I was doing some lt4 head porting skimming and came across this article from classic chevy truck.

http://www.customclassictrucks.com/t...ttle_body.html

In the first caption block the guy in the build says the lt4 manifold is the same as the lt1. Has anyone ever heard this or maybe gotten out the micrometer and found the same thing??

 

The guy is full of ****. They are different.

 

i thought so. i have never seen or heard this until i came across this one article.

 

They LT1 and LT4 intakes are the same, except the LT4 intake has a little more meat at the top of the runners. In stock form, dimensionally the ports and inside are exactly the same.

 

They are the same. But different.
Now, thats not confusing.

 

For whatever reason GM didn't match the LT4 intake's ports to the raised ports of the LT4 heads. Even though the LT4 intake had the extra meat to do so.

 

And the extra metal at the top of the LT4 intake's runners interferes with the valve cover rail on the LT1 head, so one of them has to be machined to eliminate the interference, in order to bolt them together. You could get the same results by painting yout LT1 intake red.

 

Can you port match and bolt the lt1 intake on an lt4 head??