The Stovebolt Site Forums The Shop Area Engine Shop 1968-84 6 cylinder 250 rebuild

I have a 1968-84 6 cylinder 250 ID 328575 that I would like to rebuild. I am looking for info on doing the rebuild and info so I can order the correct parts for the rebuild. Is there any way to know if it was a 68 Chev or a 84 Olds?

i personally would take the block and crank to machine shop to get it checked. let them tell you if you need to get .010 bearings if they need to grind crank. they can also check the bores to see if you need to go with oversized pistons/ rings. that's what i would do to get started. if you order some "kit" before you have all the info it parts of it may not work. i like to hunt around for nos parts on ebay and save a little cash. the gasket set is the same for the 230/250/292. 2 kinds of timing gear sets as long as they are a set they will work. you wil have to make some decisions on if you want to replace everything or reuse some stuff. when you are asking about info are you needing torque specs specific to the 250 or info on a first time rebuild?

Check for date codes on the head and block, they will be something like (B239) where the month is the first letter( A=January, B=February. etc..),the day of month are next two digits, and the last is the year '79 or '69. The year is a tough call, it could be two decades apart or even three.
The newer heads will have the intake cast right on the head, older engines have the intake as a separate piece. All the heads are about the same just as the blocks are.

Check the area right above the top water pump bolt by the first head bolt( drivers side). This is the weak spot of the block. If the head bolt is over torqued, it pulls the block out of shape and cracks it where the water pump bolts on. They still run OK only they leak coolant from the crack. Its not repairable so look close.

If you rebuild it, install a flat top 307 Chevrolet V8 piston, its a bolt in swap but will raise the compression up to around 9.1 to 1. You will still be able to run regular gasoline but the performance will be improved with out spending extra money.

Joe