iroczman380

OkOK i have the vortec heads, 1.94 1.6 valves, decked, and bowl cut.

I have a 383 stroker motor, with a comp cams 268h with 218/218 duration@ .50 with 484/484 lift, with 1.6 rollers, and 110 lobe seperation.

I dont know which way to go

should i put a holley 750 on, or use the vortec tpi setup!!!

Which setup will make more power across the powerband with the cam and heads that i have.

I know it might make a bit more torque with tpi, but id say a 383 already has plenty.

I want at least 350-400 rw horsepower and be able to run low 12's, and maybe 11's with some spray.

Everything is ready to go the heads are bolted on with the roller rockers, all i need to do is get the induction setup. Which way should i go???

I know this is a carb board but i want the pros and cons of both, i want to know if the carb will really make that much more power.

and what else do i need to achieve 12's and maybe 11's, see sig, thats all
l

RB83L69

That's an awful FI cam, and not the best carb cam any more either.

If your heart is set on using it, go with a carb. If you would prefer FI, get a cam that's more appropriate to FI. With a set of stock Vortec heads, the TPI system won't cost much HP compared to a carb, maybe as little as 6-8%.

I doubt you'll get more than 350 RWHP out of that motor regardless of induction system.

Damon

I agree that cam won't work well with a long-runner TPI setup- the lobe separation angle is a bit too tight (110*) for a TPI.

It will work great, however, with a carb and a cheap dual-plane aluminum aftermarket intake (See Edlebrock for an intake that'll bolt right onto the Vortec heads). I have personally used that cam several times on mild street performance engines and it's still a good choice, in my opinion. It's not as aggressive as a "Magnum" or "Extreme Energy" cam but your valvetrain will thank you for the less aggressive ramps on it- especially since you're going to a higher 1.6 ratio rocker. Valvesprings and other valvetrain components will last nearly forever even if the car is driven daily as a commuter car. More aggressive cams tend to beat up the valvetrain more and wear out valvetrain stuff more quickly.

Make sure your Vortec heads are actually capable of handling .484" lift at the valve. I (and others) will tell you that in dead-stock configuration you're going to be marginal for retainer/guide clearance at .470" lift. Also, the stock springs that come in Vortec heads are just that- stock. They won't control that cam over 5000 RPMs, especially with the higher ratio (1.6) rockers. ALWAYS install the springs that are recommended for the cam. Fortunately, the springs recommended for the 268HE cam will drop right into the stock Vortec spring pockets, no machining required. Just make sure your heads can handle .484 lift. When you swap springs that's the PERFECT time to deal with any minor machining that may be required to prevent slamming the retainer into the valve guide (and valve seal!) at maximum lift.

Don't get me wrong- compared to a stock cam it's still much more agressive in every way, but not "bleeding edge". You should be able to make a REAL 325-350 flywheel HP with that combo if it's tuned well. Sound disappointing? It won't be. Remember that a new LS-1 probably only makes about the same HP at the flywheel and you know how fast they go.

You got a good combo going there- nothing you should feel upset or embarassed about by a long shot. Just pay close attention to the valvesprings and clearance issues at maximum cam lift with your chosen rocker arms and you will build a strong running engine that lasts a long time.