The Stovebolt Site Forums The Shop Area Engine Shop how to tell what size motor

I have a 1965 chevy truck. It has a straight 6 in it . I would like to know how to tell if it is a 230 or 250. I have been told it was both by differnt people .please help

here are block casting numbers fro the two engines, 230 from 1963-'65, #3788406, 1966-'70 230, #3850817, 3854036, 3877178, 3921968

250 from 1962-'79, 328575, 348675, 366855, 377172, 2775308,3850817,3854036,3877178,3921968

As you may notice they used the same block thru some of the years. The crank and pistons are different. You may have to take it apart to no for sure! They even used the same same head on some of them.

Joe H

You can also tell what engine it is by the type designation in the serial number (the one or two letter suffix).

Look for the stamped number on the pad by the distributor. Last 2-3 are the engine code.
http://no25.homestead.com/page3.html