I have a 66 Chevy stepside and I'm wondering what is the engine. I don't think it's original.

Here's the relevant numbers found on the engine block (all are on passenger side)

B157 (I'm guessing this means Feb 15, and that last number could be 1967, 1977, 1987???)
877127 (I'm guessing this is the casting number,
and there's some possibility the first number is a 3 instead of an 8, so maybe it's 377127)

Stamped is the number F0217 CCF
I'm guessing this is Flint, Feb 17

CCF when run through the nastyz28 web page yields three engines:

1970 230 L6 140 GHP
1976 250 L6 105 NHP
1977 250 L6 110 NHP


So should I conclude that because of the "7" in the other number, that this is a 1977 250 engine?
Does the casting number help?

Just want to be sure I'm on the right track. Any other info you guys can provide would be much appreciated.

thanks,
Jeff
amato@nmsu.edu

Your second guess at the block casting number 377127 showes up in my listing as a 75-76 250 l6 with integral head. The question maybe does it still have the integral head. They may have kept the stock head with separated intake and exhaust manifolds.

Larry
68 C20 327 daily driver
63 C20 292 Camper truck
65 C10 ? Custom Cab AC,PB,PS,$flasher

We have a Casting #'s section on this site, look at the lefthand column.
Our list says 377127 is a 73-79 250. I would say it is probably a '77 250.
Take a look at the top of the pistons, assuming they haven't been changed, then a 250 should have dished pistons, a 230 would have flat tops.