I am picking up a 350 TPI from a junk yard next weekend. How do I ID it to be sure its not a 305 TPI. And I need to pull the harness/PCM out of a car too how do I tell the difference between the 305 TPI and 350 TPI harness/PCM?

 

Rear of the drivers cyl head there will be a stamp of either 5.0L or 5.7L. Its very difficult to see with the engine installed, so pull a valve cover and check the head casting

Harnesses are identical for 5.0 and 5.7 TPIs, but beware of the year changes

Check the PROM code in the ECM for a 5.0 or 5.7 flash. Generally the ECM and engine are matched so if you identify one for sure, the other usually follows suit

Quick give aways, T-tops, vert or 5 spds are 5.0's. There were some exceptions with t-top 5.7's, but low build numbers and desirability would normally keep them out of JYs

Good luck

 

ok cool so my problem is gonna be the PCM. The engine is already pulled for me (charged me $25 for them to pull it, and that was worth it to me haha) They claim its a 5.7 and I just want to be sure before I drug it home and had a disappointment. But the harness and PCM are not with the engine so I need to go search the yard for PCM/Harness. What other vehicles did the 5.7 TPI come in? And would PCM usable if not out of an F body?

 

And how would I ID the prom on the PCM? Im not very firmilliar with this vintage of car yet I work at a Hyundai shop where there is a 30 digit code that you need to break down to figure out what PCM it is. Is this stuff like that too?

 

Fbodys are the only ones with the TPI harness useful to you. The only other car to get the TPI was C4 corvettes. Their harness is completely different

To ID the ECM, read the service number sticker on the case. The last 3 digits identify which it is. 165 is the older MAF ECM, 730 is the new SD ECM. They are not interchangeable and must come with the matching harness

Once you've got the ECM and harness, pop the inspection plate off and look at the PROM/MEMCAL. Its blue/brown

Peek in through an access hole in the top of it and read the 4 letter ID. Check that against the known PROM codes. They are matched for engine and trans, so there will be quite a list. Check out the ECM forum for help on those

 

Oh geez. I have a funny feeling I will be draging home the wrong PCM haha. And making sure I understand. The PCM and harness need to be from the same car AND match the engine I am getting? This could turn out to be one hell of an adventure haha

 

ECM. GM didn't use the designation 'PCM' until the LT1 engine was released, IIRC. GM LOVES to changes things and it's hard to keep up.

Jake

 

Why don't you ask them which car the engine came from, and go pull the stuff out of it?

 

sorry I work for Hyundai and its just habit haha

Im going to try but they have a crusher and alot of times they will pull the power train and crush the car the day it comes in so its a 50/50 shot if the car is still there

 

LOL, no problem. Wish I had a dollar for everytime something like that has happened to me.

Good luck.

Jake

 

Seems counter productive. Lots more parts on a car besides the drivetrain

 

I know, I have asked about it and they said they rotate inventory on cars that get picked over from time to time but not too often. I think its stupid as all hell to crush though

 

As mentioned, the easiest way to tell is to look down behind the left head. The block will be grungy, but under the grunge it will either have a cast-in "5.0LG" or "5.7LG" which is visible from above.