Has the LT4 intake manifold yielded any hp gains over the LT1?
 

Just wondering if it was a worthy investment. It doesn't seem to me to be that different from the LT1. Has anyone ever dyno'd them both on the same motor so see if there was any diff?

From what I understand, the LT4 intake manifold will not match up to the LT1 heads. So it wouldn't really be possible to do a comparison that way.

People have seen gains from LT4 heads + LT4 intake manifold.

Yeah...the size and shape of the runners in a LT-4 are completely different from the LT-1. With enough RTV and creative thinking, you could get the combo to work together, but it would be like having a football bat. Of course the LT-4 Heads and Intake were developed for the grand sport after the LT-1 was in production, so it is going to logically make more power. But the one of each thing isn't going to work for anything.

I wouldn't go to the extent of saying that they are completely different. They are more similar than they are different; the only difference is that the LT4 manifold has .100" higher intake runners than the stock LT1 manifold. It's nothing a little port-matching couldn't take.

It's not plug and play by any means though, nor will it net any HP over stock. But it sure looks nice. :)

Football Bat...HAHAH good one

It'll give ya somewhere in the neighborhood of 5-10 hp alone

How?

The manifold will not physically bolt up due to inteference, but the the ports themselves, would/will line up just fine.

Head or intake? Shape no, but size on heads is a little larger and slightly elevated. Size and location on intake are virtually identical. Actually, earlier (92-95) LT1 intakes had larger port openings.

With enough RTV and creative thinking, you could get the combo to work together, but it would be like having a football bat.

Got a kick outta that one. LOL

Of course the LT-4 Heads and Intake were developed for the grand sport after the LT-1 was in production, so it is going to logically make more power. But the one of each thing isn't going to work for anything.

What they were developed for, and what they were used on, doesn't have to match. It is difficult to believe the LT4 intake plenum/manifold was an engineering decision. There are incompetent people with engineering titles floatin' around, but don't believe many are at GM. No, gotta go with that piece being a bean counter decision.

Untrue/inaccurate statement! There is ample material to raise the port, but oem as cast, it is not.

Hmmm...maybe my source is wrong then?

http://www.fbodythunder.com/ramair95...h/lt4manif.JPG

:(

Your statement was in regards to the intake, not the heads. Correct?

How the hell did I miss that? ;)

Good call arnie. :D

My bad...What I had meant to say by the size and shape being completely different wasn't accurate. The shape is similar, but the size is where the real problem comes in. I got the harsh lesson on that by trying to mix and match the LT-1 and LT-4 stuff back when I was doing upper end stuff on my LT-1. I wasn't happy with the Fel-pro "performance" intake gaskets, and inadvertantly ordered the LT-4 intake set. Imagine my suprise when I've got RTV oozing out of the tube, and I'm trying to set the gaskets in place without disturbing the Most important bead at the back of the intake. So it's then that I find....why doesn't this fit right....the openings of the runners are so large on the gaskets, that they stick out past the edge of the head into the lifter valley! "What vacuum leak" you may ask. And even then, the top side is so long, that they don't sit flush on the head. So that is why I made that statement. I have never tried to put on an LT-4 intake onto LT-1 heads, but if runners are close to the size of the gaskets....I don't see how it could work. If it did...the turbulence and affect on the port velocity couldn't be worth much power, if any.