sti410

I am using an L33 in a swap in front of a relatively weak transmission. I would like to limit torque to 650 ft*lbs but still make 1000hp, so I am looking for a cam and that will flow well out to 8k+ in a turbo application. Can this be done with stock 799 heads and an LS4 intake manifold? I am going to start with stock internals, so ideally the cam will work with OEM flat top pistons without valve interference.

old motorhead

iTrader: (10)

You probably need to upgrade your transmission. Don't believe 1000/650 is doable. You could limit boost until you get a beefier transmission, but that would limit both hp and tq.

G Atsma

Horsepower is a calculation of torque vs RPM.
Lower the torque, HP goes down, unless you rev it a lot higher.
No cam will cut torque and keep the same HP.

Darth_V8r

iTrader: (4)

What you're asking is mathematically possible, but is going to require a better cam expert than you will find on here, unless PatG decides to chime in, in which case, he's on here. If you peak AT 8000 rpm, your torque would need to be 656. I'm sure you already did some of this math prior to posting. A lot is going to depend not on the cam, but rather on how your turbo(s) is(are) setup. And valvetrain stability. That'll be the real key. you'll need more focus on the valvetrain stability than the cam specs themselves.

You'll need one helluva valvetrain set up. I highly recommend solids, top shelf springs, and top shelf rockers. my recommendation assuming a solid cam would be along the lines of 238/256-116-2 (that's minus two, i.e. retarded cam). That cam will support the RPM and should not build too much torque. Back of the napkin math, and I know there are pros out there who will either do a better job in general or outright laugh at that spec.

The rest will depend on how well your turbo(s) spool, etc.

Personally, i think it will be easier to get a beefier transmission, but to each their own.

sti410

Cool, ok thanks. What is generally the rpm limit for a hydraulic lifter setup? The tranny is very expensive to upgrade so I am hoping to work around it.

Darth_V8r

iTrader: (4)

You can take hydraulics quite fast given the right lifters. Johnson 2126ST for example, I would not hesitate to take to 8k. valvetrain stability is still the biggest issue. The higher rpm goes, the more critical it gets.

But getting to the other parts -- LS4 intake stinks. stock 799 heads, i mean, at least do a premim vlave job. And you'll need premium valves to spin that fast. And then there's all the nuance details of building to spin 8K on a regular basis. My point is that I do recognize how expensive a transmission build is. But you might be surprised after pricing everything out, it's cheaper than setting yourself up for 8000 rpm. You take those johnson lifters, custom pushrods, high end rockers, high end springs, valve job to go with that. You'd be amazed where you are after pricing that out.

Do what you want. I'm just trying to make sure you know how deep the rabbithole goes...

00pooterSS

iTrader: (40)

What about limiting boost below 5500 or so? Is there a boost contoller that will ramp in boost with rpm? Or put a turbo on it so damn big it wont spool under 6k lol

Or maybe a procharger.. they're so linear they bring in power soft ish