L92 heads on a 346?
TECH Apprentice
iTrader: (5)
Joined: Dec 2007
Posts: 347
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From: Southern Colorado Front Range
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.
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 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
On The Tree
Joined: Nov 2006
Posts: 168
Likes: 0
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.
TECH Regular
Joined: Jan 2008
Posts: 458
Likes: 0
From: Bellaire, TX
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.
TECH Apprentice
iTrader: (5)
Joined: Dec 2007
Posts: 347
Likes: 0
From: Southern Colorado Front Range
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.
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.
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Brett Foote
On The Tree
Joined: Feb 2007
Posts: 158
Likes: 0
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
http://www.edelbrock.com/automotive_...chevy-ls.shtml
