sydneyACE

Thanks again for all the help!

I've been hitting the forums hard doing my research.
I'm leaning towards LS3 heads now for sure. They have bigger valves and the intakes are hollow like the LS6's. After-all the whole-idea of using a larger bore is for better breathing. (And to increase displacement without a long stroke.)

I was thinking something like this for a cam:
228/238 .575/.590 116*LSA

The lift isn't super-high, the duration is long-ish so the acceleration rate on the cam shouldn't be very high. If I used a high-quality beehive valvespring, something like the PAC 1219s or 1519s, that should help keep the weight down. (Plus with the beehives I could run light-weight titanium retainers.)

Lifters seem to be very hit and miss. Obviously linked lifters would seem like the way to go, but I've seen quite a few threads where people have had issues with them failing.
The GM Performance 88958689 (also known as the "Caddy" lifters) seem to be a viable choise as well. Apparently they were designed specifically for high-rpm applications for GM's racing teams. CTSV-R, C6R, etc. I have seen several reports of those failing as-well. It seems maybe guys were using them with too-high of a lift cam? I dunno.

As for rockers, somebody mentioned something about modified stock ones? Anyone know anything about that? The thing I've noticed is that the "trick" roller-tipped ones are heavier, and also have a larger moment than the stock ones. The general concensus is that roller-tips aren't really necesary unless you have a high lift cam because of valve tip scrubbing.

Anyway, my post is gettin long-winded.
Thoughts?

gnx7

iTrader: (28)

If you want to road race it hard and make it reliable with a budget.... also keeping it cool at the same time.... then use the keep it simple stupid method instead.

You want big cubes and keep the RPM's under 7K and you won't have issues. Good luck trying to keep a forced induction V8 cool on a road course going all out for 20-30 mins at a time. It will heat soak.

LS3 heads make waaaaay more power than a production cathedral port head. LS3 head flows 330cfm stock. LS1/LS2 head is more like 260cfm.

budget combo:
LS3 block, 4.1" crank, forged rods/pistons = 427ci
LS3 heads/intake or TFS 235's and FAST 102 if you have the $$$
Accusump bandaid or real ARE dry sump oiling system and an big oil cooler
Run as much compression as your fuel octane allows
Should achieve 550+rwhp with a good set of heads and have total reliability.
If you want to spin above 7K safely and repeatedly I would recommend Morel link-bar lifters. They are $550 vs. $120 for the LS7's.

650rwhp+ is going to need the transmission weaknesses addressed (upgrade to a TR6060 and stronger rear '06+ Z06 diff) This drivetrain mod alone is an easy $6-7K in parts getting good deals and doing the work yourself. A C5 transaxle won't handle the abuse over time.

As they say.... you gotta pay to play.

sydneyACE

gnx7:
I appreciate that you're trying to help.
I don't know if you read my original post, or any of them thereafter.

You need to read them.

I have already decided that the LS3 heads would be the best option.
I do NOT want big cubes.
I only track it 1-2 times a year.
This is my daily driver, not a race car.
I don't want a big cube, NA, track car.
I want a small cube, FI, daily-driven, street car that can survive at the track.

I will deal with the heat soak issues as they come-up.
I have already talked with a bunch of FI guys who track thier cars.
Meth helps a lot.
Also,
With a PD blower, you typically use a Air/Water/Air heat-exchanger (intercooler). I'm not sure if it will work or not, but I think by using an oversized pump and running the coolant through one of those fuel-cooling cans filled with ice, I should be able to keep the IATs down.
If that doesn't work, there's always E85.

Anyway, that's not really what this thread's about. I'm here trying to figure-out which components I need to use to make the valvetrain safe.


So-far this is what I've come-up with:

Keep the ramp-rate (accelleration) of the cam low.

The body of the factory rockers are fine, but the trunions need to be upgraded. I haven't found any evidence of a factory rocker with the trunion-uprade failing.

Valvesprings need to be upgraded to quality units. I'm thinking the PAC 1219s or 1519s would work really well for my goals.

Some good pushrods.

Lastly there's the lifters, Jury's still out there. I think the "Caddy" lifters are a great solution if you don't run high-lift (over .600 or so).

Anyway, like I said. I appreciate that you're trying to help, but I think you missed the point of my build idea.

1lejohn

iTrader: (9)

With the size of the LS3 valves you will want double springs like the Pacs 1121, 1521's. The bee hives won't cut it at the level you want to run. I've already been though this with my build. The stock rockers with the comp truion or Harland Sharp upgrade will be fine at the lifts you are talking about.

I'm not sure using the stock 3 valves in a FI app. I went with the REV inconel on the ex. and their lite weight intake's. Stay away from Ti it gets expensive.

Good luck with your build.

Orr89rocz

iTrader: (13)

I dont think you'd want big solid LS3 valves for 650whp application trying to rev to 7500. You probably can control it in a hyd roller application but wont be as easy as a smaller lighter valve setup. I agree with the above that you want a good double spring. PAC's will work depending on the install height they have several different kinds. Their circle track 1300 series springs are good from what I hear. I have them on my new motor but havent run them yet.

I think you could do this on a smaller valve (lighter) cathedral head setup with enough boost. With boost you need abit more spring pressure than you'd use with n/a to the same rpm.

I agree on the link bar lifters. Morels are top notch stuff.

Lighter valve will be easier to control. Titanium retainers and those pac double springs will handle hyd roller to 7500 no problem.

My buddy has spun a 4.8 to 7500 peak hp with a turbo setup using stock LS7 lifters and a stiff double spring. Wouldnt use it for sustained runs at 7500+ but it was controllable.

The cam lobe will need to be designed around your rpm range. Too aggressive of a lobe and it will eat valvetrain and may not be stable.

Gregory

iTrader: (4)

sydneyACE: I sent you a PM about shaft rocker arms. I have used the GM "Caddie" race lifters (P/N 88958689) to 7k, and driven them thousands of miles without issues.