I am trying to determine if my motor is a 305 or 350 for my 87 Iroc z TPI. I looked on the back of the block by the drivers side and I can't seem to find it. Wires are in the way And I tried to feel for it and I got nothing. Am I looking in the wrong location? Any tips or tricks to find the number?

 

Either side of engine here ( varies with engine age )





ID Numbers from this location also , the 2 or 3 letter code tells exactly what the engine WAS when it left the factory years ago.
What it is now after many owners is a completely different story

 

How can I get back there? There is so much st puff in the way I don't want to damage anything. Any tricks with a mirror or something?

 

Bend over and look. Not rocket science here; just a car.

If you REALLY wanna know, you'll figure it out.

His first pic is BY FAR the easiest way to be CERTAIN. I'd advise against wasting any effort on the 2nd one.

 

Said I was having a hard time looking bc of the wires in the way. I don't want to break anything. The wire are very thick and hard to move. I was just wondering if there was an easier way of getting around it without doing damage to my car.

 

Said if you wanna know, you'll figure out a way, instead of P&Ming about "hard".

We're supposed to have a pair in here. Even the occasional female among us usually seems to.

 

I just asked for some help there is no need to criticize.

 

No need to complain about "hard". Just look.

If it's any comfort, it's the same for all the rest of us too. Either we wanna know, or we don't. If we do, we do what it takes. In this matter, and every other matter as well.

 

Not conclusive, but pulling a valvecover and getting the cylinder head casting number can tell you what it might be. How accurate that is depends on the likelihood that someone would have changed out the cylinder heads at some point. If it's a 10k mile completely stock car, probably very good indicator. If it's a 250k cobbled together car, not so much.

I tend to think that most of the time if the TPI is still on it, the heads are probably what came on the block. But the only way to really, really know for sure, is to look at that spot that's hard to get to.

But 083 heads came on L98 350's, and 081 heads came on LB9 305's. Things happen and heads get swapped around in strange ways, even replacement engines have been known to show up with different heads on each side, or the wrong ones. But getting that number is a clue. If your vin number agrees with what your head casting numbers, that's another small clue.

But the only way you'll ever know for sure is to look at that number on the back of the block or to pull the heads off and measure the cylinder bore. If you can deal with "probably a [whatever]...", then pull a valvecover and check the vin number. 8th digit is an F if the car is a factory 305 car, 8th digit is an 8, it's a factory 350 car. But that doesn't tell you what's currently in the car, just what came in it from the factory.

 

I tried looking again today. The space between the firewall and block has wires and tubes and I don't have enough space to move it around. i can barely get my hand in there too. That's why I am having trouble finding it. I am going to do a head gasket change soon so I guess I will figure it out then. Also I check the number on the fuel injectors (5235047) and I have some original parts bc they have the dates from 86 on them. My car originally came with a 305 and I just want to make sure bc it had a few owners and somethings where changed. I also found a air horn on the bottom of the car but it was disconnected lol. I just changed the exhaust, from y pipe to the mufflers (Magnaflow cat, flowmaster exhaust) Some sensors, put in MSD distributor, air foil. She has been much more responsive and pulls harder. Sometimes I dont even give it full gas the the tires chirp. One of my friends think I might have a 5.7 but I keep telling him its a 305.