Shinerunner

Hello everyone. I am a new member. Great to be here. Fyi I am not a mechanic . This is my first project.
I have a53 olds 88 holiday coupe all original. All parts are there. It's locked up can't free it . Using all the fluid concoctions in cyl. I took the heads off cyl were not too bad some scoring.
I am torn about what to do. I think engine needs bored. Rebuilt. I am also considering an ls swap. But no experience. Have a friend mechanic can help me. I like keeping original. But like idea of modern ls power . Would appreciate any suggestions. Thx todd

Charlie Jones

Installing an LS engine in this car is a major project, certainly not a "first project " for someone who "is not a mechanic".
Overhauling an original 303 engine is much simpler. Even though the engine is "locked up".
Especially if you find a machine shop that has experience with these engines.
If the engine is locked up it WILL need to be rebuilt.
The best way for you to proceed is to remove the engine and trans together. Since you have the heads off already, this will make it easier.
The engine can't be separated from the trans until you can turn the flywheel and crank. You must remove all 30 bolts on the torus cover.
Remove the oil pan and remove all the rods and pistons you can. Pistons can be driven out from the bottom with a drift. You aren't going to re-use them anyway .
Once the engine is apart. take it to a machine shop and they can tell you what size the cylinders need to be bored to.
303 cylinders are thick, so they can be bored up to .125 oversize. At .125 over 324 standard pistons can be used.
You may not need to bore it out that far, but you can.
Here is a build thread on a 394, but the principle is the same.
394 "Rocket" engine build - ClassicOldsmobile.com
A good source of engine parts is Egge Machine;
Egge Machine Company

Tedd Thompson

What Charlie said above. For me, it's as easy to remove the engine and transmission together, you have to anyway no matter what way you go, but don't let that scare you away from pulling it. It's probable that your mechanic doesn't know that he can't split the engine from the transmission while still in the car if it won't turn over, unless he is an old timer with Oldsmobile anyway.

An LS swap may sound like fun with the added HP but with it would come many expensive extras like improved brakes, motor mounts, different transmission, cross member add, and probably drive line lengthen or shorten and a bunch of small items too many to list. It's a lot more involved than dropping an LS into a more modern GM car. Many changes in the last 70 years in frame body, rear end, steering. But the biggest loss in my mind would be the nostalgia of loosing that 303....Tedd

Sugar Bear

Because it's a coupe, it's original and it's survived 70 years without being modified I would absolutely preserve it as much as possible. The only engine I'd put in it is one that is period correct. I would be ok with boring the 303 to 324 with some modern tuning, throttle body injection etc. with dual exhaust.

Good luck and please post pics.

redoldsman

If you have never done an engine swap, I would say it is close to impossible to do an LS swap into this car. If you did an LS swap you will need a completely new suspension under the front of this car. The car has a very antiquated suspension. It doesn't even have ball joints. It uses kingpins and bushings. And we haven't even gotten to the brakes. Even rebuilding the 303 will be lots of work. Good luck on your car.