I just picked up a 87 trans am gta, i was told by the previous owner that it had the 305tpi in it but he was told by the guy he bought it from that is had been swapped to 350tpi. I looked up the vin code and verified that it originally came with the 305tpi. I cannot tell the difference between the two by looking at them.

Can anybody tell me how to distinguish between the two motors without finding the block number. I will post pictures ASAP.

The car definitly pulls hard, but ive never before driven a trans am so i wouldnt know the difference. Thanks, Josh

 

This is rather easy. Get a flashlight and peer down behind the driver's side cylinder head. a 305 will have 5.0LG cast there, the 350 will say 5.7LG.

 

I cant find it, i did a full tuneup today and couldnt find it. Is it near to firewall? Is it on the top or bottom. Thanks, Josh

 

Near the firewall. Almost under the firewall.

Another possibility is to look for a 3 digit number cast into the side of the block. You'll have to look for it from underneath. Get that, and we'll be able to tell you which it is.

 

Can anybody tell me exactly where these two numbers are, ive searched everywhere, ive scraped the dirt off, used mirrors. Its ridiculous, should be easier to identify than this. Thanks, Josh

 

57 is the man, just do what he says, and dont forget google.
http://www.google.com/search?hl=en&r...numbers+gm+350 is the link that talks about where gm puts the numbers on gm blocks. see i even did the google search for you.
if we tell you, you will just forget.
if you find it yourself you will be proud you could find it and you will never forget.
good luck
tony

 

www.mortec.com

 

What side ids the oil dipstick on?

 

its on the passenger side, the tranny dipstick is close behind it, ill post a picture in a few minutes.

 

heres the Pics,







heres a fun pic, i like this emblem

 

That only distinguishes between '57-79 and '80-99 blocks. Won't tell you what the displacement is.

 

Sorry guys but i cant see those numbers, ive worked on countless engines and have never had this difficulty, what freking moron put them under the firewall

 

Take off a valve cover and get the casting number from the cylinder head. Both heads will have the same number, so it doesn't matter which one you take off.

If we know what heads are on it, we can at the very least make a good educated guess about what the engine is.

 

On a 22-year-old car, I wouldn't bet on that.

8 years ago, I picked up an '87 LB9. It had 2 different casting heads on it, one the correct 081 TPI head, the other a swirl-port LO3 head.

But, getting the head casting #'s isn't a bad idea, regardless.

Have you gotten underneath the car and looked for those 3 digits? That's a lot easier than what you've gone through so far. Have a good light with you when you do this.

 

I havnt tried looking for the numbers under the car, do you know where they are, thanks, Josh