I just bought an '86 IROC. It is originally an LG4 car. I'm assuming the car now has an '87 or later engine because it has center bolt heads. The guy I bought it from doesn't know what it is because it was already there when he bought it. The engine has a computer controlled carb on it and looks to have been in there a while. I know it is a 350 because it says 5.7 on the rear driver's side of the block. Under that is has the letters "SGI" The front pad behing the alternator has the code "70831 TPA" on it but there is no VIN number on it. I'm guessing this must be some kind of crate engine since it doesn't have a VIN on it but I haven't been able to figure out what it is. The engine is still in the car so I can't see the casting number on the back of the block. I was hoping somebody may be able to figure it out with the "70831 TPA" code.

 

The 708... number isn't the casting number. Nothing on Mortec.com checks out under that number.
Sombody here will be able to tell you where to look for the casting number, but basically what you're looking for is an 8 digit number cast into the block somewhere obvious.

 

Yeah, I know that isn't the casting number. I'm not able to get that because the engine is still in the car. The "70831" may actually be "V0831" which would be a Flint engine made on August, 31st. However, the "TPA" is what I'm hoping somebody can decode. I have found quite a few listings of these engine codes but none lists "TPA".

 

if you go to mortec's site and E-mail them the numbers from the front pad behind the alt. they can send you the info. that number usually tells what kind of vehicle the motor was in originally. along with the year. just because it has center bolt heads doesn't mean that the engine is newer, those heads will fit on any small block.

 

I checked all my sources and come up with a 'TPA'

Double-check it to make sure.