The Stovebolt Site Forums The Shop Area Engine Shop 1968 chevy 250 to replace a 235.

I am in the process of swapping a 250 6 into 58 biscayne that has a very tired 235, I have read that the flywheel and bell housing will need to be replaced with one from a 283/ 327. But i have not been able to confirm this reliably. you folks were such a big help when i was building the 58 apache that you were my first thought to get the information with any degree of reliability.
any other words of wisdom on this subject would be appreciated also.
thanks Mike Bourg

You are correct. The 235 bolt pattern will not work with a 250. You will need to get a later model bell housing designed for a 230/250 or one designed for a small block V8 (265/283/327).

thanks for confirming that, now next will the 235 flywheel bolt up or do i need to find another one that will work on the small block???
Mike bourg

Nope- - - -you will either need a standard shift 230/250/292 flywheel or possibly the V8 flywheel will also work (not sure about that, though).
Jerry

The V-8 small block Flywheel will work as well up through 1985, and so long as it is not for a small block 400 or any of the big block V-8s.

Correct about the SB 400. They are externally balanced and it is done on the flywheel.

The 400 harmonic balancer is also unique to that engine. 400's get an off-balanced item on both ends of the crankshaft. The crankshaft has a dowel so the flywheel will only fit in one position.
Jerry

Be a little careful with 292 flywheels, some used 1/2" bolts instead of 7/16".

well the stovebolt has come through again all the information I needed was here. I wish to thank everyone for their help.
Mike Bourg

Well it looks like I will be needing some more assistance from the folks on the stove bolt, I have rounded up all the back end goods, flywheel, bell housing , clutch starter etc now I have hit another stumbling block, the motor mounts to get this installed in the 58 x framed biscayne, I have found all types of mounts for the earlier cars, but nothing for this one, the bad part is all i need is the stock mounts that fit on the engine not the rest of them. part number would help, but so far no luck. Napa even struck out.
this is turning into more of a project that I had planned on, but fun.

thanks Mike Bourg

58 up cars used center mounts on the engine with a mount on the rear of the trans on both the 235 and V-8 applications.
Passenger cars used the X frame through 64.
Since the newer style 230/250 engine was used in 63 up cars it seems likely to me that the mounts from a 63 6 cyl or V-8 should work on the 58 as well.
Fred

I know the v8 mounts wont work, and I know that the mounts for the 235 will not work, at least the portion that bolts to the block, the bolt pattern is slightly different and the drivers side on the 250 has an offset of about 3/4" from top to bottom. I may have to fabricate some thing that will work, but I am getting lazy in my old age.

Mike

well just an update, we ended up modifying the 235 mounts and it worked out ok, also we ended up haveing to move the 250 back 1 1/4 inches so that the trans mount would work, took yhe frame mounts and swapped sides and welded them in place, then everything lined up and we are good the finish it up.
Mike Bourg

Excellent!! Glad to hear the good news.

Ok, we finally got everything in order and all the duck were in a row, fired it it and it ran like a champ, set the valves after it warmed up and all is good, now to get all of the small things taken care of and the car will be on the road this weekend. it sure sounds far better than the tired 235 we took out...............

thanks to all for the help, Mike