I'm about to purchase a used 350 from someone. How can I be sure that it is a 350 and not a 305. The engine will be assembled with intake and exhaust manifolds so I won't be able to see the engine bore. It has a "57LG" on the back left of the block. I thought that signified a 5.7 liter, but after reading some old posts it seems that some people have had 305's with that stamp. The engine is out of a 88 IROC TPI.
thanks,
Chris

 

If it says 5.7LG it's a 350. If it came from an 88 it should also be stamped on the front side of the engine 5.7 or 350. Whats the casting number?

 

The casting number on the right rear side is 4093638.

 

Are you sure there's not a 1 in front of that number??

if so, then:

14093638...350...87-95...2 or 4...Roller or flat tappet cam

which would make sense for an '88 Iroc with a 5.7L.

 

do 305 and 350's have the same stroke? if they didnt couldnt u drop a long stick into the cylidner and measure the stroke?

 

same stroke diff. bore 3.75bore-4"bore....

 

doh