Beside the red powdercoating, how do you determine which is which? What is the casting number on the heads and intake supposed to be?

 

I don't know any casting numbers or anything, but the intake runners are raised. You'd notice it when set side by side with a LT1 intake.

 

So what would I look for? I feel stupid asking, but where are the runners?

 

LT1 part # = 12552137

LT4 part # = 12550630

The "runners" are the intake passages in the heads - rectangular openings. On the LT4 heads, the "raised" or higher intake runners are fairly obvious when you compare them to the LT1 heads. But on the intake manifold, the difference in height is not as great, and it is harder to tell them apart, without the red paint.

Search for a post on the LT4 intake by "Arnie"... he has provided actual measurements and appearance differences.

LT1 vs. LT4

 

....look for the magic number 12550631.

 

I'm starting to think that I do not have the heads and intake that I thought I had. But I'm not sure yet, I guess I'll have to look for the numbers and see what's going on. Will the stock valve covers fit on a set of LT4 heads? And..... Would you all be able to tell by a picture of my engine bay?

 

You really need to check the part #'s. Yes, stock LT1 valve covers fit fine on LT4 heads.

 

Well, I'm at work right now so I cannot look at the part numbers. I don't think you can, but can you tell if they are or are not from this picture? I painted it this color, but it was the same red that I've seen on the LT4's. I will check part numbers when I get home. Don't crack on the manifold air injector block off, its only temporary

http://www.marines.dyndns.org/Scooby...Z/DSCF0002.jpg

 

Necessity is the mother of invention.