Monty

I just ordered 2 new Dart Big M 4.500" bore, 9.800" deck blocks, and 2 pair of Brodix BB-2 Plus aluminum cylinder heads. With the 119cc combustion chamber and JE forged pistons it will work out to 9.0:1 compression.

Has anyone used the Brodix BB-2 Plus heads in a marine application? Is it necessary to hard anodize the heads in a freshwater (Lake Michigan) application?

With a 234/244, .527"/.544", 112 LSA hyd. roller cam, anyone think I would have reversion issues with Stainless Marine exhaust?

DD2000 predicts this:

RPM......HP......TQ
2000....245.....643
2500....314.....660
3000....374.....654
3500....430.....645
4000....480.....630
4500....513.....598
5000....523.....549
5500....503.....481
6000....462.....404

Crazyhorse

You can contact KAAMA. as he's had extensive experience with many different 540 variations.

Monty

Sutphen30,

I got the flow numbers from the the Brodix website. I've used Dart heads in the past with good results as well, I've got Dart 18* CNC heads on my Vette's twin turbo engine. However, the machinist I use, Fast Times Motorworks, recommended the Brodix over the Darts for smaller port BBC heads.

I'm not set on the cam spacs yet, that was just one that I was using for modeling. In any case, it will still be relatively mild. I'll sacrifice a few hp in return for increased reliability and lower maintenance.

Monty

Okay, I checked out the AFR 305's and at least according to their claims, they do have better intake and exhaust flow across the lift range. I'll have them order those instead.

Do you think Copper Beryllium valve seats are a good idea?

Monty

With the Crane 741 and AFR 305's, DD2000 predicts:

RPM........HP........TQ
2000......247.......647
2500......317.......666
3000......380.......665
3500......441.......661
4000......497.......653
4500......546.......637
5000......573.......602
5500......577.......551
6000......551.......482


Is this too much for Dollar Offshore prepped TRS and Borg-Warner Velvet Drives, assuming I'm easy on the throttles out of the hole?

According to the speed calculator on go-fast.com, assuming 8500lbs, these would be good enough for 82 mph peak at 5000 rpm, and 72mph cruising at 3500 rpm.

PatriYacht

Could one of you computer guys run the same combination with Dart Pro-1 325's and Crane 651 cam on your DD. Cam specs. are 244,256 @ .050, .632/.632 lift. 114 sep. Thanks.

KAAMA

iTrader: (1)

Here's the dyno sheets from my short deck naturally aspirated 540's on Tom Earharts dyno. Holley HP950's, Dart single plane intake manifolds, Dart Pro-1 aluminum 310cc heads fully ported by JimV with 2.30" intake valves and 1.88" exhaust valves, Crower hyd roller 236*/244* on 114* lobe seps, 9.6 comp ratio, 32* timing, full length tubular dry headers, MSD billet distributors, MSD Crank Triggers with Crane Hi-6M ignition boxes.

RPM TQ HP
1500 507 145
2000 545 207
2500 539 257
3000 614 351
3500 598 399
4000 662 504
4500 692 593
5000 684 651
5250 658 658
5400 655 673
5500 651 682
5750 639 699

Tinkerer

Just got off the phone with Mark ( KAAMA )
Although the engines produce HP all the way up at 5750 RPM he doesn't run it above 5500 - 5600 MAX.
That is what JIM V. heads will get you.

Just think what these engines would produce at 10.5 to 1 compression and a more agressive cam.

And it would still run on pump gas.

PatriYacht

Those are some startling numbers from a small set of heads. I'll have to call Jim V. this winter.

bobl

Monty, I have a 555 with the BB2 Plus heads with a bowl port. It has a mild cam (232/240 at 114 LSA) and MPI. Running 9.4 compression it made a little over 600 HP on the dyno. I now have over 200 hrs. on it with nothing but oil changes. I only turn it to a max of 5400 RPM.