Rise of the Phoenix

iTrader: (27)

Ok, so lately, I've been doing a lot of research on ported 243/799 heads. For my application, I think this is going to be the route to go. My car is a 2002 WS6, M6, with long tubes, lid, dual exhaust, etc. Basically, full bolt ons. I want to acheive a goal of around 440rwhp and 415 to 420rwtq. I'm about 95% sure who I'm going to go thorugh to get the heads ported, as well as a custom grind cam. Ed Curtis, at Flowtech Induction, not a sponsor on here, is likley going to be my choice. I have confidence he can get me to my goals and I've heard nothign but great things about him. Before I pull the trigger, I have a few questions regarding intake/exhaust port volume. Is my theory correct when I say that the higher the intake/exhaust port volume, the less under the curve power the car will have? Lets say for instance, a 245cc intake and 87cc exhaust set of ported 243 heads vs. a 229cc intake set of ported 243 heads. I would assume the 229cc intake heads would yeild better low/mid range power than the 245cc intake heads, but the 245cc intake heads would be better in the upper RPM's. Is my thinking correct? Land Speed (Brett) offers a Stage III ported 243/799 head that is 245cc intake and 87cc exhaust that uses stock valves. I've yet to speak to Brett, but his website says his street version of the Stage III heads would work great on a stock cub LS1. What do you guys think? My car is a 95% steet car, and under the curve power is what is most important to me. Does it make more sense going with the smaller intake/exhaust runners?

Darkman

iTrader: (2)

http://www.racingheadservice.com/Inf...nnerVolume.asp

http://www.jegs.com/s/tech-articles/...hey+Make+Power

Rise of the Phoenix

iTrader: (27)

Darkman, based on the first link you posted, NO stock cube LS1 should run ported 243/799 heads because ALL ported 243/799 intake and exhaust runners are bigger than that.

Anyone else want to help me out?

outkast6991

iTrader: (34)

Search google for a square port vs cathedral port head comparison written by dennis wheet. Ever wonder how a 265cc port makes so much tq in the trucks? It's a good read

Rise of the Phoenix

iTrader: (27)

I'll take a look at that. So are you saying that a cathedral port heads won't yeild those same torque results when that big? I guess my main question is how much low end torque would you loose going from a 229cc intake port to a 245cc intake port?

SweetS10V8

iTrader: (4)

229cc is plenty for a 95% street driven car. Might give up a few HP up to to the 245s, but the car will feel faster at part throttle, leaving lights at 1/4 throttle, tip ins, etc which is probably 99% of the time you are driving the car overall.

Although I will admit my truck was a 6.0L with a small 219@ .050 cam, and I ran 275cc CNC LS3 heads. Probably could have picked up a lot of low to midrange with a cathedral set of heads. But thats part of the reason I cammed so small, because I knew the heads had huge intake runners.

badazz81z28

iTrader: (6)

What don't you ask the guy working on your heads??? Tell him your goals and power levels... JMHO

Rise of the Phoenix

iTrader: (27)

That's what I'm in the process of doing. Ed Curtis is designing my custom cam, so I'm going to go with is ported 243/799 heads. With stock valves, the intake runner is 229cc. I've done a bunch of research and there have been a few LS1 GTO's with his CNC'd heads and custom cam that have put down 450 rwhp and well over 400 rwtq. Yesterday, I stumbled upon the Land Speed website and Brett's ported 243/799 heads, so I just had a few questions about the intake/exhaust port size in therms of "under the curve power" since they are so much larger. I've e-mailed Brett, but haven't heard back from him yet.

Rise of the Phoenix

iTrader: (27)

Thanks SweetS10V8. That is what I was looking for. One interesting thing about Brett's (Land Speed's) work is that he has the heads CNC ported, then does some additional hand porting/blending as well.

mac62989

iTrader: (1)

I feel like I never see that high of a torque output from worked over OEM heads.. Even just recently in the dyno section there was some on LS2s that had 47x rwhp and barely 400 rwtq.. Thats with a lil more cubes than our LS1s..

outkast6991

iTrader: (34)

here's the article. it's a good read

http://www.grab-a-lane.com/forums/sh...at-information!!!

dr_whigham

iTrader: (49)

Not to butt in here, but it's always been my understanding the square ports (LS3) are better for upper RPM, but give up low end, and vice-versa for the cathedral ports.

My WHOLE reasoning for wanting to go with a cathedral head.... 99% street car.... Paired with my custom Ed Curtis cam.

outkast6991

iTrader: (34)

I'm not suggesting that square ports are the way to go for the op. if you read the article the point I was trying to make is that runner size has little to do with a good decision on a cylinder heads. I would take a properly done 240+ cc head over a lesser quality 220cc deal

dr_whigham

iTrader: (49)

I understood that. I was simply throwing it out there for debate, and to ensure my line of thinking is correct.

I've got the same ?'s as OP.... but I think I've made up my mind on the AI 226's. Phil and Ed do collaborate together with heads and cams on occassion. The dyno doesn't lie.

SWEET98SS

iTrader: (8)

I went from the streetsweeper to having AI port my 853's, there 219 cc HCR porting, and a 230, 238, 600, 600 113 cam. The car drives pretty darn close to stock, can use 6th gear again, no surging, tons of power. I will post up the dyno numbers once I get them.

427LS7HCI

AI uses a 226, TSP uses a 225 and TEA uses a 220 intake port volume on their 243/799 heads.... 245cc intake ports would be major OVERKILL!

Rise of the Phoenix

iTrader: (27)

I'll be anxious to see your numbers. I've fully decided to let Ed do the who combo, heads and cam. Since they are his heads, he'll be able to design the cam around them and make a killer combo. Can't wait. Now, just need to find some used 243/799 heads.