I have a 1955 Pontiac Chieftan with a stock 287 engine and a three on the tree. The engine is pretty tired and smokes through the breathers like crazy. I have located a re-built 1965 389 and would like to put that in instead of re-building the 287 and putting a Saginaw 4 speed behind it. Any ideas on what problems I may encounter in the swap? Will the flywheel from the 287 work with the 389? Motor mounts the same from a 287 to a 389? Any help is appreciated! Spike
There really won't be any usable parts from the 287 for the 389. Flywheel and engine mounts are all going to need to be for the 389 and side mounts will need to be built onto the frame. The steering gearbox will be in the way also. An easier option would be to find another engine from 55-60 and would be a bolt in for the existing trans and driveline.
55 pretty much covered it. It's not like it's rocket science but it's a good bit more than just a pull and swap. I have a great running 389 also but my 316 runs good so the effort isn't worth it (right now).
X2. I vote for a 1960 389 specifically. Check Craigslist and or Smoke Signals magazine (POCI club publication). Cool car and cool idea.
Also the exhaust manifold on the driver's side comes really close to that steering box, so make sure you save the manifolds off your old engine if you do a swap. I don't think those manifolds fit anything newer than 1960 either.
I initially had built side mounts for my 66 389 in my 55. I used early a-body exhaust manifolds( 2 bolt flange) and had a rear exit on the drivers side, but the engine was quite a bit higher and off to the p***enger side. The master cylinder is real close to this area also for manual brakes and i'm also moving that up to the firewall. But if you can do alot of the fabrication yourself to keep the cost down than go for it. I built this simple adapter on the drivers side to move the mounting point forward to clear the gearbox and made side mounts from some 2x2 tubing 1/4" thick and cut at a 45 than welded 1/4" plate to use the factory frame mounts. The 287 uses a 3 point mounting system also but uses the timing cover than 2 rear side mounts for the trans. I've since changed and went to a Hurst front mount for a more period correct look. The side adapter is 3/8" plate and doubled up and threaded there for the factory mount to bolt up. Also on the exhaust manifolds, the 55-56 manifolds have smaller openings than later manifolds, so using them on any newer engine than 56 would be restrictive. 57-58 manifolds would work better if keeping the front exit setup on the drivers side.
Just wanted to say "thanks" for all the responses. I have decided to re-build the original 287 and add a 4 speed to it as well. At least then I'll know what's in the engine! Thanks again' Spike
hey spike im just curious to what exactly your gonna do to your 287. did you buy a reuild kit, are you doing it yourself? i have a 55 poncho too and im just wanted to know, so when i need to pull mine and rebuild it wheres the best place to get what im gonna need thanks
You are aware that your '55 standard shift bell housing is a weirdo, and that a later four speed won't even come close to bolting to it, right? You would need a '58-'60 bell housing in order to use any four speed with the standard G.M. pattern.
Why wouldn't the '55 flywheel work on a '56-'60 engine? Schiefer listed the same part number to fit '55-'60 Pontiac engines.
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