Biggus

iTrader: (1)

Thanks for the help BT!

I'm open to suggestions on this combo. What would you recommend for carb? Any opinions on this cam?

My main goal for this project is to make a 600+ hp test bed engine that will last 400 hrs.

Thanks again,

Kurt

bobl

That engine is very close to the engine I have. I'm running the BB2+ heads with an Ultradyne cam very similar in spec. It has a Crower rotating assembly, 9.3 compression and is running a Holley style MPI system . It actually dynod at 608 HP at 5300 RPM and 648 Ft. Lb. at 4500 RPM. It really laid down past 5400 RPM with that cam. I ran it for about 250 hrs. At that point I installed it in another boat so I freshened it up. It was perfect inside except for the cam. It was beginning to scuff on the opening ramps. I replaced the cam with a Crane 741 and ran it another 150 hours. Now I've added a Whipple to it and so far have about 70 hours more on it. I'm using it as a test bed for my shop. So I can demo to people how dependable a custom engine can be. I'm going to keep running it until something fails, then see why. I'm turning it to 5600 RPM now. I don't run it very hard. Most cruising is 3500 rpm, 4000 tops. WOT blasts never last more than a couple of minutes. Hope this info helps you out.
Bob

Crazyhorse

Kurt, contact KAAMA for the specs on his current 565 engines as well as his previous 540 engines. He has exactly what you are looking for.

KAAMA

iTrader: (1)

bobl---I like your combination.



Kurt, My 540's also had about a 8.7 comp ratio, Holley 950cfm carbs, Dart single plane intakes, Dart PRO-1 310cc heads fully ported by JimV, a Crower hyd roller 236*/244* on 114* lobes, and Stellings headers. They made something like 680hp @ 5700rpm with dyno headers on Tom Earhart's dyno---torque peaked out at right around 4600-4800rpm @ about 680 foot pounds. Idle in neutral was about 800-825rpm.

As far as the carb size goes, when I first built my 540's I used some Holley HP830cfm annular discharge carbs and they gave the engines very good throttle response. When the 540's were on the dyno, we did back to back tests with the 830cfm (#86 jets all 4-corners) vs the 950cfm (#78 jets all 4-corners) carbs I now have and at 3000rpm the 950 out did the 830 by 13-hp and 22-lbs/torque and at 5250rpm the 830 out did the 950 by 6-hp and 6-lbs/torque. Other than that both carbs were about neck & neck on the numbers and too close to be of any real difference. Only at 5400rpm did the 950 really begin to show some gains over the 830, but only by 9-hp and 9-lbs/torque. At 5500rpm the 950 crowned the 830 by 16-hp and 15-lbs/torque. I probably would have been fine by sticking with the 830's. I also remember Tom Earhard saying in the 25+ years of dynoing engines that he never saw an engine on his dyno that "followed" as well as what he saw with my 540's and the combination I had with the 830cfm Holley's---so, he was pretty obviously pretty impressed. Of course now that I have the 565cid engines with the air that they require, the 950's I now have will be more useful, and better suited with them.

My friend had some 540's built when he first bought his 35' Cig. They had Dart or World Products 308cc cast iron heads that were lightly bowl ported by JimV, 850cfm carbs, 8.8 comp ratio, dual plane intakes, and the Crane hyd roller 741 cams and they made 595hp @ about 5500rpm on the dyno ( I do not know who's though). Which is very close to bobl's combination----So, it looks as if you're in the ball park Kurt.

Okay, here's my disclaimer---It sounds like you have your own goals, and priorities for what you want these engines to do as I did with mine. I personally like the idea of a lower 8.7 comp ratio that you are wanting to run and I think you are definately in the ball park with your choices in order to achieve your goal of 600hp----but hey, BEWARE, I am not an engine expert so, what do I know? I just kill bugs for a living. Anyway, have fun with your project.

Crazyhorse

It's a small price those bugs pay for the betterment of boating mankind. Keep up the research and we'll keep growing the bugs.

getreal

I have a brand new "Engine Analyzer Pro" desk top dyno for sale. I paid $499.95,now they are $459.95.

Check out there web site: http://www.auto-ware.com/software/eap/eap.htm

Make me an offer before it goes on E-Bay.