I have a 87 GTA and I'm trying to figure out what HP 305 or 350 and possibly the year. Someone swapped the engine a few years ago and I'm having a heck of a time finding parts for the engine. I can't find the Block ID. Any help would be appreciated.

 

My 86 305 from a z28 has block numbers on the back just before the flywheel, you can see it with a flashlight, but I think if you take the valve covers off, you can read the numbers off the heads.

 

Check the pad on the front. It'll be behind the alternator if yours is on the passenger side. If not, just look right in front of the cylinder head/block junction on the passenger side of the engine. It's machined onto a horizontal surface. Just run the codes online.

-Levi

 

What parts do you need? There's very, very few exterior engine parts that are different between a 305 and a 350 for you to worry much about it.

Casting numbers from behind the drivers side head will tell you what the bore is, and the head casting numbers will give you an idea of what kind of potential you're working with. The deck stampings from behind the alternator are nearly useless, they only tell you what the engine used to be, not necessarily what it is now.

 

Are people boring 305s out to 350s? If they are, I haven't heard of it. The pad numbers behind the alternator will tell you exactly the same thing as the ones behind the driver side head, they're just a whole lot easier to get to.

 

werent the 305s the only ones with aluminum intake manifolds?not sure but havent seen one on a 350 3rd gen myself

 

All 3rd gen 350's were TPI, and had exactly the same TPI hardware as the 305's (for any given model year).

 

I have a 1987 with a 350TPI... heres stamp behind the driver side head... not really a casting number per say, unless im missing it.