MILD THUNDER

iTrader: (3)

Icdedpenis's engines made close to 900hp at 6200 if i recall. At 5500, they were making 840ish hp.

The merlin heads will probably be your biggest restriction. Did you have the heads flowed ?

I really wouldnt be worried about "blowing raw fuel out the exhaust", or losing sleep over the 741 vs 771 cam. If those heads flow like i think they do, im betting youd prob be better off with something like a 651 244/256 cam, to help make up for the head flow. If i recall the IE ratio on those heads is pretty poor out of the box, and would prob really like a cam that has a large split in duration like the 651 cam. The 651 cam, might not be the best choice when using a head that has an excellent IE ratio, and low boost.

With that being said, any of those cams listed in this thread, will work, and probably make enough power for you to chit your pants in that hull.

mike tkach

iTrader: (3)

i agree that the extra exhaust duration will help a head with poor exhaust flow but it worked with my dart 320,s as well.i believe the exhaust manifold or header is an extension of the exhaust port and can also restrict flow.

C1000

It's hard for me to absorb that Comp would suggest a cam like that for a 540 N/A let alone a blown application!! dosen't pass the smell test if you know What I'm thinking.........

Black Baja

iTrader: (2)

Who at Comp gave you this recommendation?

powermizer

Thanks for the advice from all. his name is Jeffrey Peritore. I guess my biggest concern is having such a low cruise rpm. I have to believe that at such a low rpm 2200-2500 the events are happening so slow that a boosted engine would blow some gas mixture out the exhaust with the bigger cams with more overlap. Thanks again for the help.

articfriends

iTrader: (1)

Mild thunder is correct, out of the box merlin heads have a very weak exhaust port, ported, thats a different story, I struggled to make 700 hp years ago with untouched ones on a blown 540, fwiw.

powermizer

I have not had them flowed. there is some pocket work done on them. As I said I wasn't looking for every MPH out of this thing, but if I could go with a little less overlap using a better flowing head I would be up for doing it. one concern that I have is that the boat holds 60 gals of gas, and we want to take it to Lake Powell, so I am trying to get half way decent MPG. I know it sounds silly. I crack myself up just thinking about it. A guy builds a 540 with a blower and wants good fuel mileage. lol

powermizer

I was looking at the Dart pro 1 heads. It looks like TFS heads in the same size, out of the box made the same power. Decent price on the TFS. I only use the boat in fresh water, but still worry about corrosion. maybe the pro one coated heads are better?

MILD THUNDER

iTrader: (3)

My head guy, really likes trick flows heads. Quality , cost ,performance.

My little 468ci engines with 420 B&M blowers, have crower 236/245 114 LSA hyd roller cams. Installed on a 110icl, the intake valve closes at 48*. This past winter, i retarded the cams 4*. Intake valve obviously now closing later.

The static comp is 8:1. The cylinder heads, measured out at 330cc after some throat cut and blend. Twin 850 carbs.

Textbook says these engines should be turds down low.

At loto, night time speed limit is 30mph. I had no issues running on plane at 2700-2800rpm. When cruising along at 3500rpm. And if the drives are nuetral trim or higher, and i stab the throttles, i blow the 17" cleaver props out, and hit the rev limiter.

powermizer

What do you limit your RPM up top?