LT1TA

iTrader: (17)

LQ 408 twin turbo, cr about 9.3:1
cam is a 236/240 640/620 115+4


Here is the issue, I am thinking about changing my turbo setup. I currently have unported 317s with valvetrain upgrades. vic jr and fast 92 tb.

I am only interested in stock l92 heads as I am not trying to invest money into the heads when i have other areas of concern and a very recently limited budget. I will likely sell the entire top end and put it towards the l92 swap, but I need to be sure this is going to be worth the money and time.

I know the 317 heads have an i/e% of 73% efficiency and the l92 has about 65%. But even with the more efficiency out of the 317, the l92 flows more which will give me more power advantage then the exhaust issue will cost me. So that part i'm leaning towards the square port.

Being that the l92 has so much more intake flow than exhaust, is the lift on the cam going to aid that problem more or am I reading the cam specs wrong?

Thanks in advance.

Blackpanther99

iTrader: (8)

The 317s ported should be pretty good already. Switching to L92s wont be a bad idea also, but then again you could have clearance issues with your current cam. (not a expert)

LT1TA

iTrader: (17)

the 317s are untouched, just have upgraded valvetrain

im so indecisive. Last night I was pending sales with new lsa heads, some like new ls3 heads or some tfs 235s. I went with the tfs heads. Just going to take a little longer to finish the build but there is a lot of peace of mind and power gains by the decision imo.

rpturbo

iTrader: (47)

I am waiting to see what some experts say on this. I think those LSA heads flow really well and would be a good idea. I am not sure about the lift on your cam with them though. Duration looks good IMO. That BER LS3 intake would work great with that combo.