misery motorsports

any preference's on cnc ported l92/ls3 heads?
I know there are a lot of company's out there that make them !! I was wondering who has what and wich one should I go with?

pro comp
texas speed
livernoise
????

dogsballs

how much hp you chasing? save $'s just deck them and incrwase comp

misery motorsports

its a ls2 so I have 243 heads but im buying l92 heads and big cam and victor intake and quickfuel 750 carb
im looking for 550 or more but my price range is under 3k so i cant really do stroker or much other than l92 heads and cam
I need to keep reliability and its a off road race truck where my speeds are 40-110 and my rpm range im in is 3500/4000 -7500/8000

3pedals

iTrader: (3)

Darin Morgan does some

newschool72

iTrader: (12)

Ive seen a couple instances where small cube engines lose HP and TQ by porting the LS3 castings. In stock form they are more than enough to get 7500rpms out of a 6.0. If anything, I would have the exhaust port cnced to get a better intake/exhaust ratio and leave the intake port alone. Just have the heads flowed before you have a cam ground to the I/E ratio. The cam will need less of a split with the better exhaust port flow.

Baconz28

Interesting thread. ^^ I'm doing a 6.0 iron motor build but the engine been bored with LS3 pistons and internals.

Doug G

Depending on cam lift....7500 is do-able in stock form.
550HP in stock form as well, wouldn't be all that hard.

Going on the 2.2HP per CFM of flow....600HP+ is possible stock, as-cast.

dogsballs

i'm doing 550+hp, on a alloy 6.0 stock bottom end with LS3 heads unported, but decked 100thou, with 236/246 613/613 110 lsa cam, vic jnr and 1000cfm e85 carb.

newschool72

iTrader: (12)

Bone stock with dyno headers, LS3s often make very close to 500fwhp, depending on the dyno. Ive seen 470fwhp on the stingiest one so far. With nothing more than a BABY cam, 530-540fwhp is done all the time. With a decent bore, the LS3 heads can make well over 500 without any effort and a well speced cam with a carbed intake can do well over 550 at the flywheel, with stock heads. Save the ported heads for something over 400 cid, because on anything smaller you wont see the rpms to use all the stock casting have to offer. I plugged the stock LS3 heads into a formula to see what RPM Id have to turn a 376 to use all the heads had to offer, based on head flow. On my stock cube 6.2 I would have to spin to 8000+rpms for the heads to start becoming a restriction ! Save your money for other parts and run the stock heads, IMO.

jfmoore79

So are CNC'd heads worth the extra $$ on a 408 iron motor with a carb and streetable cam? I have been told that a good aftermarket set of cathedral port heads will make more power than the factory rectangular ports. Any truth to it?

fast89stang

iTrader: (2)

Not to highjack newschool, but what do you think of port work on the exhaust side anyway? I was thinking of doing mine, just a clean up, maybe taper around the guides and such. I never even cleaned the carbon from mine when i bolted them on my motor.

87silverbullet

iTrader: (11)

I wouldn't put L92/LS3 heads on anything with a 4 inch bore. It shrouds the valve too much with the stock valves. If you are bent on putting rectangular ports on there, look into Ballistic speed. They have rectangular port heads that are meant for smaller bores with smaller valves.

At a certain point the motor is going to hit a brick wall because of the shrouding.

That's why LS3/L92 motors do well with just cam swaps and make crazy power. When you look at a g8 it doesn't do as well with the 4.000 bore with L92 style heads.

fast89stang

iTrader: (2)

Mines running 6.3s in the 1/8, I dont know how much more I could expect, but I thought it was doing pretty good for a stock bore with l92s.

newschool72

iTrader: (12)

If I ever pull the heads off my LS3, I will clean the exhaust up. A balanced head should always work better, IMO. Building HP is just about moving more air in the most efficient way. The LS3 head really doesn't have a bad exhaust port. It just has a much better intake port. The more spent gas you can get out of the combustion chamber, the more fresh A/F you can get in, so yea, Id do the exhaust port if you have the heads off. It would have to be worth a few HP.

87silverbullet

iTrader: (11)

Have you ran it thru the 1/4? How much rwhp. What does your set up including your car consist of?

fast89stang

iTrader: (2)

When i ran it thru the 1/4 mile the carb was way off. The 1/8 time then was 6.59 and 1/4 was 10.37@129. I feel it will go 9s now easily. The pass I went 6.34 i lost 3 mph, so it should have easily been a 6.31 and i still broke out. The car weighs in at 2965, 4.10 gears, turbo 350 with 5500 8 inch converter. Vic jr with 950 ultra hp(still working on carb). Stock 07 LY6 shortblock with L92s milled .020 and pistons notched for my FTI custom ground cam. I am swapping to some 4.30s for spring and considering porting my exhaust side and hoping to run 6 teens in the 1/8 I know for a fact it should get close to teens with just gear. But I feel like the heads are performing pretty well on a small bore motor. If cathedrals would perform better, hell I need to swap I guess. I was thinking about going .010 thinner on head gasket to bump compression a tad more, but have heard mixed reviews on that. The plan was :porting the ehxhaust side some, taper down the valve guides on both intake and exh, clean the ports out some, not much at all on intake. Possible bump in compression, 4.30 gear, looking into the super vic. Just not sure on that yet. I am planning on pulling stock seats and installing racing seats from what I seen, it should lose 68 lbs there, so I feel like teens isnt much to ask, even without intake and thinner head gaskets.

fast89stang

iTrader: (2)

would you taper the guides even on the intake, or leave them alone?

Rob Carlson

i have scoggin dickey CNC'd LS3's.they're bad ***

speedtigger

iTrader: (16)

I see a lot of people say to port only the exhaust side on square port heads. The idea is get a more "ideal" intake to exhaust flow ratio. I get it. But, let me throw this question out there. Do you really think that your square port headed motor will make more power with just the exhaust side ported than it would if you ported both sides? I think not. If you are going to go to the effort and spend the money to port a set of heads, you might as well get all of the power possible.

Also, consider that max lift flow is just one aspect. Low and mid-lift flow numbers are arguable more important. Make sure you compare those improvements too when you are considering the value of porting the intake side.

fast89stang

iTrader: (2)

You make sense speedtigger.