L92 Heads/Intake - Cam Question
Originally Posted by carado1984
can someone please clarify the head numbers for me.. so the 853 and 241 are both ls1 heads? I know the 243s are ls6 heads whats the difference between the first two and between those 3, the l92 and the 5.3 heads, which have the most potential?
Originally Posted by HEMIETR
L92's have 2.16 intake valves which will have PTV issues unless the pistons have valve reliefs cut in them.
Originally Posted by Quik
what if you run them on a 408 with -13cc reliefs and a cam similar to the Trex but with a 112+2 lsa? how well will these do with this cam and motor
Originally Posted by Quik
what if you run them on a 408 with -13cc reliefs and a cam similar to the Trex but with a 112+2 lsa? how well will these do with this cam and motor
Originally Posted by Quik
what if you run them on a 408 with -13cc reliefs and a cam similar to the Trex but with a 112+2 lsa? how well will these do with this cam and motor
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Brett Foote
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There is an interesting article in the last popularhotrodding mag I think its onsite for reading too, on head design. Basically with high compression engines exhaust valve size is less important as cylinder pressure drops fast with high compression so most exhaust work is done sooner. Therefore you can open the valve sooner in the power stroke without robbing too much power. Also I guess part of the reason why cam timing is the way that it is with the ls7 series. I think its designed that way as the intake valve is normally the one that needs crutching not the exhaust!
Originally Posted by ringram
There is an interesting article in the last popularhotrodding mag I think its onsite for reading too, on head design. Basically with high compression engines exhaust valve size is less important as cylinder pressure drops fast with high compression so most exhaust work is done sooner. Therefore you can open the valve sooner in the power stroke without robbing too much power. Also I guess part of the reason why cam timing is the way that it is with the ls7 series. I think its designed that way as the intake valve is normally the one that needs crutching not the exhaust!
I think your cams going to leave a lot on the table with a L92 head, even on the 4" bore the heads will want some split. Nothing crazy like a stock LS7 head but a lot more than we are used to with the LS1/LS2 stuff.
Bret
Bret
Originally Posted by ringram
I think its designed that way as the intake valve is normally the one that needs crutching not the exhaust!
Ben T.
Uh, no that's going to be off.
TBSS? I'm getting lost in the nomenclature but that's a SS Silverado 6.0l? I'd use the L92 intake along with the heads and a much smaller cam than was suggested.
Bret
TBSS? I'm getting lost in the nomenclature but that's a SS Silverado 6.0l? I'd use the L92 intake along with the heads and a much smaller cam than was suggested.
Bret
Originally Posted by SStrokerAce
Uh, no that's going to be off.
TBSS? I'm getting lost in the nomenclature but that's a SS Silverado 6.0l? I'd use the L92 intake along with the heads and a much smaller cam than was suggested.
Bret
TBSS? I'm getting lost in the nomenclature but that's a SS Silverado 6.0l? I'd use the L92 intake along with the heads and a much smaller cam than was suggested.
Bret
These things aren't going to need intake duration, and until you get flow numbers on a 4.0" bore your not going to know the split. Even then they will still want more exhaust duration than that. These heads are made like any good NA race head, HUGE intake valves, as big as you can get in there and small exhaust valves. We are talking a diameter/circumfrence ratio of 73% compared to 77% in standard LS or SBC heads. When we get flow numbers on the smaller bore and with intakes and exhaust pipes then it should give us a better indication of how much split, but even so it's still going to be more than 10 degs difference at .050", so the traditional LS cams will not give the best results.
Bret
Bret