Ryan00TJ

Currently building a new 355 over the winter. I've got everything together and have decided to retrofit to a Hyd Roller setup.

Specs
.30 over 4 bolt 355ci Decked 0.020
Eagle 4340 Crank, Forged I Beams w ARP RBs, Forged Speedpro L2304 2.4cc Dome, Comp retrofit roller lifters, Portmatched Victor Jr, Holley 4150 750 dbl pumper, Lunati Forged 1.52 RRs, Glenwood HP manifolds, 4" smooth FastGlass short risers thru hull, full MSD ignition, AFR 190cc aluminum heads milled to 70cc


Heads have 2.02 @ 1.60 valves and flow

.200 144 115
.300 208 146
.400 244 176
.500 262 190
.550 262 193
.600 261 197

With all the specs it comes out to 10.40-1 SCR with a 0.039 gasket, quench will be 0.044 with the block decked 0.020 and 0.039 gasket. I'm contemplating a custom Cometic of 0.034 to get a .039 quench?

I'm just not sure of the cam choice. I've got some great deals on off the shelf cams but wondering if a custom grind would be better suited.
The AFR's have a wonderful I/E ratio and flow great for a NA SBC.

My questions are as follows, which off the shelf cams would be better suited for my application? Am I missing anything? If anyone has any experience with grinds that would work better i'm all ears.

Comp XM276HR 224/230 .503/.510 112LSA 112ICL IVO 0, IVC 44, EVO 47,
EVC 3, 276/282 IVO 26, IVC 70, EVO 73, EVC 29, Overlap 55*, 3*

Above cam will give a 7.958-1 DCR with my setup.

Isky 225/234 .510/.530 112LSA 112ICL IVO .5, IVC 44.5, EVO 49, EVC 5,
272/282 IVO 24, IVC 68, EVO 73, EVC 29, Overlap 53*, 5.5*

Above cam will give a 8.094-1 DCR with my setup.

I've called and talked to techs at both Comp and Isky and both feel that these would be best for my setup. Idle quality is a concern with a beefed up Alpha but the techs assured me they would both idle smooth @ 750-800rpms with a 600-700 in gear idle. My previous flat tappet cam had 54* overlap and would idle fine 750-800rpms so these new HR's should be about the same.

With aluminum heads and these DCR's I should be fine for pump gas even with 10.40-1 SCR from what I understand. I've ran 10.0-1 with the same heads before with no problems.

My previous 360ci SBC around 400HP would spin a 23P cleaver 5500-5600rpms @ 69-70 GPS. I figure the same prop on a more powerful motor will spin a tad under 6000rpms. Plugging in all the numbers on DD2000 shows 440hp, 450tq with hp manifold exhaust and 475hp, 480tq with small header and muffler exhaust. The latter seems a tad high.

Thanks guys for all the help!

Previous SBC


Pulling SBC


New Shortblock


"The Big Bopper"

KAAMA

Rmbuilder/Bob Madara of Marine Kinetics is very good for advice on cam selection and has helped many guys on here with their applications.