426 inch+ small blocks

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fcm42000

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What are some of the options regarding large small block strokers?

Anyone have one? What are your thoughts/results?

How much $ and where did you get it?

Hughes has a 426 kit for 2600 bucks, is that the largest you can go in a factory block? I know the race blocks can go to 440 at least.

I know you would need some kick *** heads to make it flow up top, but what if it was in a street car with highway gears and built for the low end? Wouldn't really need overdrive I guess.
 
BPE Crank - 4.125

It will make my 340 block a 430 cube with an overbore to 4.080

It uses a 2" journal so you dont need to have any more clearance then a typical 4" stroke and the cost is probably cheaper since you can go with chevy rods ( 6.200 length ) and as of now your only added expense is pistons

I went with Compstar rods, ( recommended by BPE ) they are lighter then scat's ( 700 vs 600 grams) and are made by Callies.

It's not a " Kit " But I'd call Rod Bloomer @ BPE and discuss your options - he had the best prices and most knowledge of the people I talked to regarding my next step.

Bloomer Performance Engineering LLC
32210 Redfield Street
Niles , MI 49120


Ph. (574) 340-5470
Fax. (574) 272-0807
 
Thanks, I saw you put the ez efi on, I got the single fourbarrel kit.

Dual quads, 430 inch small block....WOW!

What heads and cam are you gonna use? I think with a highway gear in an A body it should still accelerate well.
 
I'm going with an Eddy head, ported, and have not decided on the cam yet. The build is just starting at this point.

I agree about the gear, you'll have more then enough torque curve to handle a highway gear.

I'd suggest again you call Rod, he has a few things that might interest you if you do take this turn.
 
i hear the K-1 cranks are good, with the chevy rods 4.12 about 427" with a +.030 340
 
I just talked to Rod and he said he could make a kit for the low 2k range.

I told him to advertise and he will sell them.

The hughes kit uses the K1 crank 4.18, his crank is 4.2 and uses longer rods 6.2. Dont know if that really matters but just sayin'. hughes kit is also 2699.

I think Im gonna do it but I have fresh 360 with kb107s and it hasnt even run yet. i just want to get around this whole over drive issue, keep a four speed with highway gears.

So what would kb107s with rebuilt rods with arp bolts go for, oh and file fitted moly rings. Is the crank shaft even worth selling, it was just ground 10/10.
 
What about long term reliability? What about the extra stress on the cylinder walls and block that really was not design for a 4 inch stroke?

I put over 2,000 miles on my new motor and it wasn't running until early July last year and went in to storage last Dec. Next season it might see 4,000 plus miles..hard use half of it. Seems like a 4 inch stroke might be worn out at 20,000 miles.

Guess right gears help keep the wear down but then a 7,000-7,500 rpm 340 might not make that much less power than a 6,000 rpm 400 CI.

IMO, the 360 stroke is ok but 4 inch seems pushing it too far to take abuse--unless you are running the HD blocks
 
Are you saying strokers don't last as long? I would disagree with that.

Your milage numbers, anything to back those up? Seem kind of arbitrary and rely on a lot of variables.

BTW, I want low rpm s on the highway, don't want high gears for milage.
 
There are alot of 4" strokers running around - I think that particular issue is blown way out of proportion.

There are a few members here that have higher mileage 4" strokes
 
Ditto on the failure rate. I think there is just a fair amount of core shift blocks being used and overbored without thickness checks being done prior to the build. The issue has been addressed on this site several times before. I met a downstater (from the Niles area) at Red Barn this summer (rained) that's running a K-1 4.125 w/6.2 rods and 11.0 cr in a 360. He drives it everywhere and has almost 10k on the engine. A local shop in Jackson MI built it and according to them dyno sheets showed 545hp. It's a lightweight rotating assembly (comparably) and he stated the stroker kit from Weisco was less than $2400. It was strictly a street driven car no cage etc. For what it's worth.....Sport
 
dodge freak said:
What about long term reliability? What about the extra stress on the cylinder walls and block that really was not design for a 4 inch stroke?

I put over 2,000 miles on my new motor and it wasn't running until early July last year and went in to storage last Dec. Next season it might see 4,000 plus miles..hard use half of it. Seems like a 4 inch stroke might be worn out at 20,000 miles.

Guess right gears help keep the wear down but then a 7,000-7,500 rpm 340 might not make that much less power than a 6,000 rpm 400 CI.

IMO, the 360 stroke is ok but 4 inch seems pushing it too far to take abuse--unless you are running the HD blocks
Click to expand...
The rod to stroke ratio is fine , close to a BB chevy and they run over 100K, wear or breakage problems are due to bad blocks, over reving, rich carb washing oil of cyl walls ect..ect..
 
That's funny. It's only .420 more stroke. You only get half of that on the down stroke so .210 that's less than a 1/4 of further drop in the bore at BDC!
 
