Is it possible???

My major concern are the valves interfering with the deck of the block.

 

1. No, minimum of 4.0 bore required.
2. This really isn't a question for this forum.
3. With well over 1,600 posts, it would seem that you would be familiar with search and the fact that this question has been asked many, many times.

I'm not trying to be rude, but with your experience on the forum, I would think that you would be aware of these things.

All my best,

Steve

 

There are people now working on a small bore version of the l92 head. Nothing has been released yet as far as i know.

 

Thanks Steve... I did a search. Simple question... and still not an answer if the valve will contact the deck of the block. I work for a Corvette shop that but unfortunatly we work mostly on 1957-1967 cars. We have just purchased a 1998 for a shop project. It has been several months since I have been on this site. Sorry, but after looking through 3 pages of search results, I thought I could get a simple answer.

I will assume from your post that they will interfere. I can read from GM that they require a 4.000 minimum bore. I was just wondering if anyone had actually bolted these to a 5.7 to verify clearance issues. I can use a smaller valve and new seats if that is the case, just wondering so I can order assembled or un-assembled.

 

You might be able to change the intake seat and use a 2.08 but it would still might hit as the valve stem is physically farther outboard than ls1 heads. Why bother with the l92 head if you are going to shrink the intake valve? Probably why steve was a little snippy.

 

The intake valve is offset so you can't get the clearance you need by going smaller unless you run a really small intake valve.

Marty

 

Thank you... All I needed to know

 

actually the L92 heads will fit the Ls1 block but there is only .020 of clearence between the valves and the cylinder walls.

 

This was the reason I posted this in this section. Exactly the information I was looking for. Thank you!

 

Yep, good info.
I read, earlier in the week....but I think it may have been in the "advanced" section ?, that a valve swap was possible for the smaller (3.900) bore. Little smaller valve and the great rect. ports.
GM seems to be very fond of this head design.

 

I saw in GM-Hi-tech that the General is working on a L92 head to work with the 3.90 bores.

 

Lets say the head would work on a 3.9 bore LS1. The new question will be how would it perform. I will say below avarage at best. You have a head with large intake runner, that starts as a 72cc head. You have a huge number of reasons why this head would make little power on a LS1.
I would bet a LS6 head with a fast 90 would make more then a L92 head and L76 manifold on a stock LS1.
Complete waste of time.

 

...to answer your question guys, the other day I was at the local race engine machine shop. Anyways we threw an l92 head on an ls1 with a 4 inch bore. However we checked the motor for clearances and came to the conclusion that they will fit on a 3.9 inch bore. It will however fit but with very close clearances to the deck of the block. At that point it would not be worth having the heads as they would most likely have a bad case of valve shrouding. Until someone comes out with a small bore design don't waste your breath.

 

What is your opinion on a solid-roller BIG cam, sheetmetal intake blah,blah basically a real high winder, could one expect benefits then???

This is assuming a l-92 head optimized for a smaller bore. (smaller valves, relocated etc....)

 

if you were going to spend that kind of money you are better off going extreme with a really nice cathedral port head

 

lol, some one is stealing my job (search button cheerleader)

 

The sleeve is thin, but if someone wanted to do it, you could notch the cylinder at the top. You have to make sure the notch doesn't fall where the top ring rides, which means it could only be .220 deep or so. bbc 396's were all this way....yes shrouded, but still ran pretty good.

 

I think that you would be better off with a good set of CNC ported heads with cathedral ports the L92 heads will work great on a big inch motor but I do not think a 346 is going to make good HP gains with them ... the runners are to large and the chambers are too...

 

even with a 4.00 bore you have to be very careful with cam selection for the L92. The size of the valve and how LS pistions stick out the hole make for an interesting combination.