IRONMAN

A 226/234 with 540 lift crane would be the max size and would require roller rockers and piston clearance check also. It would make max power close to 4900-5000 unless you port the heads then it would probably run to 5200 if propped correctly. If you do not want to change the rockers than a 218/226 at .500 would be a better choice. Good luck.

Audiofn

Ok for what it is worth and I would like some input on this. Big Block Chevy Marine Performance recommended going with a Comp Cam Grind XE 256 H 10. This is Part # 11-234-3.

Duration:
212 degree intake durration
218 degree exhaust duration

Lift
.480 intake valve lift with 1.70:1 Rocker arm
.283 intake Lobe Lift at lifter
.485 Exhaust valve lift with 1.70:1 Rocker arm

Timing
110 degree intake to exhaust lobe centerline seperation
108-110 degrees after top dead center intake lobe centerline position in crankshaft degrees
110-112 degrees before top dead center exhust lobe centerline position in crankshaft debrees.

This cam will work with stock springs and retainers and valve guide seals.

There is no idication of what to expect for a performance gain.

Jon

Griff

Jayl13, I have the crane #134241 cam in my 454 Mag. It has a nice lopey idle, but still idles fine at 750rpms. It also comes in a kit under the #134242 and is only about $150 for the kit from Summit.

LOONER

THE PEOPLE AT ULTRADYNE KNOW THER SH*! ABOUT MARINE ENGINES,GIVE THEM A CALL THEY WILL GIVE YOU SOME HONEST ANSWERS AND HELP YOU SELECT THE RIGHT GRIND. GOOD LUCK!

RickR

Jayl
You cannot run Davids 226/236 112LSA cam with silent choice.

Jayl13

I have silent choice yes but is it ever engaged HELL FREAKIN NO!!!!!
but what does that have to do with anything?
now im lost?
Please explain
THanks
Jason

formula31

I have run the edelbrock torquer 2 cam which is 224,232, .527, .553 on 114 with the Gil magnum choice (which is really close) without reversion. Had the cam advanced 4 degrees too. Worked good with large oval port heads and 9-1 comp.

formula31

The earlier the water gets into the exhaust stream, the greater chance of reversion (water being sucked back into engine). Most silent choice systems result in the water entering the exhaust stream at the same time as stock. Reversion is a results of valve overlap (the intake and exhaust valves open at the same time. Its takes pages to really explain whats going on. It happens at idle. The greater the duration and/or the less lobe seperation, the greater the overlap. Overlap equals reversion, reversion equals broken engine. With dry pipes, no problem. You should consider dry pipes anyway, they are the loudest. Your neighbors and local police will love you.

Jayl13

How bad is it to do a dry exhaust system?
Would it burn the fiberglass at the transom?
WHere does the water exit from in a case like that?
are the dry systems those bassett headers I see for real cheap in comparison to the stellings and cmi's ?
My origional thoughts were to take a pair of car headers, flip them upside down, and bolt them on, if I had to alter the flange a bit then so be it.
I would have to see if that would work though first before buying a set
(old bones cyl head and a header and see if it bolts up upside down)
but that would be a dry system
still dont know where the water would inject back into the pipe though
is heat a problem with dry headers on a twin engine big block boat?
Jason

formula31

Ok, dont try the auto header thing. It only works on totally open boats where the engine is exposed and they use the Basset water injected headers. The dry headers I am talking about are completely water jacketed and the water exits through a nipple at the end of them. Then you hose the water to a fitting on the transom. They are very expensive. You might be able to find some gil manifolds with dry pipes used for a decent price. Location of hole in transom becomes critical then and you may have to use tapered shims to get the pipe in the middle of the hole. Then there are trim rings with silicone gaskets to keep the bugs out.