I think ….. he assembled the parts himself. I don’t think this is off the shelf.
400/426 Stroker. Ever heard of one?
- Thread starter slimjim
- Start date
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33IMP
Well-Known Member
Yep. Crank work on a stock 383 steel crank, long big block Chevy rods, and (apparently) some off the shelf 440 stroker pistons set up for bbc pins. The trick is finding workable pistons, and then drilling the block to fit.
I like the Idea of a 426/400 perfect size for 500 hp, should make peak in high 5000's rpm, a good spot for a street strip type of build.
I won’t ask: why not just build a 440. But a low deck will fit not necessarily better but easier. Kim
slimjim
Well-Known Member
Not necessarily after fit. The lighter weight is a plus but, I’m mainly after engine characteristics. I LOVE the free spinning nature of the 340. I’m hoping to achieve the same characteristics with extra cubes for a bigger punch
DV did a few small block chev rod lengths shootout each made little more hp than the last I think it was 7-10 hp from shortest to longest if I remember right. I like the idea of ideal bore rod and stroke ratios but wouldn't say necessarily needed for most there's a lot of low hanging fruit to go for 1st to make easier power.
Can u post what rods and pistons used? I can have a crank machined to any undersize and offset stroke I need. Thanks. Kim
Years ago 20 to 30 years ago, there were some racers out in the west coast area who did a ton of experimentation with off set grinding B and RB cranks for big cubic inch engines. I used to know some of their names, but I'll bet most of them have gone to the great race track in the sky. The reason I say they maybe gone is, I was in my 30s to 40s at the time and they were at least 10 to 20 years old than I at the time. I'm now 71 and can't recall seeing or hearing from, or about them for years now.
You’ll get the 340 feel for sure. It’ll be very similar since it’s a big bore short stroke deal. Just 86 inches greater.
Long rod more HP?
It’s unfortunate when the old timers is pass on. I hope they are in the great race track in the sky. Having fun! The problem is a lot of the little things the experimented on, they probably didn’t even write it down. A lot of the old timers, they did things and kept things in their head.
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Yes Sir
slimjim
Well-Known Member
I’m using Icon pistons with a 1.48 compression height and Scat 6.70” rods. Turned the rod journals down to 2.2”
33IMP
Well-Known Member
I like your plan. Lighter crank (slightly) lighter rods (than 440s) lighter forged pistons ( compared to cast stockers, WAY lighter) lighter pins. Should rev like mad, better than a 383, and probably a 340.
You will need really good heads and the right camshaft to allow it to make power at those high revs, however.
Interesting build. Problem with standard stroke 400s has always been pistons, your build solves that without building a big stroker.
Have you checked out that 8000 rpm 327 build on engine masters? 7500 rpm 426 should be fun.
Very do-able with off the shelf parts. ICON IC825 +.033 , BBC con rod @ 6.700. about .027 below the deck, ample under piston pin to counter weight clearance. Only thing to be questioned would be the con rod big end width size discrepancy. 1.012 BBM, .992 BBC yielding a .040 extra side width.
Extra clearance is not a big issue from what I’m told.
There have been thousands of 400 blocks built into 470's using offset 440 crankshafts (that's what you did 30-40 years ago) no issues with using a BBC rod that creates .018" extra rod clearance. I see no reason that it won't workout fine. This engine will easily spin another 1000 rpms before it runs out of cylinder head like a 500" engine combination would.
Tom
Tom
What rpm do you plan on running at and with what head and valve combo?
RAMM
Well-Known Member
Yes I've heard of it. In fact I have one i'm building for my bodyshop buddy's '72 RoadRunner. I turned a 383 forging to 3.545" stroke x 4.375" bore= 426.33 ci. I'm using a 6.7" Rod with a Mahle piston with a 1.32" CHT. < Correction it is a 1.480" CHT-I've got a lot of builds going on--LOL.I've got a nice solid lifter Hughes grind going in it. The plan is to build HP up to and beyond 7000 rpm for some roadracing style fun. The bottom end photos show how the short stroke and long rod doesn't pull the piston skirt out of the bore at BDC. Judging how easy this thing is to turn over I think this should make some power AND last a long time. J.Rob
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RAMM
Well-Known Member
The bobweight is very low--like small block low. J.Rob
Nice gear drive set up.
Whatcha doin for a camshaft?
Who’s rods?
Do you have a piston part number?
That looks great. Keep us posted on the build. (separate build thread?)
RAMM
Well-Known Member
Just going off the top of my head since I'm not in the shop. Cam is 256/260 @ .050" .580"/.585" 111 or 106 I think.
Eagle 6.7" H beams
Mahle 929962575
I think the bob weight is 1850 or 1950 grams. J.Rob
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