Will these heads work well on a 346 LS1? Will the L76 intake fit a LS1? Is this combo too big for a street car and stock or mild cam?

 

My understanding on this combo is its a no-go because the L92 valvespread may be physically too big for the smaller 346 bore. I haven't tried it to see (running TrickFlows on my 346). The intake rocker is offset to accomodate the 2.160 intake valve and the resulting valvespread. But on the documented end, intake valve shouding is an issue with them on bores any smaller than the 4" bore they were designed to run on. If they actually physically fit, you would have power loss issues from that alone.
Moving to a 6.0 liter stock bottom end is the cheap fix here. You can then safely use the L92 heads and cam to suit.

 

same question October 29th 2007 on this site

"no go for ls1 stock bore
3.898 stock bore for 5.7 ls1
l92 heads require 4.00 in bore minimum
l92 heads are found on iron ly6 6.0 truck engines and 6.2 alloy truck engines
4.00 and 4.065 bore engines"

Next questions:
what cam are you running or thinking of running.
What do you want this car to be street/strip, street fighter, Strip only

Those two questions should let you know where you should go with the cam and heads combo

Is this your first build

 

No, to use these heads you need to have a bore of at least 4.000.

 

Mast Motorsports makes LS3 heads that fit a 3.9 inch bore, I have not seen or heard of any builds using them though. I was thinking about looking into using there LS3 heads on a 346 but like I said I have not seen any builds using them and I'm not going to waste money finding out that they don't make much power over a good set of LS6 heads...also those heads have a lot of intake port volume vs. a LS1-6 head so I would assume you would loose some bottom end power and throttle response.

 

yep, i saw a build with 383 ls1, mast l92 heads, solid roller cam, sheet metal intake...ect. He stated it would pull to 8000 rpms. Idk, i never was it run to back that up.

 

As stock, the L92/LS3 head is designed to breath more efficiently with the bigger bore engine. Look at how they work on the short blocks they are designed to run on and the cam profiles associated with them to get a picture of thier capabilities. This is the reason I suggested the 6.0 iron short block. It would be the cheapest and most efficient way to meet your expectations with these heads.
If it were physically possible to run these heads on a 346, I would seriously consider running the L92/LS3 90mm intake (which you would have to do anyway because of the squareports) and a FAST 90mm throttle body. You would need to run an LS7/LS3/L92 cam profile, appropriate tune, and bolster your exhaust system accordingly. Those issues addressed, you should see substantial increases in power and torque across the board -right off idle.

 

I think SLP sells them for Fbodies but not sure if they are milled to work on the 3.9 inch bore.

 

well I found a small wrinkle, not that I would recomend this, but I did find on the Edelbrock site for the vic jr l92 heads on a small bore motor, you gotta notch the bore.
http://www.edelbrock.com/automotive_...chevy-ls.shtml