This is my first build! I have a 2000 Pontiac Trans Am and I am building a 6.0 lq4 for nitrous. I am going with forged pistons and rods, stock block, stock crank, mild to aggressive cam, fully worked 243 heads and probably max shot at 250-300. It's a street car (full weight) on a 275/60r15 radial with a th400. It will be ran quite hard and will have some 1/4 mile passes on it. What intake would you all recommend for this setup? what kind of power can i expect at the tires? any advice will be appreciated.

 

Not to start another cathedral vs rectangular debate....but...
you could go LS3 heads and intake for a lot less $$.
My SBE LQ4/LS3 topend makes 450ish to the tire with a decent cam

 

Ok thanks! whats the casting # for LS3 heads? So with a 300 shot it'd be around 750?

 

Street car I would say stay with the catherdial port heads, and would use a 102 fast with Nitrous outlet plate. I Would say 680 to 750 rwhp can be obtained.

 

Why cathedral over rectangular for a street car? Good, i already have a whole system from nitrous outlet lol. Thanks!

 

The generally produce more torque then rectangle ports. Helps keeps your heavy street moving! You can search and find a ton of info on the subject.

 

This has been debunked many times. I fell victim to this thinking and am stuck with my cathedral setup. I don't make any extra torque and I'm down an easy 30-40hp at least vs a square port.

 

lol. K.

 

Hehe

 

Hi AJ, your "243's" will work fine with some good S/S valves and good springs.
Your HP will come from the N20.
I would fit a 90mm+ Air Door Intake, a Z-06 or a LS-2.

The Camshaft is where you will make Torque/HP.

What is your guess for a camshaft ?
What Ignition Coils do you have fitted ?

Lance

 

If it is fuel injected, the FAST 102 is about as good as it gets for a stock displacement cathedral port engine in the 3000-6500 RPM range. For a 250-300 shot, I would do a direct port nitrous system if it were mine.

For a camshaft, If you are only interested in performance on nitrous, I would this Cam Motion Nitrous camshaft:
Part Number: 03-01-0082 Grind # XA238/365-XA254/355-15+5

If you want a camshaft that is a compromise between N/A performance and nitrous performance, I would use the Titan King LS1 camshaft:
http://www.cammotion.com/camshafts/t...236-244-112-3/

For headers, I would get some 1 7/8" units from American Racing Headers or the vendor of your choice.

For a TH 400 converter, I would check out PTC.

Power wise, depending on the heads and intake your choose, it should make between 450 to 475 through an unlocked high stall depending on all the variables.