1fastxz

iTrader: (16)

Parts are
LSX block 4.185 bore
Eagle 4.100 stroke
Vmaxmotorsports Ls3 heads with light weight valves, double springs
Going to try out two different cams
23x/24x on a 114+2 62x lift on both sides
Or a 23x/24x on a 111+2 with more lift on the intake side
Stock ls3 rockers
Morel Link bar lifters
C5R timing chain
Fast 102R with a ported 90mm with a velocity ring
Or a 95mm with a matching velocity ring
60lb injectors
Compression is around 11:7:1

Looking to make around 720/680 maybe more with the other cam.

Ryne @ CMS

iTrader: (10)

should make great torque, but it wont make anywhere near that power with those cams, intake, and compression IMO

Brian Tooley Racing

iTrader: (13)

The right cam will get you in the 680 range, something like a 248/254 116+4 You need to close your intake valve around 55-56 abdc and open your exhaust 65-70 bbdc imo. My icl is 114 if that helps...

You need a 102 tb.

I doubt you'll ever make over 700 with ported GM LS3 heads, Fast 102 and hyd roller cam on pump gas.

1fastxz

iTrader: (16)

So your saying that it will more power with a cam on a 116+4 then 111+2?

Iv seen a few LS3 headed cars making 525-550 rwhp and one or two with 570+ with cams in the 23x-24x range. With drive train lose thats close to 700 flywheel hp.
From all i'v seen L92/LS3 heads don't like big cams?
I think this heads flow enough air to support 700 flywheel hp, but i guess I'll find out in the next few weeks....

WKMCD

iTrader: (2)

We made 656/615 with 427CI. This was definitely not a max build - more grocery getter - but it's right up there in numbers. Net 577RWHP It was also done by some very good people.

Good luck.

LIL SS

iTrader: (9)

It can be done.. A buddies C5 ZO6 is making 610rwhp through a 427ci motor, ported LS3 heads, stock Fast 102..

But, he has more cam (mid 24x/low 25x with .67x lift intake and .65x lift exhaust), Compression is around 12.5 and it's on E85 (which is pump gas)..

Is it "easy" to do.. No..

Brian Tooley Racing

iTrader: (13)

I know a guy with a LS7 427 that made 680 crank and made 620 rwhp.

It sounds like your buddies cam is closer to what it would take for sure.

I guess I should have clarified, pump gasoline 92-93 octane, with the OP's 11.7:1

E85 and 12.5:1

1fastxz

iTrader: (16)

Well guess will just have to see when it gets on the engine dyno. Think it will make close to the power I want.

I should have it together and on the dyno in two weeks.
Waiting on the crank, and rods they went out to get coated today, should be back next week
My pistons shipped out today.

Stage7

iTrader: (1)

Remember his 685hp engine dyno was with SAE correction. He was 712hp STD.

Also the motor is running 12.5:1 compression and was dyno'd with 93 and Torco. He has since had it retuned with e85 and is making 630rwhp and the motor is not pulling timing on the street. Stout car. It just ran a 10.6 @ 136mph @ Cecil a week or 2 back. His mph back it up.

To the op: It's possible to get to your #'s, but it's not easy. I believe Nelson Racing engines made 720/680 STD on their 460 build with a RHS/LS3 head and intake engine and similar compression. You should try and find out about their top end setup unless your builder has done this combo before. Best of luck to you.

1fastxz

iTrader: (16)

Thanks man
The guy thats did my top end has a lot of experience with the heads i'm going to run. I got the cam/head combo from him. So I'll see what it does.

Brian Tooley Racing

iTrader: (13)

Thanks for the clarification.

I think it was 719/662 on a "hero" pull, that was a stout build. It had Mast LS3 12 degree heads with a 2.20" intake valve that flowed 380. In similar testing the ported GM LS3 heads were down 30 hp to those heads. Remember, the GM LS3 is still at 15 degree valve angle and unfavorable valve to bore position in comparison to the Mast heads.

Here is the cam info:
Notice how he said this cam is "small"...his intake valve close is 54 abdc and his exhaust valve open is 69 bbdc...that sounds familiar, you can close your intake valve a degree or two later because you have a smaller valve.

Do you know where your intake valve close and exhaust valve open points are?

Lastly, most of these engines are in the 1.5-1.6 horsepower per cubic inch range. His 461 would be 1.559, if your 451 made the same exact hp/ cu in, you would be at 703. I hope this helps.

1fastxz

iTrader: (16)

The heads I have flowed around that number...
What lift did they achieve that flow rate?

Tony Mamo @ AFR

iTrader: (13)

I call it mid 600's on the HP.....625 ish for torque.

At least thats what my air dyno reads.

I agree with a handful of others saying the numbers your hoping to see are a bit optimistic....on a properly calibrated dyno at least.

It will be interesting to see what she traps also but first things first.

IMO you should lower your expectations a bit so you don't leave with your head hung low....I would rather see you head into this with a more conservative number in your head and be surprised on the upside. I speak with the guys flywheel testing these LS engines all the time (both cathedral, L92, LS7 etc.) and have personally attended more than I can count on my hands and feet. Pardon my candor but your numbers aren't very realistic, especially with the size cam you selected. IMO that engine's power curve is going to start rolling over at 6-6200 RPM's and hanging its tongue out long before 7000. Even with a much bigger cam your numbers are optimistic. It takes an extremely well sorted out (and fairly aggressive package) to clear 700 ponies with a plastic fantastic long runner intake (the FAST)....trust me on that.

I for one am very curious to see what it makes and will keep an eye on this thread for sure.....have fun at the dyno!

Cheers,
Tony

1fastxz

iTrader: (16)

My head want hang to low if it doesn't hit the 700 mark, but if it does get close guess people will have to give the LS3 head a little more credit...

Tony Mamo @ AFR

iTrader: (13)

The big motor certainly has the advantage of making better use of the typical CSA that style head brings to the table (in fact that should help it carry a little better as well), but without knowing exactly how much work was invested in the heads and the final airflow figures its really hard to guess final output. One things certain....it would be very impressive if it tickled with the elusive 700 HP figure.

Do you have all the flow figures from the heads you could share?.....obviously all of this information is helpful when trying to get a better idea of where the package may land you when the smoke clears.

Thanks,
Tony

jjtoma

I'm be surprised, if Pete didn't know what he's doing with those LS3 heads.

Jim

1fastxz

iTrader: (16)

I'll have some flow numbers on the heads tomorrow or the next day
On the bore I'm going with it sould be in the 370+ on the intake and 250+on they exaust side
But I'll have some data tomorrow hopefully

Brian Tooley Racing

iTrader: (13)

Oh, Pete, that changes things a bit

1fastxz

iTrader: (16)

he's help me out on this build quite a bit...

1fastxz

iTrader: (16)

Well my stroke changed to a 4.125 today
So I'll be right under 12:1:1 on comp