Im going to look at a 86 with a 88 5.7L IROC engine. How do I tell if it is a 350. I know the 305 and 350s look identical.
Thanks for your help!!!

different harmonic balancer (minor differences)

decode the VIN on the block to see what it really is..

use a flashlight and a pocket mirror and read what's stamped on the driverside rear of the block..

here's an example of where you'll find it..

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Webmaster: www.IROC-Z.org & www.GMPerformance.org

Look at the VIN and find out if it came with a 350 and look on the front of the engine one the left side on the upper block and see if the numbers are in the VIN. That’s how i did it and found out that mine didn’t have a 350 like the people said that it did witch i did not really think it did.

It didnt come with a stock 350. He put a 88 5.7L Iroc engine in it. It originaly came with a 305.

Im still lost, can someone explain it maybe easier? Im a total newbie.

But thanks for the help so far!!!!

alright, let me point out my picture..

the top half is hard to read but it shows the VIN of my car. If you decode that number (located on the passenger side of the block on the front of the head) it will tell you the displacement of that engine.

That number won't match the VIN of your car, obviously, but you need to decode it. It will tell you what car it came in, and the displacement, also the build number.

The bottom half is a shot of the rear of the engine, the 5.0L is on the driverside rear of the block. Like I said, you'll need a pocket mirror and a flashlight to see it because you can't see it in the car.

I hope I cleared that up for you
ttyl,
Colin

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Webmaster: www.IROC-Z.org & www.GMPerformance.org

while wre on the topic, whats the diff with the L69 and the LG4 305's?

I have an 84 with the L69 in it and I wanted to know if its anything special.

I know the 8th digit on the vin # will tell you what motor the car came with. If it is an 8, it is a 350. But like the other guys said, you need to check the block, cause it might be a different motor.
Take care
Mike

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(Gran Turismo Americano) "The Ultimate Firebird"
Smokin 1989 GTA- Bone stock except for exhaust. (no catalytic-stainless pipe into Flowmaster 2 chamber).

Thank you for the help! You are soooo friggin awesome!!!!!!!!!!!!

"but you need to decode it"

How would I do that?

Thanks again!

lg4 is standard output 305, l69 is high output 305. the l69 305 actually had more horsepower than the 350.

what does it mean to decode the vin? the vin is basically a code. the 8th digit tells what engine is in the car. the block identification # is a different code, but you can figure out engine specs from that code.

or u could just take it for a drive, if u have ever driven a 350 or 305 before, if he says its a 350 u should be able to do 0-60 in like 6.4, but thats just the fun way to test it.

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88' GTA 350 MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass

Yea Ive been in a 305 and a 350. I hopefully could tell that way too along with codes.

His car is modded out big time. I hope I can get it.

not necessarily, my '86 drives like a 350.. why? it has 4.11s, and I had no idea it did until a few weeks later when I started wondering why it would rev 3000rpm at 65mph in OVERDRIVE...

the only way to tell for sure is by the block..

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Webmaster: www.IROC-Z.org & www.GMPerformance.org

you'll need to either bring along a book with you or call the guy first and email me the VIN that he reads to you off the block.

i'll decode the VIN off the block, tell you where it's from and what the displacement is

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Webmaster: www.IROC-Z.org & www.GMPerformance.org

Cool Thanks! Will do!

sweet