Goosecaddy05

is there a cam similar to the tick stage 2 ls7 cam for big cube cathedral port engines or do you just have to go custom?

DietCoke

iTrader: (18)

tsp's texas giant is a great small-midrange stroker cam.

Mazzenger

iTrader: (5)

You might check out the 408 sticky in the dyno section and also talk to TSP. I am sure they know of some combinations that work well with the PRC 237 heads.

Sales@Tick

iTrader: (3)

From what you've described, I would suggest a custom grind. Something similar to these:

239/246 .624"/.595" 114lsa

243/248 .624"/.595" 113lsa

If you want the best drivability possible with the ability to make 500rwhp the 239/246 114lsa profile would be my choice.

If you want to sacrifice some drivability with the ability to make more than 500rwhp the 243/248 113lsa profile would be my choice.

I wouldn't use the Emissions cam or Stage 2 LS7 cam in this application.

chevyrunner

iTrader: (4)

martin whats the benefit of a reverse lift came, such as 6xx 5xx as opposed to a even cam such as 650 650, or something like a 61x 62x set up?

Sales@Tick

iTrader: (3)

In my opinion it comes down to lobe selection and selecting the proper valve events at different lift intervals as to why I specify my cams with less exhaust lift. I also prefer a milder exhaust lobe which normally a milder lobe has less lift. Not always, but most of the time.

I don't feel exhaust lift is nearly as important(it's still important) as intake lift since the exhaust lobes job is not to fill the cylinder.

Exhaust is pressurized at a very high PSI. Much more so than the intake charge. Because of this it does not need as much lift to clear the cylinder as the intake lobe does to fill the cylinder.

Two totally different roles.

chevyrunner

iTrader: (4)

martin that makes sense, however in what kind of set up would you want a big spread btween intake/ exhaust and lift? nitrous setups?

Sales@Tick

iTrader: (3)

I honestly just don't look at it that way. Whatever it ends up being with regards to the combination is what it is.

I'm much more concerned with lobe area then how much "spread" there is between intake and exhaust valve lift.

Goosecaddy05

thanks a bunch Martin, you've been a great help and very quick to reply to all my questions, I'm gonna go with the 247/250 .624/.595 114+4 cam you recommended... I'll be sure to post the results after

Goosecaddy05

instead of the prc 237s i'm going with 247s since my bore supports them and they are the same $

Sales@Tick

iTrader: (3)

I just had another customer with a 408, PRC 237 heads, Fast intake in a 6 speed GTO make 537rwhp/515rwtq with a more aggressive version of this cam. His cam specs were 247/251 .624"/.624" 111lsa.

I would expect your slightly larger engine and slightly larger heads even with a more docile cam to make similar power.

Goosecaddy05

that would be great!!!! although i feel i have a huge drivetrain loss even with a six speed. my stock ls6 put down just 300 hp on a dynojet in fl once. but it did manage 320 with a cai untuned.... but taking into account c5 zo6s have made 360 stock i'm gonna be etremely happy to get above 500 even if just a little, the setup i have now is a ls6 with cnc ported and extremely decked 317s that i had to shave down the underbelly of my ls6 intake before going to my fast to get it to fit. the ls6 intake would rock on the heads they are decked so much.... i'm actually not sure what my comp ratio is on the current motor... the cyl pressure is 235 in each cyl in a comp test and i have been told that it is 13.5 by one shop, but since they are 317s i find that hard to believe considering the cam i'm running even taking into account the people who put the cam in told me i'll have marks on the pistons afterwards.... even with this setup the car only makes 430rwhp, the 455 in the sig was a cold run fluke so i'm really looking forward to the results of the cam you rec'd

chevyrunner

iTrader: (4)

martin how do these prc heads flow compared to ported stock ls3 head? if i had 823 heads which are ported would i gain noticible rwhp/tq by switching heads ? or are 821s good enough?

Sales@Tick

iTrader: (3)

I would estimate the ported LS3 heads to flow a little bit more, but that is going to be determined by what flow bench, what test parameters are used and who ported them.

With a OEM style(Fast included) manifold I prefer a cathedral port cylinder head.

chevyrunner

iTrader: (4)

wow i thought the the ls3 square port was way better that cathedral port.. what cathedral port flows better than a ported set of gm ls3 heads?

and to verify the small bore ls7 heads flow the best out of all 3 right, make the most power?

Sales@Tick

iTrader: (3)

I never said they flow better.

I could honestly care less about flow numbers and using that to determine how much power a certain cylinder head is capable of producing. I'm much more concerned with port volume, cross sectional area and valve diameter/area. Much more so than how high can a company inflate their flow numbers using test parameters that will never be seen in the real world.

chevyrunner

iTrader: (4)

lol, my apologies didnt mean to imply that you said that, was i correct however about the ls7 small bore (for motors such as 4.0-60 over motors) being the best head choice? albeit expensive

Sales@Tick

iTrader: (3)

No problem my friend!

I wouldn't use a small bore LS7 head unless the bore was 4.030" or larger and preferably 4.065" and larger.

You have to look at the port volume and valve diameter versus the operating range of your engine.

IMO there is no need for such a large port/valve combination on an engine that cannot turn more than 6500-7000rpm while efficiently producing power.