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Stroker crank...

tarafied1

tarafied1

Well-Known Member
The 429 short block was pretty much stock (except for the cam). I did have TRW flat top forged pistons but the block is a standard bore and the crank has standard size journals. Both the block and the crank need machining. The crank is scored from what looks like trash generated from the rocker arm failure. I think it could be cleaned up easily. The cylinder walls have some slight scoring. Again probably could be cleaned up. However, I would like to have these things cleaned up by machining them. The block could be bored maybe .010" over, I'll let the machine shop tell me what it will take. Since I need new pistons, I have considered using a 460 crank. The 429/460 use the same rods but move the wrist pin location for the different cranks. Then I started pricing a 460 crank (unless I could find a good used one), Scat makes stroker crank kits for the same cost as s standard 460 rotating assembly. Sure I could save money just getting the crank and pistons and reuse my old rods. I could save even more by just having my 429 crank reground (maybe, haven't checked the cost of that). However, 385 series blocks can be stroked to 4.5" without any mods. So I could have a 557 cubic inch big block for just a little more than a stock rebuild. The balancing will maybe be a bit more but either way I go it will need to be rebalanced. I can get a Scat cast 4.5" stroke crank, forged rods with ARP bolts and Forged dished pistons (to keep compression in the 10:1 range), rings & bearings for about $1,500. I spoke to my machine shop guy and he can balance everything with my flywheel and even pressure plate. Won't know cost until he's done due to how much weight needs to be added but in the couple hundred and up range. So about $2K plus the cost to bore and hone the block. Let's say about $2,500 I could have the short block all done and have a 557! Over 100 more cubic inches in the same package.
 
Someone's got a bad case of 'while I'm at it' , been there before and it's addictive... wish I had any parts to donate but I'm still playing with small blocks.

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If everything else you have will hold up to that torque and power you'll make then why not. Fuel economy never has been a goal anyway lol.


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Jonk67 said:
Someone's got a bad case of 'while I'm at it' , been there before and it's addictive... wish I had any parts to donate but I'm still playing with small blocks.

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Click to expand...
yes I do... but isn't that the way you are supposed to do things?!?!
 
it depends on what your plan for this motor is ultimately. if i were in your position, i would probably build a 514 motor, instead of a 557.
 
tarafied1 said:
why 514? is there an advantage?
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i like the shorter stroke and better rod/stroke ratio. i also prefer the better balance between low and and top end power. the 557 makes great low end power, but gives up a lot of top end power. the 514 makes good low end power, as well as good top end power.

in the end it is personal preference anyway.
 
rbohm said:
i like the shorter stroke and better rod/stroke ratio. i also prefer the better balance between low and and top end power. the 557 makes great low end power, but gives up a lot of top end power. the 514 makes good low end power, as well as good top end power.

in the end it is personal preference anyway.
Click to expand...
what stroke is the 514 crank? I found a 521 kit which is 4.3" crank and .030" over
 
rbohm said:
the 557 makes great low end power, but gives up a lot of top end power. the 514 makes good low end power, as well as good top end power.
Click to expand...

How would you ever tell the difference between 6 gazillion or 7 gazillion horsepower?
Me i say go the 557. Mainly because its bigger than everyone else's.
 
So here's the thing on stroker engines...they make gobs of torque at the expense of high rpm horsepower. That's a very good thing for street driven rides. Depending on block you can get carried away and edge near disaster with some longer stroke set-ups especially if you wind 'em up too high. But the reality is very few guys do more than an occasional burnout or some quick green light go pedal stomps.
Torque is what you feel and makes your car jump off the line. That's what 95% of guys want when they do a bit of spirited driving. When was the last time those of you with a 11 or 12 second capable car actually drove it to that extent? The full quarter run? On the street it just doesn't happen. So if you're not planning to ACTUALLY drag race a car at the track, go ahead and build the stroker engine and have a blast.
And by the way, a well designed and built stroker engine can still wind up to 6k without worry.
 
