i just paid for my LQ9 shortblock and im planning on L92's for it. now, what would kill down low with those massive intake/exhaust runners and huge intake valves? im also wondering how the charecteristics of the intake runners will effect the cam specs chosen?

 

It is hard to choose a cam for a set of heads and intake that really haven't had any testing. It is a trial and error game. What size motor, compression, vehicle, transmission, stall will all be factors also.

 

t56, 6.0 (364ci), 89 rs, 10:1. 260cc intake runners, 90cc exhaust, 2.16" int valves, 1.60 (1.59 reall but yea) exhaust valves. as good time as any to discuss this..

 

A high lift ( LSK) 242/248 on a 110, something along that range.

 

i was almost thinking some sort of split would be a the thing to do because of how big the int valve is

 

A traditional slit? Good thinking. All of the L92 intakes should flow very well. L92 exhaust ports could use better flow though, and if you're running a 1.75" primary you might benefit from opening the exhaust sooner.

Ben T.

 

well whatever would get velocity up on the intake side. granted i dont know if it will be an issue yet but it makes sense. for all i know it could love a big reverse split
well hell, how do the LS7's and C5R's react? it would be safe to assume these will react similarly to those.

 

I would go a few degrees less because it's still only 364 cid and it will be hard to get compression up with a stock piston and 70cc chamber. Plus if you want down low power you don't want to go too big. Probably a 232/240 on a 110 lsa. would work nicely with your setup.

Maybe try milling those heads .030" or so to get compression up. You would probably have to flycut with whatever cam you choose though with as big as those friggin valves are. I haven't measured valve drop on an L-92 head though to know for sure.

Nate

 

not gonna mill because later is gonna be FI. that 232/240 sounds like a good canidate. also maybe use an XER/LSK combo with that. lowest i probably should go is like a 228/236-7.

 

I'd suggest 232/240 on a 115 lsa with XER lobes if you're going FI. The LSK lobes aren't really all that beneficial with FI.

Nate

 

Why not give the whole setup picture from begining?
If you are going FI then those big runners and valves will be counter productive,
What you should go after is velocity.
Then you'll need a nice 6* split intake/ exhaust (exhaust biased VE's, with moderate overlap)

 

im going to do fi later, right now the money is going into putting this motor setup together. thats why i didnt mention it at first. am i correct to say that the ramp rates will affect air velocity? if thats so then a high ramp rate and 6* or more split should help get the velocity up there.

 

has anyone bolted l92's on with that big of a cam on stock pistons?
these heads look to be the budget ticket if all is well in valve and piston country.

 

My thoughts as well. I wonder what the CR would be with the large cc chamber. I would like to mill to maintain the stock LS2 CR. I don't know if that will be possible with the cam I am considering. 236/240 .630/.610 111

 

Don't the L92s require a 4.065" bore?

 

They will work with a 4.00" or larger bore.