dckrafft

I am tired of adjusting valves on my solid roller cam and want to switch to a hydraulic roller. The engine specifications are as follows:

GM Gen V block 4.50 bore
GM crank (stock steel)
Childs & Albert "H" beam rods 4.250 length
JE pistons (10.4 to compression ratio)
Dart 320 heads with 2.25 intake and 1.90 exhaust valves
Crane roller rockers
World products single plane intake manifold
Holley 830 cfm carb.
MSD ignition and distributor (6M)

The engine currently has Gill "offshore" manifolds with wet tail pipes. The boat uses a Bravo drive.

Any suggestions as to what cam to use would be appreciated.
Thanks,
David

KAAMA

iTrader: (1)

David, I would suggest calling "rmbuilder" (Bob Madera) of Marine Kinetics in N.Y. His number is: 585-654-8583 He has been a great help in engineering cam profiles for many boaters on here, and abroad.

HARDCORE A/O

I take it that the Con Rods are .25" longer than stock (i.e. 6.385" )- not 4.25".
Sounds like a pretty good combination to me.
I'm not a "Camshaft Guru" but I would think that you would need the following specs:
Intake duration @ 0.050" between 228 - 238 degrees
Exhaust duration @ 0.050" between 230 - 244 degrees,
Lift (w 1.7 rockers) .575" - .625" Intake & .600" - .640" Exhaust.
Lobe Separation Angle: 112- 114 degrees.
I think in a N/A application you should install the cam 2 - 4 degrees advanced. It should make better average power and idle better that way.
If memory serves, my Teague/ World Products 509 came with a Crane cam that had .587' lift Int. and .610" Exh. and 228 and 234 degrees @.050" Intake and Exhaust duration. This cam has 112 degrees lobe separation and to the best of my knowledge is available directly off the shelf from Crane.
The Teague motor supposedly made 574 HP and 634 ft. lbs of torque according to the dyno sheet that came with the motor.
If you had a "dry" exhaust I'm certain your motor would make more power with a larger cam but it might be too risky beecause of the potential for reversion to try anything larger with the Gil exhaust.
However, I have Lightning Headers (wet) on my boat and I'm currently running a 244/254 .650"/646" Lift 114 deg LSA Comp custom grind in my 509 and I haven't seen any signs of reversion, but I try to keep the idle up above 800 RPM (in Gear) to reduce reversion.
Hope this somehow helps.

dckrafft

Thanks for the information.