Thanks. I have had my 67 on the track several times. It is already traction limited! With the TKO it will be worse unless i have the discipline to launch at low rpms. But yeah, that torque is a great feeling!!! The 429/460 block can take a 4.5" stroke with no mods and have a pretty beefy block. Not like the small block Ford that can break a block in half over 500hp. Cast crank and stock block 385 series can handle well over 700hp. So I'm not worried about the strength. I do want to keep it streetable. If it has so much torque I can't drive it without doing a burnout at every traffic light or drive it in the rain then it will be too much. Already I estimate it had around 450hp. I'm keeping the top end stuff, heads, cam, intake, etc. 514 would be plenty. Just as long as I'm not spending a ton of money on it. I will be happy keeping it mild.


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I just looked at Scat's kits again. They have a 4.150" stroke crank kit with .030" over pistons (4.390") that will make a 502. I don't want to over bore it more than I have to so a 502 would be plenty. Kit sells for about $1400 thru Summit with dished forged pistons, I-beam forged rods with ARP bolts and cast crank. Includes rings and bearings too. That would give me 10.1:1 CR with my heads so I could still run pump gas.
 
if you really want some cubes, then cut loose and get a aftermarket 460 block from dart. those blocks can go out to something like 4.65 bore, and with the rigtt crank can push the cubes to 707ci!! john kaase built a few of those making over 1000hp(at the time his dyno would only read 950hp, and hen he ran the engines on his dyno the needle was pegged above 3000rpm and stayed there until the rpms went to around 7000 as i recall, it has been a while since i read about that build)
 
Craig, I will preface with I have no exacting knowledge about stroking a 429 but the education I put myself through when researching a SBF, in general, should be useful. The big danger (aside from H.P. limitations of the SBF block) are all about piston stability. To gain longer stroke, shorter skirt pistons can/are required which can affect piston travel and rod angle characteristics. Some piston designs move the pin location as well that can affect the ring performance and oiling, etc. Not sure how similar issues might occur in your BB. Bottom line being the old adage "no substitute for cubes" holds true. Without crossing the line into "iffy" engine dynamics, bore and stroke it all you can if maximizing power is the goal. More cubes allows less need to push the limits on things like cam profile, etc. which can make for a very reliable and well mannered yet beast of an engine.
 
thanks Terry.
I have been researching a bit thinking about such things as rod length and piston skirts and pin location. Even with the long 4.5" stroke the BBF has enough cylinder wall to avoid using a short skirt on the piston. Pin locations do vary for rod length options but again none compromise the oil rings like I've read about on extreme SBF pistons. The BBF was seemingly designed to be stroked more. The 2 bolt main blocks even have thick web castings for strength. My cam is not the wildest for a BBF but has an advertised 294/312 or 242/257 @.050" duration with .531/515" inch lift. Plenty for a small block and might be a little tame for 500+ cubes. Advertised rpm range is 2500 - 6400 rpm. In the 429 it sounded pretty mean and I revved it to 6K with no worries. I'm not looking for a gazillion dollar engine build making 1000+ HP or even really need to do the stroker crank as I was pretty happy with the 429. But I'm looking at grinding the 429 crank and buying pistons no matter what. The whole mess will need to be balanced too. So for maybe a grande I could rebuild the short block "stock" with a .030" over bore. For a bit more than twice that I can have close to 100 more cubes or more. I don't even know how much more power and torque but I'm guessing I will easily surpass 500HP and 500ft/lbs. naturally aspirated and as you said still be a fairly mild engine. It's probably no more logical to build a stroker than to choose to keep the big block over a 5.0 but now is the time to do it.
 
I think you're being very conservative on possible engine power. 1.25 h.p. per cube is a strong but not crazy engine. I've always target that ratio on the high end for every performance engine I have built. To put that into perspective, that's about a 375 max h.p. built .030 302 (306). There are plenty of those around laying waste to tires every day. Good heads with a port matched intake, correctly ground cam, well tuned carb, hot ignition and a free flowing exhaust gets you there. Would seem to me 600 would be more than a very attainable number with a stroked BB. With the extra weight of that beast you need those ponies to match up with a similar weighted car sporting something like the SB stroker I just built. Go big or go home as they say!

I do agree it seems only logical to spend just a bit more given what those dollars will deliver. Its very cheap h.p. for sure. If not now, will you ever really do it? That's the thinking that got me to build mine. I've always said once my car is done, it is DONE. Nothing to do but drive. Since I missed the cruise again this year seemed the thing to do.
 
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