BigTex

iTrader: (16)

After reading through this thread, I had questions when several people commented that his TR224 cam was too small for his PP stage II LS6 heads:
https://ls1tech.com/forums/generation-iii-internal-engine/148216-results-head-cam-install.html

OK, so whats behind the comments that the cam was too small for those heads? I understand runner volume should affect charge velocity, and that velocity will directly have results on low end torque, power and throttle response. Bigger cams should make more power, but 18 months ago, the TR224 was considered large.

On one hand, I was thinking that if a good set of heads flow considerably more CFMs through all lift points on both intake and duration, that they would enhance just about any cam.

On the other hand, I can see that if the heads have much larger runners that a big cam with long dirations will have a better chance of increasing velocity and packing more charge in per cycle.

I'd like to hear opinions on running a good set of sgt2+ heads on a relatively mild cam (say a FMS 224 .586). Obviously, the heads will support a larger cam and higher lift, and make more power. What will low end torque, under curve power, and peak numbers do with that cam on those heads?

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I have been thinking about going with a set of TEA 2.5 LS6 heads, but running a smaller duration cam with high lift. In my 6 liter truck, I need a good mix of power and low end torque. Those heads may top off a budget stroker someday.

Richard

SPANKY LS1

iTrader: (24)

Poor heads often "need" a big cam (>230 duration) to prop them up some, while good heads all perform just fine with a small cam. It is often a "crutch" used to justify weak HP and TQ numbers. I tend to think that there is no such thing as "too much" head. Look at some numbers of different heads, AS, TEA, MTI, and Cartek all have 450+ rwhp cars with cams <230. If you remember JPRs heads from a year or two ago, he was routinely hitting 420+ with S1 heads and 224 cams. With 224/224 cam only cars routinely putting down 390-410 rwhp, it makes one wonder how a set of "LS6" heads and the same cam can only put down 391.......

Shawn

98SS Blackattack

That car did dyno low. But i think the heads were overkill.A set of 5.3 stage one heads would have done the same if not better.

Linear Velocity

iTrader: (1)

As long as the lift is there to support the flow of the heads, it shouldn't really matter how big or small the duration is; granted you will generally make more power with more duration but the many thing when matching heads and cam is matching the cam's lift with the peak flow numbers on the heads, hardly rocket science. Speed Inc. had an LS6 cam with 1.8 rockers (.600 lift) and stage 2 Ls6 hads and made 420 rwhp on their Z06 with headers, not bad for a completely stock sounding cam I'd say.

98SS Blackattack

I agree, if the tr224 would have had .600 lift his numbers would have been more on target

foff667

iTrader: (2)

not to get off topic but i totally agree with this

pekkaz

For a given cam and engine displacement it is possible to overkill with port volume and valve size. Large port volume works only at high RPM and if the cam does not well support the RPM range there is the bad combo.