502 to 540 ??
 

I have a modded 502 that i think could use some refreshing this winter. I was thinking of stroking it , im assuming thats what required to make it a 540? What does it cost to stroke the crank and what HP/Torgue gains would be seen? Thanks guys..sj

Check out www.speedomotive.com

The Speedomotive catalog shows a 4.375 stroke in a standard deck block. How durable is this? The oil ring would be way up on a short piston.

Here is a discussion:

http://www.offshoreonly.com/forums/s...threadid=52857

Just converted my blown 502's to blown 540's. Went from a 28 pitch to a 30 and was still on the limiters. I've been on a normally aspirated 35 fountain with 540's that ran 93 on gps.

My boat weighs over 10K empty, for me the change was well worth the $'s.

Conventional wisdom would indicate that a 502 into a 540 would be less than ideal in a marine application. Lets see....piston with a short skirt in a bore with larger than normal clearances to begin with = piston rock...comprimised rig pack in an application with high cylinder temps...less piston dwell time in an duty cycle where detonation is more prevalent. I think these things probably run fine, but not as long. A tall deck block would be ideal...all it takes is money:cool:

No I can't tell you how many short deck 540's,,and 565's we've done and how gret they are they work super and are bullet proof
tons of power and live just fine ,,,,4.25 stroke ,,,250 long rod,,, 4.5 or 4.600 bore piston of the shelf at J&E (stocked),,reverse d shape if blown 8.75 comp or flat if N/A and 9 to 1 ========
ITS WORTH EVERY CENT ,,we have the stuff in stock as well :D :D

ONCE YOU GO 540 YOU WONT GO BACK

No Troubles here....
 

Gen VI short deck, Crower 4.25 rotating assembly w/6.385 rods, JE blower pistions, 9.25:1 CR with aluminum heads, 6-8 lbs of boost (depending on elevation) with an intercooled M3 ProCharger.

So far, So good
BTW, tons of bottom end torque :D

ITS GOT to be fast great combo !!!!!!!!