Las,
RMbulder and I were discussing this issue several weeks ago and now since you have posted some of your numbers it is apparent. I understand the load situation, I grew up on a SF901 in the 80's. Since then I have had the privledge to learn a great deal from French Grimes on water break and inertia dynos.

The drop is apparent in different combos with different carbs, intake and such. When discussing this the only apparant constant is firing order. I understand what you are saying on the initial load of engine, but the dyno figures we have are from DTS, Super Flows, Land and Sea, and Stuska's.

Since the RAM effect in these engines useally takes place between 3000 and 3500 I believe it has something to do with that. These engines all have large bores and fair long arms in them, so as the weight of the incoming air column contines to pack the cylinder as the piston comes up and the valve closes, I think the intake pulse is slightly disturbed. Just spouting my theory.

Chris

Great. I look forward to seeing you there. Spread the word, everybody and anybody is welcome to attend.

What headers did he dyno with? yours or test headers?

This is intended to be a theoretical question and not a slam against Laz or anyone else as I would DAMN PROUD of those numbers...

Given that Otis was aiming for a 5200-5400 max rpm engine, would he not benefit slightly if the cam were ever so slightly smaller?

If this were a shorter stroke motor (or going into a car) I would love to turn that motor to 6k with that HP graph. I can only assume that a slightly smaller cam might make it slighly stronger and more efficient within his intended RPM range.

Is that a valid assumption?

Again, considering all of the variables, he was right on the money with his setup and NOBODY should complain with the HP that he achieved.

Peak HP at 5500 RPM seems pretty darn good to me! I would think the boat with that motor would be faster at 5400 - 5500 than 6000.

I would Like to place my Order for two .......

Why not turn them 5800-6000. I've always been told rpm's are speed. This would also allow for a smaller wheel giving more midrange. Just a thought.

The Torque and HP falls off after 5500 rpms. So I dont see why I would want to turn any higher and put more strain on my equipment. As far as mid range, with the 5 blade I have decided to run and those torque #'s, my midrange should be my strongest point

His headers . We are having some installation issues with mine as we speak. Numbers shouldnt drop off at all with what I chose. Dana Torque flows

Nice Bob .

When are you testing?

Bobby