Thread: question about stroker cranks

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can you use stock length rod on stroker cranks? 4.25 stroke with a 6.135 rod? i have seen most stroker kits come with 6.385 rods i think. Whats the deal?

Pat may have more to add, but the basis of it is that the longer rod will put the piston skirt farther away from the crank counterweights with the piston at the bottom of the bore. Could be a collision otherwise.

oh i see that makes sense. well does that mean you could use normal pistons as long as you use the longer rods or do you have to lower the compression height as well? i'm not sure lowering the compression height means what im trying to say. what i mean is shortening the distance between the centerline of the wristpin and the top of the piston. is that lowering or raising compression height?

you can use a 4.250 crank as long as the crank is cut for short rod 6.135 i done many the piston for lower buck i use hyper speed pros with the stock 6.135 rod you will have to go with external bal just like a 454 the ch of the piston need to be for the 4.250 and 6.135 rod and for the 9.800 deck block

what do they do just relieve the counterweights on the crank? what would the CH need to be? What is the formula for finding CH?

yes the counter weigth is cam cut for short rod and you buy the crank that way .not to hard to find out EZ math or if your lazy just go on JE /SRP web page and look it up .the math is 1/2 the crank 2.125 + rod 6.135 = 8.260 - deck 9.800= CH of 1.540 if 020less then 1.520 CH this has alot to do with the make of pistons like ROSS Piston will not always have the same CH has others like SRP

so basically you would order a crank with 4.25 stroke and tell them youre using stock rods and then get pistons with a 1.54 CH? Does deck height come into play? I guess you would have to subtract the amount of deck you shaved off for the actual deck height, like if you zero deck your deck height would change right?

Originally Posted by slammed84

so basically you would order a crank with 4.25 stroke and tell them youre using stock rods and then get pistons with a 1.54 CH? Does deck height come into play? I guess you would have to subtract the amount of deck you shaved off for the actual deck height, like if you zero deck your deck height would change right?

well if you building a hi rpm engine i like the 6.385 rod this helps in two ways one is it can go internal but thats not a very big deal but if you thinking buying new rods and forged pistons and forged crank then i go 250 longer. i used the cast steel cranks and forged steel as well that are cut for the 6.135 rods. but the cast steel cranks and hyper pistons for lower $builds i use the gm truck /rod thumb rods or the scat I beams work good to but the cost is same for the 6.385 s .i do not deck the block till pistons are in hand like i said some of the forged pistons are not always the same CH . but like i told you. buy your pistons for a 489/496 if you building 030 to 060 over with the 4.250 crank and the 6.135 rod . in custom pistons you can get the deck were you want but with a 1.54 not every shelf piston many not give you a O deck if you deck the engine to lets say 9.780 so i look the piston up first before it gets deck. if you know the piston CH it is EZ math . then i deck the block to what ever i want

do you know who sells a good cast crank and how much $ are they/ how much power can they take? I found a nodular iron 4.25 crank for $245, is that a decent deal? I just weighing all my options and if I could make a 496 for $300 more or so then why not? So if I get the crank then order it for stock rods (mine are in good shape) then by using the math figure out what CH i need in a domed piston. Probably go with those hyper speed pros you were talkin about. Then depending on how far that setup sits in the hole will determine how much to zero deck, right? Do you think I would get the same results If I left them .010 or .005 in the hole, still have good quench right?

Originally Posted by slammed84

do you know who sells a good cast crank and how much $ are they/ how much power can they take? I found a nodular iron 4.25 crank for $245, is that a decent deal? I just weighing all my options and if I could make a 496 for $300 more or so then why not? So if I get the crank then order it for stock rods (mine are in good shape) then by using the math figure out what CH i need in a domed piston. Probably go with those hyper speed pros you were talkin about. Then depending on how far that setup sits in the hole will determine how much to zero deck, right? Do you think I would get the same results If I left them .010 or .005 in the hole, still have good quench right?

you will have to shop a round. i am dealer for parts so i can not tell you were is your best deal is. the cast steel scat crank can take as much power as the stock rods will and more. the cheaper speed pros i used the hi ch and low ch pistons ..yes if you know your piston ch then with math i deck the block . were i put the piston has abit to do with how thick of a head gasket i use . older blocks i use the 1017-1 felpros so there around 005 to 0

with a 4.310 bore can I use a head gasket with a 4.37 bore or 4.38? Or is that too small? also is there a difference in marine application head gaskets? With.039 compressed thickness I would need to leave .005 in the hole right? that would leave .044 Piston to head clearance.

Originally Posted by slammed84

with a 4.310 bore can I use a head gasket with a 4.37 bore or 4.38? Or is that too small? also is there a difference in marine application head gaskets? With.039 compressed thickness I would need to leave .005 in the hole right? that would leave .044 Piston to head clearance.

you can use the smaller bore if you want i use the 1017-1 were are you getting 044 ? you can run any thing you want your the builder. i have run them any were from 0 to 010 in the hole with a 1017-1.you do not have a boat? so you realy do not need them but i have. there is things i do to the block to use them i re work the deck and if you look around hear you will find every thing you need to know . i am done

Originally Posted by pat mccarthy

you can use the smaller bore if you want i use the 1017-1 were are you getting 044 ? you can run any thing you want your the builder. i have run them any were from 0 to 010 in the hole with a 1017-1.you do not have a boat? so you realy do not need them but i have. there is things i do to the block to use them i re work the deck and if you look around hear you will find every thing you need to know . i am done

i'm getting .044 from .005 deck clearance + .039 gasket = .044 piston to head clearance. I just asked about marine gaskets because I saw them and wondered if they were different in some way. I don't mean to bother you, if you don't want to answer questions then don't bother, not gonna hurt my feelings dude. You seem to know what you're talking about and you usually reply, so I ask.