articfriends

I made hp in the mid 600 range on my 540 dynoing it on Crocketts dyno (with no accesories but it did have cmi headers on it) using a extremely ported/machined 502 mpi intake and bored out throttle body. It too went rich at about 5500-5600 on the dyno and went rich in the boat at about 5200 plus when fine tuning the mefi on the water,Smitty

MadMat

Some of the old Kheikhafer injected race motors had spacers!

But, setting 600 as a target, It wants to be an "easy" 600, without having the motor trying to fight the inlet to get enough air.

bcarpman

You are right that it is not an elegant solution, and although it will work it is by no means optomized. The design compromises for a carb manifold are not the same as an EFI manifold.

A typical single plane carb manifold has too small a plenum volume for best power with efi, and the runners are unequal length and too short. These are compromises necessary when the manifold needs to distribute fuel as well as air.

We recently had another thread about the HP500 manifold and porting. I'm guessing that if all you're looking for is 600hp, the Hp500 manifold with a little porting is probably the best solution currently available for reasonable $$.

TylerCrockett

The Holley manifold will make good HP but you lose alot of much needed Torque getting rid of the long 500 intake runners.

MadMat

Thanks for all the answers guys.

I guess the next question is what's needed to get 600 from the bulldog. Will it need both heads & exhaust? Or can the heads be pocket ported and that will do. How much HP can you get through a GIL exhaust.

Leaving everything other than the inlet "stock", how much extra can be had, if any, from a different cam.

Cheers
M

Bob280Silencer

What about using a tunnel ram(fairly long runners) and adapting it to fit a 2000cfm throttle body?

johnlomant

I have a Paul Phaff 598 with a ported arizonza speed and marine intake on it which makes over 700hp and 730 torque. It does have a huge cam to compensate on the intake restriction. Its a sleeper when you pop the hatch and it looks like a 525.

johnlomant

Here is a picture of the motor

Bob280Silencer

johnlomant,those runners are shorter than the hp500efi manifold.It probably flows more too.At what rpm is your max tq?

johnlomant

4500