500 bulldog question
 

Does anyone know what size cranks that mercruiser used in the earlier 540s, 4.25 or 4.375

the stroke is 4.375 and the bore is 4.440.its a good combination.

yeah 4.375 and with that rod I could not find any shelf pistons so when you bore it. you need custom pistons. Couple extra bills and lead time. I went with Diamond Pistons.

Don't mean to hijack but would like your opinion on the best combination .

how about 4.5 by 4.5.572 cu in.

j&e makes them for me,5 bucks a piston more than shelf piston,and i have them in 10 days.

i know where the last one that was built is and its still brand new on the pallett waiting for someonr to buy it..he wants like 14 k for it..serpitine set up carb to oil pan less theexhaust..

Thats what happened to me with the 557s which started life as 500bulldogs i like that combo. The ones i have now has 4.25 cranks with bowtie tall deck blocks.

4.750-4.750 + 673:wuerg019:

I guess what i should have ask is how many ci's can be had from a Merc Blue 502 and still be reliable making 700+ n/a .

fixx
 

565 cid

Thanks Fix . Why build a 540 when a 565 can be had . What combo of stroke and bore .

it depends on what year your engine is,some 502 blocks are thin and should not be boared more than .030 over,that being said,a std deck 9.800,with a 4.250 crank is 540 cu in,but if it is a thin wall block,if it needs to be boared bigger at rebuild time,you need a new block.and as far as 700+ hp from a pump gas 540,700 is pshing it,buy with the right parts itcan be done.imo,650 is more realistic,and safe.

I disagree mike, there is this guy in Texas that builds 540s.............

Ah, nevemind :D hahaa

Wish you were closer, my 575scis are coming out in a few weeks

Thanks Mike , if memory serves me my HP was built in 1998 . Is that good or not so good ?
Sorry about the hi-jack J boatman .

its the john deere green paint,good for 100+xtra hp :lolhit:

your 1998 is a gen 6,it is vastly improved over the gen 5 502 block,if you have a 454,it has a 4.250 bore and i am not knolegable on them.

nevermind

fixx
 

room forboring in case you score a cylinder but like mike said theirs certain blocks you can do it to..the block must be sonic tested first for thickness,,you have to keep the explosion contained in the cylinder,if the cylinder walls are to thin the it asts like a granade and then you know what happens ...

You should have the Gen VI block if thats the case. Thats better than the Gen V. Usually they can take a bit more boring, but overall a better foundation.

The very early merc 502 mags and HP465's, like 1990-1992 used Bowtie blocks, mark iv style. Those are good foundations.

IMO, when building, keep the bore size minimal to keep as much meat for future rebuilds. The extra .030 or .060 isnt gonna make magic happen. Sure maybe on some builds it might gain 10,15, 20hp, but theres better ways to find that power without compromising the integrity of the block, unless mandatory.

Its not that far, and Mike always has a cold beer handy in the shop fridge waiting for ya.

Plus, while he's freshening and building your motors, you can get the stock blowers over to Darren Meyer in Michigan. He knows those blowers well and does several mods to them that helps make them more effecient, and very reasonably.

Thunder , Thanks for the info . I am a newby when it comes to strokin bigblocks and like to gather all the info i possibly can before starting a build . Also will be consulting Bob Madara .

A good combo for a GM production std deck 502 block, is a 4.25'' crank, 4.500 bore. A 540CI.

Larger bore with that stroke, imo, is better left to the bowtie, dart, merlin blocks. Like 555/565ci. More stroke than you need the tall deck block. You dont want to have to run pistons with the pin to far up to compensate. You want a decent rod angle also.

:D

Is Darren Meyer DPME? If so I have already talked to them, and am sending the blowers out soon. Going with teflon stips as well, smart people when it comes to blowers.

This is the kind of info i was looking for , thanks .

Yes, that is DMPE.

When stroking, I have heard it all about the rod ratio...

http://www.chevytech.com/2c27o1.html

:readinghelp:

fixx
 

rod legnth,,helps put less pressure on the side of the cylinder walls..the only number you need to worrie about is for your 540 which is 6.385..i would just sell yours as a whole and start with a stronger block..you will be better off in the long run..think about it,whats your engine worth now? 5k..your going to tear it down,and not use anythinf but the block and maybe get 1200 for the old wore parts..a dart block is 2300??then the rest of the goodies..add it up..

Valid point . If i sell my HP a 598 would replace it . :hijack: Gotta see trips with the cat and trying to decide the best way to get there . Blowers are great but seems to be a whole lotta other issues that go with them . I,m starting to wonder if it would be better to just freshen the HP and hang a blower on it . :daz: 871 and two fours . Hmmm , what to do.......

fixx
 

you would make more power with a m4,,better on fuel also if you can keep out of boost..