More Power

[Blue Streak 21]

So it didn't take long, I want MORE POWER!!! The car is a lot of fun at the track, but it lacks the torque I'm used to from the Z06. With slicks on the car I don't have to modulate throttle coming out of most corners. The accelerator petal has become a on/off switch. The 5.0 l motor just runs our of umph after 5000 RPMs. I'd like it to run strong to 6000, making more hp all the way. It doesn't help that I'm at 5000 feet of altitude. Lack of ambient pressure (12 psi vs 14.7 psi) robs the car of serious power. Seat of the pants feel says that I'm not seeing 200 hp at the rear wheels.
I've started the power program by buying a larger throttle body (75 mm), and new intake manifold (Typhoon). They are sitting on my work bench ready to be installed on the car. I'm also thinking about aluminum heads, and maybe a bumpier cam. I think I've read that the motors are good for about 320 hp (corrected) with these mods.
My questions are:
1) Which heads would you suggest? Edlebrock RPM, AFR, Patriot, etc.???
2) What spec cam shaft?
3) If I get the big valve heads do I have to increase the size of the notches in the pistons? By big valves I mean intake valves at 2.02" diameter vs. 1.90" diameter.
4) What other factors am I overlooking?
Thanks for your input.

[panoz302]

Jerry,

A friend just did this to his gtra, he did Holley intake, edelbrock heads, and came no tb, I do not think he went with the oversized valves. I do not know his exact specs. A local stang shop did the work. But they def. did a bumpier came, and raised his RPM to up close to 7k. I think he picked up 90 hp at the crank and 65-70 at the wheels. But the rpm and higher breathing is a big plus.

[Blue Streak 21]

Thanks for the reply. Soulnd like he's making the kinda HP numbers that I'd like to attain.
From what I can tell the Edlebrock RMP heads with 1.90" diameter intake valves are the way to go. No additional notching on the pistons are required with those heads. AFR heads are a bunch more $$$. I guess AFR heads are the best on the market right now.
I'm going to use a 75mm TB and same size mass air meter. I gather when you change out the mass air meter you need to get one that is calibrated for the correct fuel injectors. I guess the car has stock 19# injectors currently. That combination should really free up the intake side of the motor. Probably a bit of overkill with a 75mm system, but if I want to go bigger on the cubies in the motor (like a 347 stroker), I should be in good shape.

[panoz302]

Good luck, my buddy had issues with his bottom end after the intake,cam,head change over and went ahead and did a total rebuild after that. I think the best bet is to inspect the crank and journals if you are going to increase the hp. It seem some of these motors have a bit of abuse on them, which is expected. The rpm limiter has help keep them in tact, but it is apparent the motros with 500-800 track hours is still an amazing thing in itself. I think I would do the trear down and the stroker kit at the same time, then you know what what you got.

[Blue Streak 21]

Originally Posted by panoz302

Good luck, my buddy had issues with his bottom end after the intake,cam,head change over and went ahead and did a total rebuild after that. I think the best bet is to inspect the crank and journals if you are going to increase the hp. It seem some of these motors have a bit of abuse on them, which is expected. The rpm limiter has help keep them in tact, but it is apparent the motros with 500-800 track hours is still an amazing thing in itself. I think I would do the trear down and the stroker kit at the same time, then you know what what you got.

My motor has 50 hours on it, so I'm hopeful that it can take the additional stress of 320 HP.
I agree a 347 is the ideal motor with this block. I guess 400 HP is obtainable with this combination. A that would be a nice amount of power to have. I guess there is always something more you can do to the motor.