ONESICKGLADIATOR

well said


Rick OSG

44MTI

My engine builder just built a set of 557's with the new 18* dart and he was very impressed. They made the same hp as freedom 1's 572's with big chisf's, also built by the builder. Since I'm in the market for new heads, what is the advantage of these over big chiefs.I think my engine guy said I could use my old pistons but rockers were different, hard to find intake to match and exhaust flang is rotated.Help I'm so confused.

Mr Gadgets

42MTI,
What kind of power did those 557" motors make anyway. I would like to know about the build up on those. Crank, Rods, Cam, Block, etc. Sounds very interesting. When I talked to Dart about the 18* heads they implied I would need more cubic inches to do them justice.
I also talked to them about the Big Chiefs and they said that you would need to go over .800" lift to make them work and that is not a reliable setup in a boat..
If someone wanted to buy my heads and Hogan sheet metal intake, I would have a set of the 18*'s ordered in a heart beat..

Thanks
Dick

GPM

42 MTI, what size motor are you talking about, blown or N/A.

44MTI

These weren't my motors so I don't have all the details, but here is what I do know
Freedom 1=572 cu
solid roller
14-71 BDS intercooled
Big chief heads
62-6400 rpm=1228hp and over 1000tq. from 3500-6000+rpm

Next motor 557 cu
solid roller
blown and intercooled
Dart conventional style heads with 18* valves
just over 1200 hp.

sorry I don't know more about them, I will find out as I go through my rebuild.Oh they both ran c-12 for fuel. Just for comparison here are my motors
598 cu
callies crank
crower rods
brodic 2x heads no port work no even port matched
solid roller 663/638 lift, 298/308 duration
14-71 Blowershop,lee intercooler
1050 (2) dominators
8.5 compression 9# boost
91 oct.=1030 hp,1000 tq.

Next, quad rotors, new cam, new heads,brand??????? still researching probably brodix 2 extra CNC, Hopefully 1200 on pump fuel?????

KAAMA

With the new Dart 18* heads I have heard that other bolt-on components such as headers, intake manifolds, etc, need to be changed/modified/altered in order to make the Dart 18* heads work. Does anyone know if there is any truth to this?

GPM

I like the 598, I put one together with BB 2 extra cnc port, 9.0 compression, .748
solid roller, procharger 15lbs of boost 94 pump gas with booster, it dynoed at 1372hp @ 6200, 1198lbs torque @ 5900, it was over 1100 from 4400 thru 6500.
I tried a set of Big Dukes lost some bottom end but picked up 6 miles an hour.
To run the Big Dukes I had to change, pistons, rods, pushrods, T&D rockers,valve
covers, the exhaust port is raised an additional 5/8 inch, header port is bigger, intake manifold. You might want to look at BB 2 extra cnc or AFR 357 magnum.

GPM

The Dart 18 is a symmetrical head, it uses the Big Chief, Big Duke style parts, cost
me around ten grand to make the change.

GPM

You might want to check out, WWW.M2RACE.com

44MTI

Yea I'm thinking the 2extra cnc is probably me.Don't need to spend the extra dough for big chief and all new part to go with them

I just talked to dart today and they said with the 18* conventional heads you would need new pistons,shaft rocker assembly,and intake, at least.also the exhaust flange side of the head is angled to bring the header closer to the blower, so you would need a special adapter plate. This is also what my engine said they had to do with their motors.
Sounds like all the expense associated with big chief heads to me, $13000 was my bid just to change to big chief.Think I will stay with CNC convention 26* heads.