Have you tried different props to bring the rpm down? It seems to me with that engine youd be better served in the 54-5600rpm range. The lower cubes throw me though so I;m not sure.

If the race is long enough, the SM's will win every time, because they won't eat the motor............

i run stainless marineheaders for over 20year and love them i am now got them on a 540dart with 718hp

I've tried a labbed 25, and a 23 Mirage Plus but so far the 21 has been the best. The reason why I can spin 6000 is becuase of the 3.76 stroke. Plus I have a strong valvetrain, oil system, ect. The engine is quite happy there. I think I'm going to have the 23 repitched to 22 and lab it. This should put me right where I want to be. But if there is some thing I can do to squeeze a few more hp out of it with out breaking the bank I'm all for it. Thats why I'm curious about a single plane and/or a supersucker. Once I really get the engine dialed I'll start tweaking the prop.

I spend a lot of time with Bob M designing this engine and this is where he said to prop it.... If there is one guy who's advice I take as gold it Bob's.

It sounds like you are on the right track and I agree about Bob and his knowledge. I think bob would agree your combo, at that rpm, would benefit from properly speced full length headers. The SM are great for sure but if you are looking to squeze out the last bit at the top in a n/a app, you need good exhaust that will pull the flow through the engine. Your induction sounds good to me as is, so that leaves exhaust.

BT

Mine is basically a 525SC clone. It is a 365HP Mag with roller rockers, Inconnel exhaust & SS intake, MSD ignition, a teflon tipped 177 pulling 5lbs of boost at 6,000' elevation lakes. I would guess it is a 470PSHP motor.

Sounds like a nice combo.

Change that 365hp cam and you will have a 570hp combo

To a general blower cam or do you recommend a specific make and model?

call bob mandera! don't waste your money on an off the shelf cam.