i recently bought an '89 IROC..... it's a 5speed, so i know it was originally equiped with an LB9...

but... i suspect that one of the previous owners may have swapped in an L98.... is there a casting number or something that i can look for to find out for sure?

or is there another way to tell which engine it has?

thx for the help guys

 

Ther eis a seven- or eight-digit casting number on the rear ledge of the block casting, near the distributor. Get the number and check the data at www.mortec.com

 

cool.. thx

 

It may even say what engine it is by the casting number. I have a block in my basement that along with the casting number says GM 5.7L.

 

Everyone hopes that the 305 car will turn out to be a 350. But it will not happen 99 44/100% of the time. One sure way is how does it drive.

 

what makes u think its a 350

 

i'm in the same situation.. my vin says l89 but i'm just curious ... i found a number on the front drivers side of my block.. it's 638 can that identify my engine??

 

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


That is what www.mortec.com found for the last 3 digits that you gave, so it does show the correct block for the year.

 

the easiest way is to do what viprklr says. Get a flashlight and dig down past the wire harness on the drivers side of the block just in front of the transmission bellhousing. It will either have a 5.0 or a 5.7 on it. You can check numbers if you want, but that is the easiest/fastest way.

 

thanks for the help

 

well, i'm not a pipedreamer.. i can afford a new engine... but why buy one when i allready have one to work on?


how should i know the difference between the way the torque feels with a 5.0 vs. a 5.7....

it drives good, gobs of torque but not much top end to speak of... i also have a 2000 LS1 Z28, so that's my only basis of comparison

the tacometer is wayyyy off so i can't tell you where the power is in the RPM range... the tac says that it idles at like 2500, and the needle is out of range pretty much anytime i get on it