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426 Stroker, is it OK to supercharge?

Posted By: hudsonhornet7x

426 Stroker, is it OK to supercharge? - 09/26/18 05:50 PM

Manley makes a nice 426 stroker kit for the Gen III engine. If you put one into a BGE block with a positive displacement supercharger ( IE Hellcat), would that make a nice combination? Or would side loading of the cylinders, lack of crank overlap, etc be a detriment to supercharging?

Thank you
Posted By: knyech1

Re: 426 Stroker, is it OK to supercharge? - 09/27/18 03:44 AM

Ppl do it all the time. Tons of stroker Mopar, Ford, Chevy, import stuff that is heavily boosted. The long rod shorter stroke is great, but because of the limited swallowing capacity versus the stroker, you have to make up for that in RPM. If the valvetrain can't take it, then a stroker with lower RPM would be a high power solution. You could always try to get the best of both worlds and run a long rod stroker engine.
Posted By: WO23Coronet

Re: 426 Stroker, is it OK to supercharge? - 09/27/18 04:10 AM

That works out to a rod ratio of just over 1.5 and a compression height of just over an inch. Getting kind of tight but doesn’t seem terrible.
Just to point out, Mopar shortened the stroke of the 6.4 when they made the Hellcat. I know they have a lot of other things to concern themselves with (it lasting 200K, warranty etc) but it’s food for thought. If you already have the kit I say use it, if you don’t, I’d keep the stroke where it is.
Posted By: mdeane

Re: 426 Stroker, is it OK to supercharge? - 09/28/18 02:10 AM

Seems to work well enough that Edelbrock offers it as a crate motor.
Posted By: fbs63

Re: 426 Stroker, is it OK to supercharge? - 09/28/18 12:54 PM

Really depends on your goals. 8-10 psi should not be a problem. More than that I would shorten the stroke and rod to get a taller compression height piston.
Posted By: ric3xrt

Re: 426 Stroker, is it OK to supercharge? - 09/29/18 03:55 PM

FC lowered the stroke on the Hellcat so they could get a 1.28 comp Ht more material above the pin so they didn't have to go high end after market for the piston,
Both the SRT392 and the Hellcat use the same length rod(6.20)

A BGE based 426CI stock 4.09 bore and 4.05 stroke with a 6.125 rod(1.51RR) use a 1.12 comp Ht piston, Arrington, Muscle Motors Xtreme,
Seidle Motorsports, and a few others offer this combo for boost applications...soooooooooooo it must be working.
I'm redoing a Arrington alum block 440 ,4.16 X 4.05 ,6.125 rod 1.09 Comp Ht , Ken Bell supercharger ,after 30K miles @ 10 psi #3 cylinder sleeve split.
Just bought a 426CI based 6.1 short block (4.08X4.08) 6.125 Rod 1.88 Honda journal .866 Dia pin ,had 1.065 Comp Ht JE's everything that every one says not to do .. they did and ran 18psi with a Whipple 2.9L supercharger...since April 2016, 22kmiles on it...split the bore in #1 up at Beaver spring this past May....if you want longevity..this is not your combo, I bought it to see if I can use Darton sleeve Mopar part # P4510316
This past spring we did a BGE based 427CI , 4.125 X 4 with a 6.125 rod a 1.14 comp ht(1.53RR) 4.5L whipple...cracked the Hellcat head...short block was fine...

With todays metallurgy 1.09 Comp ht(1.5 RR) is about the lowest you should go and survive with low boost (6-12) anything higher you should aim for a minimum of 1.12 comp ht.

There are quite a few 03-08 5.7 based "392" pushing 14-18psi with a 4.05 crank,6.125 rods and 1.09 Comp ht, granted it's a 3.917-3.957 piston, smaller surface area, so it'll handle the pressure better than a 4.09
Posted By: fbs63

Re: 426 Stroker, is it OK to supercharge? - 09/29/18 04:24 PM

My personal opinion is the early 5.7 is the best choice for boost. Thick cylinder walls and a smaller bore. Better for complete ignition of the boosted mixture. Top Fuel motors are 4.310 x 4.500. There's a reason they run the small bore.
Posted By: ric3xrt

Re: 426 Stroker, is it OK to supercharge? - 09/29/18 07:18 PM

Originally Posted By fbs63
My personal opinion is the early 5.7 is the best choice for boost. Thick cylinder walls and a smaller bore. Better for complete ignition of the boosted mixture. Top Fuel motors are 4.310 x 4.500. There's a reason they run the small bore.


Before the BGE/Hellcat block, I would agree 100%, leave the 6.1s and SRT392 blocks to the NA crowd. Now A budget build lower RPM 400CI and under, your a head of the game if you use the older 5.7 block.....you have a better chance of liftting the heads before you hurt the older block...with good internals.

Higher RPM Short stroke build 380-410Ci the BGE would be a great block to use , look at the power the Hellcat/Demons are making.

3.9-4.00 inch bores are what a lot auto manufactures are using and have gone to , it's a better bore size to keep emissions down.

Interesting point about the Top Fuel , Bore/stroke ratio equals .957, Bore stroke ratio for the 5.7 based "392" 4.05 crank is .967 and 4.08 is .957, to get that with a stock 4.09 BGE/Hellcat you need a 4.25 crank(.962) need a 6 inch rod to get a 1.14(1.15 zero deck dry) Comp Ht, and 6.07 length rod gets you a 1.08ish..but both are horrible Rod ratios
Posted By: hudsonhornet7x

Re: 426 Stroker, is it OK to supercharge? - 09/29/18 07:51 PM

I appreciate all the back and forth on this subject, engine math and theories are fascinating.

Our decision has been made. We will be going with a stock stroke Hellcat crank. BGE block, and Manley rods with Diamond pistons and H-13 wristpins. THe block will also get ARP studs and a line hone along with all other necessary machining to make everything square.

A2 Speed is building it and claims that this short block will more than handle the heads and blower we have.

Thank you all again.

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