lt1 heads intake question
Heads will fit, intake manifold on a 93 is slightly different (fuel rail crossover was at the back).
To keep things simple, you'll want to use a manifold from a 94+.
93 Manifold
94+ manifold
643 casting (93-95) on the left, 561 casting (96-97) on the right.
Both fit, there's just more material in 643s (which also makes them heavier)
To keep things simple, you'll want to use a manifold from a 94+.
93 Manifold
94+ manifold
643 casting (93-95) on the left, 561 casting (96-97) on the right.
Both fit, there's just more material in 643s (which also makes them heavier)
Last edited by James Montigny; Sep 13, 2008 at 03:46 PM.
thankyou james, you said their is a 643,561 casting, is the number stamped on head ?and where would it be? would one be better for producing power over the other? are there any differences in holes for accessory's?
They produce the same amount of power. The holes and passages are the same.
The earlier castings included unneeded material, it was removed in later castings, making them lighter.
Some have speculated that earlier castings (with more material) are better
for porting. I'm not sure that that is truly the case. It you look at the pics
above, you can see what material was removed in the later castings.
It's not like you're going to expand any ports into that area.
Here's an L03 head and it's casting number for reference.
