Help with engine number decode.

Well, got an engine sitting here and so far, i think it's a 400 maybe a 71??? My book only lists the casting numbers so i'm not sure? Here are the numbers.

3951511 left rear flange by bellhousing

TO828CLK

11c103963 these 2 are on the pad stamped at right front behind alternator

Bump!

pulled off a chevelle website..
There are only 3 400 block castings; 511, 509, 817. The 511 is the early one (70-72), the 509 & 817 are the later ones.

The later ones are possibly "better", which is NOT the same as saying that the 511 is "not good". Maybe, just not quite as good, for SOME things. But for a street or moderate racing application, it's not a significant difference, and I wouldn't let that bother me if I was you. For a budget hot street motor it'll be perfectly fine.

It'll almost certainly have factory 4-bolt main caps installed on it.

Cool, thanks for the info 007. It is a 4 bolt and I bought an aftermarket steel crank for it. I just wanted to make sure because the 400 is externally balanced. 350 (which i thought it was), is internal so I wanted to get the right balancer flyweel etc. Thanks again!

not a problem man.. if i would have seen the post sooner i would have gotten to it sooner

No problem. This is a long term project so I am in no hurry.