Looking to build a 4.25 stroke SB

[JJFIVEOH]

Has anybody in here had any experience yet with the 4.25 stroker cranks that have been produced recently? I'm looking to build a torquey bracket motor with no more than 11:1 comp. and a Dart block. I know that the 4.125 stroke cranks have been out for a while but the 4.25 is relatively new. I'm looking for a mid 10 second motor in a 3500 pound car that will last, week in and week out for a few years without having to do major maintenance. I'm looking to do this because I like to be a little different than others, yet still serve a purpose. I've researched pistons and cranks and heads for this combination. The car is all set up to run a big motor like this, and usually sees around 300 passes a year. Since I race every single weekend, I need a motor that can move 3500 pounds, not turn excessive RPM's yet be dependable enough to last for a while yet not needed to be worked on more than a couple of times a year. I have a few things in mind, and I can go into details if you need, but I just was wondering if anybody's actually built a 4.25 stroker motor.

 

[JJFIVEOH]

Anybody with stroker motor experience?

 

[90mustangGT]

That is a lot of stroke. I don't have any experience, but I know your going to need a really deep dished piston. I guess that stroke is new, so little info in known. What would that be, a 43X-450cid small block???

 

[dragnazz5.0]

gonna need like a 9.5 inch deck or some really funky looking pistons with the wrist bore way down at the bottom

 

[bluevenom867]

JJFIVEOH

Go look at World Products 427 or 460 shortblock (its called the Harcore shotrblock or something).

New Man-O-War block,4340 Eagle crank,Eagle H-Beam rods with ARP L19 bolts,and Mahle pistons.

Pretty damn beefy for a mail order short block!The only thing I dont know about is the Mahle pistons...I hear their good though.

Heres their catolog page: http://www.worldcastings.com/docs/05_cat_pg42.pdf

I would do the 460 shortblock,then put whatever heads,cam,and intake/carb combo you want on it.

 

[JJFIVEOH]

I know that JE makes a 4.125 -30cc dish piston that would make the compression 11:1. A 4.125 piston with a 4.25 stroke would make a 454 CI motor.

 

[JJFIVEOH]

JJFIVEOH

Go look at World Products 427 or 460 shortblock (its called the Harcore shotrblock or something).

New Man-O-War block,4340 Eagle crank,Eagle H-Beam rods with ARP L19 bolts,and Mahle pistons.

Pretty damn beefy for a mail order short block!The only thing I dont know about is the Mahle pistons...I hear their good though.

Heres their catolog page: http://www.worldcastings.com/docs/05_cat_pg42.pdf

I would do the 460 shortblock,then put whatever heads,cam,and intake/carb combo you want on it.

I'll have to look into that. I like that 460. I was looking at an Eagle crank and H beam rods to start with. Thanks.

 

[bluevenom867]

I know that JE makes a 4.125 -30cc dish piston that would make the compression 11:1. A 4.125 piston with a 4.25 stroke would make a 454 CI motor.

With what cc head is that?

Whats the compression height and rod length for that combo?

 

[bluevenom867]

I'll have to look into that. I like that 460. I was looking at an Eagle crank and H beam rods to start with. Thanks.

We got Eagle stuff in our 427 (with JE pistons) and plan on some big power.

Should handel the 450hp shot of nitrous no problem (and thats jsut the fogger,hehe)

I would estimate the crank good to 1500hp (taken it easy on the tune of course)

The rods with thous bolts (same as we have in ours, 7/16" 12 point cap screw ARP L19) are probably in the 1200hp range.

And the pistons depend on the tune.

 

[JJFIVEOH]

DAMN, Im not looking for something that wild, lol. Im looking for a bracket motor. I figured the 11:1 with the 58 CC AFR 225 head. Not quite sure about the compression height, Ill have to look it up, but this is with a 6.25 rod.

 

[bluevenom867]

DAMN, Im not looking for something that wild, lol. Im looking for a bracket motor. I figured the 11:1 with the 58 CC AFR 225 head. Not quite sure about the compression height, Ill have to look it up, but this is with a 6.25 rod.

Just pointing out that Eagle is some good stuff

Yea,the 11:1 sounds right,only thing is I wonder who much the pin intersects the oil ring groove?

 

[JJFIVEOH]

Yeah, me too. Is why I was looking to see if anybody has done this build before. I want to know what I'll be getting myself into before I do it, lol. This kind of stroke is a serious motor, but I think if it can be done without any glitches as far as clearances, (I know Ford motors can be stroked easier than Chevy's) then it could be a real sweet motor. An easy 600 HP without tearing it up and lasting a few years.

 

[dragnazz5.0]

a 4.25 stroke with a 6.25 rod? thats crazy man. there is a company out there that makes pistons with the wrist pin that goes through the ring grooves and here is a plug that pops in the hole to complete the grooves all the way around. not sure who makes it and im sure they arent cheap but its worth looking into

 

[bluevenom867]

a 4.25 stroke with a 6.25 rod? thats crazy man. there is a company out there that makes pistons with the wrist pin that goes through the ring grooves and here is a plug that pops in the hole to complete the grooves all the way around. not sure who makes it and im sure they arent cheap but its worth looking into

Yes,the pin intersects our oil ring with a 4" stroke and a 6.250" rod (1.24-5" compression hieght).

They use a flat ring (they call it a spacer or something,Ill look tomorrow I got the pistons/specs here) thats goes in between the oil ring.

These were custom order JE pistons,btw.

JJFIVEOH,the only clearancing we had to do was at the bottom on the cylinder walls (to clear the rod blots),one section of the pan rail,and with a 4.25" stroke you'll probably need to watch out for the oil pump (i.e the crank counterwieght might need shaved,or an oil pump spacer?).

 

[JJFIVEOH]

What block were you working with?

 

[bluevenom867]

What block were you working with?

Dart Iron Eagle 9.5" deck with Cleveland mains.