Go to: http://autos.groups.yahoo.com/group/pontiac-1950s/ It's a big site but I know they've covered this many times before.Rick Gonser heads it up and it has a wealth of Pontiac info.
You need to look for Rocky.........He'll know LOADS. I swapped a 60 389 into my 55 Pontiac EASY. Slid right in, but it uses the center motormount like my 55 287. Later motors are side mount and your car isn't set up for that. Sounds like more work then I'd want to do..........nothing wrong with a 389! xxx Brandy
I'm doing this over the next few weekends. 73 block, 55 860. I'll be posting pics. Destructo, I'd love to get a scan of that article; [email protected]
Two ways come to mind to do this. Cobble in the motor mount stands to mount the stock late model engine mounts and hang a rear crossmember to use the rear mount of the transmission from the same late model. OR (my preference) The bottom of all Pontiac V8 front covers are shaped like the original 55 through 58, and although the newer ones are aluminum, you can bolt the original front mount to them by carefully using the bracket to drill the bolt holes. DO NOT USE THIS MOUNT AND USE A REAR TRANS MOUNT! Even with torque rods to control the side to side movement, The strain on the bellhousing would be asking for trouble. To make this mount work would require the use of side mounts at the bellhousing. Once again a couple of ways come to mind. Make brackets out of aluminum plate and tig to the bellhousing to mimic the original bosses for mounts, or (and I prefer this one) make a motor plate out of steel to sandwich between the block and bellhousing. I remember starting to mock this up, but it's been over 25 years and I don't recall if there was a clearance issue with the stock isolators and their molded in brackets. Even so, it would be relatively simple to come up with a couple of ears to mount early Ford style biscuits. The late model starter is a non issue because it mounts to the block. As all Pontiac V8 motors share the same architecture and size (Pontiac didn't even change the deck height), once the front mount was bolted to the block and the crossmember, and the carb mounting pad was leveled by blocking up the rear, the rest should be pretty straight forward to mock up. Doing it this way would leave lots more room for exhaust, steering, etc. and WOULD NOT alter the frame. I seem to remember cracking issues around the steering box with the stock channel frame and don't recomend altering it unless you're prepared to box it.
I'm was considering using the late bolt holes and a custom corssmember. I think I'll use a front motor plate. The trans mount will be easy.
I just saw a engine plate on ebay for a Pontiac, it fit under the timing cover. Here's a pic of mine, but it is hard mounted, so some probably wouldn't like that. I like the vibration
i snapped a couple pics tonight of the ones that my bro,and i finished last weekend.there for an olds.looking at that factory pic that was posted it looks like some of the mounting is simular.i think you could bolt them to the frame,but we welded.i just took the desighn from the speedway catolog for 55-57 chevys.these are a bit longer.soo we made gussets. eric
Thanks. Thats what I have been looking for. Im going to try to use stock motor mounts on mine and make entensions to mount it to the frame. I think I will have to weld mine the way my frame is. Its kinda boxed in that area and I dont think I can get a nut in there
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