trxman

I'm doing a ls2 build with a four inch stroke. I was going to put the ls3 heads and intake on but I think that's going to hurt my wallet too much. But I also think a set of cnc ls2 and going to be big money. I don't know what to go with

John

cfn101788

Im in the same boat as you man. I was thinking LS3 heads or Trick Flow 235's. BTW could you tell me what pistons, rods, and crank you're using?

FlamingTA

iTrader: (8)

If you look at just flow numbers the ls3 stuff looks very good, and they are. But if you are street driving it's still hard to beat the cathedral port heads. The smaller intake port volume can make for some very good port speed and can make the car just snappy when you roll into the throttle. For good numbers on a budget, some ported 243's by the big names are hard to beat. AI, WCCH, TEA, etc.

02blackbeauty19

iTrader: (22)

I'm in the same boat myself.

I read where guys say that the rectangular port stuff is the cat's pajamas. Others rave about the under the curve power that the cathedral port stuff puts out. I read something recently where someone said that the people who recommend the cathedral port heads are either selling them or have no experience with rectangular port heads. That statement does hold some water in my eyes...

FlamingTA

iTrader: (8)

Yes and no. The rectangular port heads do perform very good. But you still can not get around the facts. With a very large intake port volume you can have some super good flow on the top end of lift more potential HP. The better way of looking at flow numbers on a head is average flow. Add up the 100, 200, 300, 400, 500, 600, 650, 600, etc.

2 heads. One that flows 350cfm at 650 with 275cc intake port size. 2nd one that flows 330 at 650 with 225-230cc intake port size. 2nd head will probably flow about 10 or more cfm's more then head 1 from 100-400.
Most ppl looking at those will probably look just at the top end flow and pick head one. The racers will most likely pick head 2 because with the average numbers it would actually be faster.
Now these numbers make some assumptions and it's really up to the way you want to run your setup. It's also not like it's a win or lose decision, it's more of a good vs good. Just more along the lines of what would work better for your setup.

02blackbeauty19

iTrader: (22)

^ I see what you're saying.

How does each perform when boost is thrown in the mix?

trxman

k1 4.000" crank and k1 stroker rods with arp 2000 bolts. pistons are going to be wiseco's either -2.8cc or -8cc...another decision i have to make. Ive read that the ls3 top likes alot of timing so I would need to keep the compression down. I can get ls3 bare castings for like 200 a piece and through stainless valves in em with a set of springs, retainers, and locks and mill them then get a stock ls3 intake. If I went with the ls2 heads I would probably have to get a nice FAST intake and TB and i think the price of that would be more then the ls3 set up.

FlamingTA

iTrader: (8)

I have not run boost before so I'm not as sure on it. I know that boost makes heads not as big of a deal. With boost you will want a thick deck, TFS, AFR, All-pro, etc. The TFS 220 seems to be a good somewhat inexpensive choice for heads on boost.

FlamingTA

iTrader: (8)

If you are going that route then it's best to spring for the hollow stem valves. The 2.16 stainless valves can get real heavy and you will have issues with valve control with alot of the modern lobes. Also, don't look solely on the head flow. Most ls3 heads are flowed on a 4.065 or 4.125" bore. You will have some pretty big valve shrouding with only a 4.005" bore.