But the BB motors are larger, the height, width. So back in the old days, the factory just built larger engine blocks for just a 1/4 more stroke...like its nothing. Even Mopar made the crank mains larger going up a bit in stroke in the 360 motors. What would have Mopar done to run a 4 inch stroke, nothing, I highly doubt it.

To me 10,000 miles isn't much, I sure hope any motor will last that long. Back when I was in high school and the old 60's cars were 10 years old, we all had them running pretty good with 100,000 plus miles on them. Those motors lasted a nice long time back then.

Nope, I'm not rich enough to run back to back tests but common sense tells me the factory's did not make the larger CI blocks much larger than the SB for no good reason. Long stroke engines were never thought of being for high rpm's. The Hemi, the 440 all had 3.75 stroke, why? Few engines had 4 inch stroke, just GM's and one Ford, the 400 ci..Fords 429 which was bad ***, had just a 3.59 stroke. The Ford 400 ci was never thought of as a HP engine. They were for trucks and vans, not sport cars.
 
Thinking more about high stroke motors, the pistons rock more at TDC with higher strokes. Plus using a 4 inch stroke in a SBM..any SB.. means you have to use a shorter piston, which will rock in its bore even more so.

Maybe the engine won't break but the ring seal is not going to last as long as the short stroke/long skirt pistons and its going to burn more oil.

But hey, most people now baby the heck out of their rides, its more for show than go. So many are getting away with 4 inch strokes, I guess. Doing 360's in the rain/snow is a thing of the distance past, lol
 
I would also be concerned about long term life with the longer rod and longer stroke. Once a piston gets shorter than about 150" compression height, ring seal is dramatically reduced. Not a problem in a race engine but a street engine... What about using the 5.7 rod and adding that on the piston? I don't know about counterweight clearance but something to think about.
 
Dodge freak has a point that has become moot over the years when you realize that the factory has to make an engine that they know will last for the public. When we stroke our engines, there not truck engines, not passenger car engines or excellent Hwy. way mileage getters.

Other things over the years that used to have this same discussion are things like Aluminum heads, roller cam shafts, Fuel Injection. (Remember the ol'mechanical stuff?)....etc.....

DJVCUDA is dead right on. This has been talked about a gazzillllllon times. The engines will run fine for a long time if you do two things, build it right and don't kick the snot out of it. But then when did you spend all that money for. To drive it like a baby?!?!?!?!
 
the 4,125" stroker requires a 6.200 rod minimum to clear the counterweights.

you can go longer, but at 1.33 CH @ Zero deck @ 9.6 I would not go longer.

1.33 is the same CH as the LS series chevy engine - they last over 100k
 
well, I am....

The crank which is 4.125" is from last year, which is a newer design then the LS series engine I am referring to.

about the only 40 year old technology is the block's dimensions - and guess what? The block does not know what year it is!


I was referring to compression height of the pistons and the ability to live long term, and I still stand by the fact that if an LS series engine can have a short CH , then so can ANY motor, regardless of what year the block was originally cast.
 
75Sport said:
Ditto on the failure rate. I think there is just a fair amount of core shift blocks being used and overbored without thickness checks being done prior to the build. The issue has been addressed on this site several times before. I met a downstater (from the Niles area) at Red Barn this summer (rained) that's running a K-1 4.125 w/6.2 rods and 11.0 cr in a 360. He drives it everywhere and has almost 10k on the engine. A local shop in Jackson MI built it and according to them dyno sheets showed 545hp. It's a lightweight rotating assembly (comparably) and he stated the stroker kit from Weisco was less than $2400. It was strictly a street driven car no cage etc. For what it's worth.....Sport
Click to expand...

I'm with you on this even with sonic check I would be hesitant to go with more than 30 over on any block.
 
I agree. When a company makes a production commitment (GM) for a 4 bolt cross bolted bottom end and a new head design this engine's longevity becomes a byproduct of the engineering. It's no wonder the LS series is an easy build to 500hp. IMO Chrysler engineering attempted to keep up with the new gen hemi but I would have preferred an LA updated design with better heads and a stronger bottom end. I'm not cruising for arguments but I feel the boat was missed big time in this area.
 
So the higher the pin is on the piston the more it rocks? This is a fact or opinion? kinda seems like it would be the opposite.

LS engines use the same geometry (pin height) and it works ok for them, they are also aluminum blocks (car). So it is ok to compare the two, like he said the block doesn't know what it is.

As far as the block not be able to take it, because of the geometry, not sure any of us are on a level education wise, to know that. If you have seen specific examples of the high piston pin causing problems thats one thing, but to speculate, well, anyone can do that.

Has any one run one or seen one run?
 
just look at the clearances on an LS engine. everything is tighter then a nun's asshole. also, look at oiling system & take a closer look at
the pistons they use. if one tried to run clearances like that on a LA block
it'll fry itself pretty fast. bottom line, you can beAt on a 500+hp 427cid
LS series engine and it'll last for years & years. try doing that with an LA
stroker. not dissing mopar.. but facts are facts.
 
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