WhiteChevy3

Thinking of going to l92 heads on my lq4.
My lq4 currently has stock 317 heads, 226/230 @600. 112+4 with a tbss intake and 90mm tb.

Thinking of going to L92 heads and l92 truck intake and milling the heads .030.

What u guys think??

Vortec350ss

iTrader: (20)

You will also want a new cam that will favor the exhaust a little more with the L92's.

IMO if you are doing a head swap, and changing all that other stuff, you might as well stick with the cathedral heads and get something that will outperform the L92's.

Seems like a lot of hassle for not a ton of gain for that swap IMO.

Mikey 97Z M6

iTrader: (35)

Have you calc'd out the compression ratio with those dished LQ4 pistons? Seems like even if you milled the heads .030 the compression wouldn't be that great. I milled some L92's .030 and paired them up with some flat top pistons and got 11.3:1 so with a dished piston I think you'd be lucky to get 10:1.

Mike

Blackpanther99

iTrader: (8)

If your going boost YES the L92s are worth it, otherwise dont even bother getting them. Stay with 317s.

dirt track racer 81

iTrader: (45)

Milling them .040 will put you at a 64cc chamber. I had a cam that I was told was a bad cam 244/248 .612/.615 112+2 for l92 heads and I went 10.64 in an extended cab truck in my old 10.6:1 compression motor. New motor is 11.8:1 compression and has a cam for these heads. 251/267 .623/.623 115+6 and I only gained 20hp..

So saying you have to have cam for these heads to work is irrelevant IMO.

I wouldn't hesitate to swap to these heads.

WICKEDOWESIX

iTrader: (2)

IMO L92 heads in a 4" bore shroud the valves ( hence why they are in a 4.065" bore). Stick to some ported cathedral heads.

GREENSIERRA

glad this thread came up, I have a brand new rec port TBSS intake kicking around and just bought a LQ4
was debating on either putting my 799s on or getting a set of L92s
hope this thread makes up my mind

dirt track racer 81

iTrader: (45)

Your going to spend over twice as much on a ported set of heads than going with l92 heads to make the same power..
On my old 370 I picked up 45 hp going from 243 heads milled .030 to l92 heads with a cam that's supposively not for l92 heads.

hog

The L92 heads do come in 4" bore application stock. LY6 etc.

peace
Hog

Mikey 97Z M6

iTrader: (35)

If your intake has rectangular ports then you must have a L92 truck intake, not a TBSS intake. To my knowledge TBSS's never came with rectangular port heads, only cathedral style.

Mike