My friend Jamie wanted a good track package and a strong highway roller with good street manners. I think we nailed it. Car pulls extremely hard to 7,400. Jamie's car was bone stock when he brought it to me.

Mods:
My ported LS7 heads 275cc runner
My custom cam 247/255
My ported MSD
NW 102
Vararam
7.750" PR's
Comp trunion
New lifters
.040" Cometics
60lb Injectors
ARH 2" headers no cats
Z06 Muffler Mod
ATI U/D
160* Thermo
Catch can
My Tune

 

Those Numbers are bling... how would you feel about that cam in a 418 with 255cc ls3 heads?

 

Impressive !

What's his static compression ratio?

KW

 

I ran it in my cathedral 416 years back retarded 2* and it made 575/530rw. I have a 416 with a slightly smaller cam and my ported LS3 top end going together in a couple weeks. Should be up in a month depending on when the machine shop is done with my block. I designed the cam to crack 600rw in all three platforms with a 416 or larger motor. I would play with where you degree it in depending on what heads you go with and how strong the exhaust port is. I am assuming you are going with TFS LS3's.

 

Thank you. 12.13 SCR 8.79 DCR 22* total timing.

 

Head flow numbers. 275cc runner 1/2" radius inlet, 1 7/8"x4" exhaust pipe. SF600

.............INT......EXH
.300......257.....195
.400......320.....245
.500......364.....266
.600......390.....272
.650......400.....281

 

Impressive numbers and it pulls over 600 for 1500 RPMs. Must pull like crazy.

 

Buddy said it pulls crazy hard. Scariest ride he has ever driven. I never got to get on it honestly. Pulled it off the dyno and handed him the keys. I had to pull another car on immediately.

 

Nice!

Regarding DCR, in your opinion, what seems to be the sweet-point for the LS engines?

Is it right in that 8.5:1 to 9:1 range?

KW

 

I always shoot for a minimum of 8.7 but never go over 8.8. I have heard of guys running 9 with certain cams and combo's. I will keep 8.8 as a max for me. I also only run a certain type of 93 octane gas. It has tested out to be the most regulated and the highest octane according to a couple different people. I have had buddies tell me that when they switch to different companies fuel they can tell the difference. I personally can't but maybe I am just a creature of habit and my butt dyno isn't sensitive enough.

 

The heads are prc250 ls3 6 bolt.
I got them a very long time ago from a friend.. u think i should ditch em for the 235??.

 

I am sure you are fine with your PRC's

 

Thanks.

I'd 'guesstimated' this might be the case.....but I haven't been in the LS game long enough to established this first hand.

KW

 

Very nice. Great attention to detail on this build. Glad to see you went with the 2" headers. In this application, I think they are worth a lot over 1 7/8" headers.

 

Thanks, I think I am going to pull it back down and freshen up the short block. There were some things I saw in there that I didn't like. Hopefully we will make a bit more on a fresh short.

I am still on the fence about the 1 7/8" vs. 2". I have an almost identical build that should be done this weekend with 1 7/8". We will see what happens.

 

I've just seen a lot of setups like this one where guys are running 1 3/4" headers. The difference, on this setup, between 1 7/8" and 2" headers, in my opinion, is probably 10 to 12 rwhp. The reason I say that is your ported LS7 heads are bad to the bone and flow extremely well, especially in the .600+ lift. My philosophy is the better the heads, the more you need the bigger headers to help remove all that air.

 

Got it, thanks. The set I am doing right now have already surpassed the set on this car. I am curious to see what they will do at 28". I reworked the short turn a bit and did some roof work as well to slow the transition and gain some expansion without increasing cross section. Should carry well to .700 this time. I broke 390cfm on my bench which should be worth 410ish on an SF600. The entire curve increased as well. I don't think I am going to be able to improve the exhaust without hurting the .3 and .4. I am not willing to give up down low for the up high on the exhaust. When I put a header on the exhaust flow falls off hard around .600. It is not like an intake port with an intake manifold on it.

 

So you do all the porting by hand, or do you have them CNC'd and then work them over by hand? You ever done much with cathedral port heads? Sounds like you sure know what you're doing.

 

I do all my porting and head work by hand. I don't want to start a war with the CNC guys but from all the core shift I have seen in stock GM castings I can keep the runner as small and efficient as possible that way. I can hit the needed areas for a given shift pattern. I fully believe you have to over port with CNC to make the masses happy by producing a "pretty" head. I have also seen a ton of really bad valve seat to valve stem shift and axis irregularities with the stock GM castings. Cathedrals are the worst by far working up to the LS7's as the best. By hand I can usually get all the ports within 1% of each other. I have had two heads off of the same car that needed two completely different port jobs on the intake and exhaust to get them right. The exhaust is the real killer. If GM dug to deep on the back wall it is a bear of a time getting them right.

I do a bunch of Cathedral work. All of my exhausts flow the same. LS1/2/3/7. The stock 2.00" valve 243/799 heads I do come in at 225cc's and flow around 320@.600. My 2.04" valve 243/799's come in around 335@.600. I honestly haven't messed with the other (241, 806 ect) Cathedral castings enough to throw out numbers on them.

 

Very nice. I take it you spec out all of your cams as well since you know the heads and flow characteristics so good. Where are you located out of?