headers&managing rpm

[sothpaw]

Everyone,

I wonder if adding headers makes the rpm at which you get
your horsepower peak decrease?

I have read that performance cams work by moving horsepower
up the rpm curve, so that peak hp occurs later (higher).

If I add ported/polished heads to the car, I think peak hp will
occur may be a little later--5500 instead of 5200 rpm.

 

[Vettelt193]

headers should be an all around increase, (but may kill a bit of low end torque) But, you will really notice header's increase in power at high rpm, so it may further increase your peak power RPM.

 

[BiZ]

Headers moved my peak power from 5400 RPM to 5800RPM. But I was making more power at 5400 RPM w/headers than without.

 

[sothpaw]

any way to decrease?

I'm worried that when I mod the car, if I go the cyl. heads/52 TB
route, the horsepower peak will be too high for the car to maintain
durability.

Vettelt193 mentioned something months ago that LT4s have a diff.
crank and so the bottom end of the engine is built to withstand
that higher rpm. I have no intention of rebuilding the bottom end
of the engine, so I would shift at 5900 (stock rev limiter was 5850--
hopefully GM built the bottom end to withstand 5900) and so I want
peak horsepower at maybe 5500 or 5600 tops.

As the peak is now 5200, maybe just the cyl.heads/TB will be ok.

Vettelt193, thanks for bringing up this issue before--exactly the kind
of thing I want to know before I do some mods.

 

[BiZ]

Change the intake to a SuperRam. That should keep the power where you want it. And increase low end torque. The LT1 manifold is very similar to the MiniRam. Which is for making power at higher RPM. Someone has to have done a SR on an LT1 somewhere.