Does anybody know of a website or somewhere that i can lookup block VIN numbers for 350 TPI's. I keep hearing that when ppl buy 350's, then take em home then turn out to be 305s. I just want the block numbers so i know i'm good. Thanks guys for any help.

 

On the back of the block, the last 3 digits of the casting number will be '638' for an original 350 TPI if I remember correctly. The VIN code will be '8'. Don't bother looking for a VIN code on the engine and trying to decypher it.

 

Just an FYI - the block will be stamped "5.7L" as well. You will need to clean off some grime on most cars to see it.

 

Finding the "638" on the block, is that for all year IROC's? My IROC is an '88 i'm am looking at a '89 block.

 

It should be the same for all one piece rear main seal blocks. I don't know if it is different on older two piece rear main seal blocks. G.M. doe not change casting numbers every year on engine blocks. The casting number only changes when the casting is changed.

 

Now the block VIN is on the back of the block, in front of the bellhousing right? I forget where the hell their at, lol.

 

On the bellhousing flange, right behind the drivers side head. Its a long, 9 or 10 digit number, but you only need to get the last 3 digits (the number reads from the outside in towards the middle of the motor).

 

if it is an older block the casting # can be looked up on a web site call "mortec.com"
the newer block with the 1 pc rear mail seal will have the sive cast in the bellhousing flange behind the head in ltrs ie: 5.0L or 5.7L these are the easiest way to tell. untill you can menorize the casting numbers.