What is the difference between and LT4 & LTI intake manifold?

Beside the LT4 being redi is there any difference?

Will the LT4 intake manifold fit on a Z28 LT1 perfectly?


Thanks in advance :-D

 

LT4 is a tall port head/manifold. The port is .100 taller than LT1.

 

Will an LT4 intake fit with all other stock Z28 LT1 Stock engine components or do i have to upgrade and replace other stuff too?

 

Should match up to everything but the heads. They match up with LT4 heads quite nicely though, so upgrade to those if you want and you'll be set.

I think you can have an LT4 intake machined a bit to fit with LT1 heads, not sure. Or maybe I'm thinking LT1 intake machined for LT4 heads... hmm.

 

Does anyone else have some much needed info?

 

wont work. different intake runner design so it doesnt match up right. its a different angle. well it would fit but you would loose power unless you went with the lt4 heads as well.

 

Is it possible to bolt an LT1 intake to LT4 heads?

I mean I know that the runners will not line up but it is possible, outside of that issue?

 

Yes, a small intake runner to a larger head port well not hurt, but your not getting the full potential of the head.

 

With the abundance of misinformation that continues to be passed along, I felt compelled to respond in this thread. My post is based on actual comparison of virgin unmolested oem castings.

The as cast LT1 port is actually a HIGHER port than the as cast LT4 port by appr. 1/16". Surprising, isn't it? The LT4 casting does have more as cast material above the roof of the port to allow one to raise the port roof a greater amount compared to the LT1 casting. As far as the intake port being a different angle, well a slight amount, yes. However, I give the advantage to the LT1 casting. The angle of the LT1 port is, by a very small amount, angled closer to vertical when compared to the LT4 casting. Another surprise.

Can a person physically bolt the unmodified LT4 intake to an unmodified LT1 head? No! Understand that the intake plenum mounting surface of the LTx heads is machined with a step (or shoulder if you will). This step or shoulder is machined higher above the port roof, on the LT4 head, to clear the LT4 plenum, which has additional as cast material, above the port (as stated above) to allow porting to raise the roof of the port.

Can a person physically bolt an as cast unmodded LT1 intake to a virgin LT4 head. Yes! Will it function flow wise? As effective as the as cast LT4 intake plenum. As stated above, with the raised port, (as cast) even more so. BTW, the port floor of the LT4 intake, at the gasket surface, is actually lower than the mating port gasket surface of the LT4 head. This is a mismatch of bigger flowing into smaller. Not a good idea. Don't believe me? Check and make a layout of the ports for yourself.

Hoped this help dispel some of the misinformation being spread.

 

Yeah

 

everyone should have this page bookmarked:
http://home.tir.com/~steveher/lt4.html

best info for the differences of the LT1 and LT4, mostly in the heads, but lots of damn-good info.

 

glad i ran across this post because it answered the questions i had after trying to fit the LT4 intake to my stock LT1 heads and just like Arnie said it wont work. looks like the LT1 head would have to be machined down above the intake ports to allow the LT4 intake to mount flush with the heads. another thing i noticed was the LT4 intake ports look smaller than the LT1 ports but they have plenty of room to be ported bigger.