Small Block Stroker Build

[the_engineers]

I'm contemplating a stroker build and am hoping for some insight. I have 2 340 blocks, 1 is an uncut '72 and the other is a .030 over '70.  Both will be sonic-checked so that I know what I'm working with.

I've been looking at the 4.125 stroke crank that retails for about $700 and uses SB Chevy rods. Given that, I'm figuring on using 6.125 rods and hoping for .030 over on the '72 or .040 over on the '70. Either would put me in the 430'ish range.

Rest of the motor would mostly be re-using my current set-up...Edelbrock heads that I'd like to send to Shady Dell for their CNC pattern, Air-Gap RPM intake, Lunati 60403 cam, Hooker 5115's.

The motor would be pretty low rpm and the car gets used for enthusiastic cruising, for the most part.

I've got an A518 going in this winter, so I'm in the market for a converter. Any thoughts?

Comments? Suggestions?

[mojavered]

No thoughts on the converter, but would talk to someone at Hughes Performance in Arizona or another professional co.  But I do like the "enthusiastic" driving

[Chryco Psycho]

The 408" is an easier build for what you want to do but 426 CI is reachable , you will have to clearance the block for the long stroke crank , downside you wallet will be lighter other than that I would be all over it !!

[kielbasa]

BPE sells a 4.125 crank, 6.2 rods with .927 pin and matching pistons.......quality stuff for great price.
skirts might be a little short (to clear counterweights at bdc) with the 6.123 rods if you choose to go that route.......

[wally426ci]

Just make sure that you know exactly what you want. I am planning on downsizing my stroker via cam & converter b/c I am sick of lumping along at red lights.....

sounds funny i know.

[Chryco Psycho]

Just make sure that you know exactly what you want. I am planning on downsizing my stroker via cam & converter b/c I am sick of lumping along at red lights.....

sounds funny i know.

what cam did you use ??

[Jim]

Been working through some bugs on my 360/410, but I'm really digging it for a street motor. With a relatively stock top end (J-heads & T-quad), Comp Cams XE274H, a 2800 stall converter, and 3.55 gears, wheel spin is just a blip of the throttle away.

That being said, I really don't think the extra stroke and displacement is worth the hassle to get to the 430".  If it's a street motor, going with the 4.15 stroke, you're just looking for bragging rights.  You'll be dealing with more clearance issues (there are none with the 4" cranks and Scat I-beams), and more side load on those thin 340 cylinder walls.

[Chryco Psycho]

I generally tend to agree with this a few more CI is not nessisarily worth it from an engine life & clearance . ring seal etc point of view + on anything less than a max effort build I doubt you would feel the difference in power , you would have lots at 408 CI

[the_engineers]

The reading I've been doing says that with the smaller 2.0" rod journal, the clearancing for the block shouldn't be any worse than on the 4" stroke crank with Mopar rods. Seems like the preferred for the 4.125" stroke uses the 6.200" rod. I can price out both, but if the costs are close, it seems worth the extra 20".

[Jim]

Stock rods do require clearancing with 4" crank. Aftermarket (Scat) I-beams do not.

Obviously, check your piston cost too. Lots of off the shelf pistons available for the 4" stroke. Not sure what's out there for the 4.25".

[wally426ci]

what cam did you use ??

I will post specs when I get a look at the card....