Found out something interesting..

[MTBADBOB]

Originally Posted by chevyrestoguy

Look on the back of the block at the part number. It should end in -509 or -817. The later 400s were almost always the -817 blocks. It's a 2-bolt main, but that's actually a good thing. Those engines got a bad rap years ago for no reason at all, usually from people that never owned one. A 400 is a great engine for a street machine. It's give you the torque of a small big-block with the size of a small block. I'm a huge fan of 400s.

I say build it! You'll like it, trust me.

Amen, I totally agree about the sb 400's. I had a '76 Monte that had a stock 400 and that was one of the best Chev motors I've ever owned! It would outrun every stock motored car I came across, other GM's, Ford 400 BB's, 351's, Mopar smallblocks, etc..., and still pull 21-23 mpg! All I did was run a/c lid turned over, air screws out about 5 turns, & advanced about 8 degrees. It was very impressive for a stock engine in a BIG car! I blew a belt one night out partying & the "alcohol" told me to try & make it home at 100+ mph!(what an idiot!) ended up cooking it. I replaced the cracked heads, but it also cooked the rings, never the same after that. One reason I no longer consume alcoholic beverages!