Inliners International Forums General Discussion Engines what size is my 6?

I looked up the casting number on the other page but it just said it's a chevy/olds 230-250. So which is it? How can I narrow down what motor is in my 65 chevy c10? the number is 3921968. ~j

Leo Santucci's book says it's a 230 cid vintage 1966-'70
Al

Pull a spark plug and look at the top of the piston. If it's dished it's a 250. If it is flat it's a 230.

I go with Al, the books says 230, wanna be sure, pull the head, get one cylinder to very bottom, if its 3.25" its 230, another 1/4" its 250. just my opine!

Yes I know if it has???? been rebuilt it could have a flat top. BUT if it hasn't been It will have either a flat top(being a 230) Dished if it's a true Non rebuilt 250 it will have a dished piston.As to what it came out of That didn't or doesn't really matter. IF it hasn't been touched in anyway and IS truly STOCK.
( I have yet to ever see a STOCK flat top 250 Even from any truck)
But yes it would be better to pull the head.Or maybe even the oil pan to be able to check the stroke.