[HWYSTR455]

Yeah, I'm not sure that's apples to apples with your 455 failure situation, and don't believe it supports the claim of studs and aftermarket caps not worth it.

Let me guess, you used a 455 block, 2 bolt mains, cast OE crank, OE bolts, and loaded with slicks and numerous passes. And the main downs were found in pan. Hm.

OE cranks turn into a wet noodle at RPM, and the caps were never designed to handle max effort use. I think many racers/builders after 600hp know to use forged cranks, 4 bolts caps at least, prefer aftermarket, and they stud the mains & heads. It's SOP.

I think many also recommend lifter bore braces after X lift/X spring pressures too, again SOP.

Max effort racers also recommend at least half fill the blocks too.

Considering the above, I'm not surprised you had issues with the 455. You tried to make it do more with less and paid the price.

So, not apple to apple comparison, and doesn't support using OE bolts over studs. No seasoned racer in their' right mind would use OE caps and OE bolts in the scenario put out there.

Same with cast OE cranks. I don't care what the core looked like or if was a granny-car with just grocery trips, everyone knows a forged cranks is better. And they aren't 40+ years old either.

People come here to real-world advice and help, and wow, there is no spin-control sometimes. People sometimes walk away more confused that anything.


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[Gach]

Making 700+ hp in a stock block at 6500-7000 k.. doing Constant quarter mile runs, is like running around with grenade with the pin out. I don’t care what you do to it, lifter bore brace 4 bolt steel main caps… steel crank, lightest rotating assembly. have people done it sure and they’ll live for a while. you can spend the money and push the envelope with the stock block but it’s like going to casino after you’ve lost a few grand…do you feel lucky today. Any one that encourages it should be lock up.

[PunchT37]

The op is looking for a 550’ish hp street motor not a full blown race motor. I think he’s good with what he’s got adding good rods and pistons.

He even has overdrive.

[Gach]

Originally Posted by PunchT37

The op is looking for a 550’ish hp street motor not a full blown race motor. I think he’s good with what he’s got adding good rods and pistons.

He even has overdrive.

Exactly agree

[HWYSTR455]

I think the general consensus is that the line in the sand is 800, but by taking the additional steps extends that window of 'live for a while'.

If you do 80% street and 20% track, that window increases more.

That 'window' actually has a name, it's called Meantime Between Failure by the way.

You start with questionable parts, that window decreases. And you can't tell me a 40+ year old crank has no risk, and will last as long as a brand new OE crank, not to mention even a brand new cast crank.

If you have to replace pistons, rods, AND have the crank done, it is less expensive to buy a stroker kit. So why wouldn't you?

Ok, even though it's a 'street' engine, taking nominal extra steps to make it last longer (in any condition/use), for a reasonable cost, doesn't make sense?

Or even in a full race situation, not taking ANY steps to make it last longer, makes sense? Because it's just in the end going to fail anyway?

You want an engine that you don't have to worry about in a street/strip car and last a long time? Take the extra steps to increase the failure window.

If you don't have the money to do it all, then just look at the amount of cost in comparison to the risk and choose your direction. But you have to keep in mind those areas you skimped, and act accordingly.

Studs work. Forged cranks are better (and sometimes cheaper). Aftermarket mains caps are stronger than OE. Write out the cost of each and make your decision.

It's as simple as that. Arguing that OE bolts are better than studs is non-productive. Same with 4-bolt mains, aftermarket caps, or forged cranks. Everyone with common sense already knows the answer.


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[PunchT37]

Originally Posted by HWYSTR455

I think the general consensus is that the line in the sand is 800, but by taking the additional steps extends that window of 'live for a while'.

If you do 80% street and 20% track, that window increases more.

That 'window' actually has a name, it's called Meantime Between Failure by the way.

You start with questionable parts, that window decreases. And you can't tell me a 40+ year old crank has no risk, and will last as long as a brand new OE crank, not to mention even a brand new cast crank.

If you have to replace pistons, rods, AND have the crank done, it is less expensive to buy a stroker kit. So why wouldn't you?

Ok, even though it's a 'street' engine, taking nominal extra steps to make it last longer (in any condition/use), for a reasonable cost, doesn't make sense?

Or even in a full race situation, not taking ANY steps to make it last longer, makes sense? Because it's just in the end going to fail anyway?

You want an engine that you don't have to worry about in a street/strip car and last a long time? Take the extra steps to increase the failure window.

If you don't have the money to do it all, then just look at the amount of cost in comparison to the risk and choose your direction. But you have to keep in mind those areas you skimped, and act accordingly.

Studs work. Forged cranks are better (and sometimes cheaper). Aftermarket mains caps are stronger than OE. Write out the cost of each and make your decision.

It's as simple as that. Arguing that OE bolts are better than studs is non-productive. Same with 4-bolt mains, aftermarket caps, or forged cranks. Everyone with common sense already knows the answer.


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I can agree. But, would one put a nice forged crank in a 557 block?

[Steve C.]

Not any endorsement, just a tid bit to share with my higher rpm experience...

My 450cid combo made 699.9 hp at 6900/7000 rpm.
During its life it encountered damage to the Crower billet 4.125" stroke crank, a crack which was repaired and returned to service.
Also some associated bearing damage. But the block survived, which I later sold.

That power level was with a Victor/1050 Dominator set-up.
However at the track it used 4150 carb (684hp) and on occasions limited street use.
The Edelbrock heads had 11.2:1 compression.

1970 400 block / 9799914
Filled to freeze plugs with Race Engineering "Block Rock" material
Five Pro-Gram Engineering main caps installed:
Billet steel front main cap
Billet steel 4-bolt center main caps / fitted with oversize dowels
Billet steel rear main cap
ARP stud kit used and block align honed
Bored and honed with a torque plate / 4.165 bore
Block was properly squared up relative to the corrected centerline of the crankshaft.
Mega Brace lifter bore bracing installed.


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[grivera]

Originally Posted by PunchT37

I can agree. But, would one put a nice forged crank in a 557 block?

That’s funny - a forged crankshaft in a 557 block is like a tie on a pig. Those blocks should only be used in stock <400 hp type builds and not a performance build. Sure it’s possible the block will survive but is it probable?

[PunchT37]

Originally Posted by grivera

That’s funny - a forged crankshaft in a 557 block is like a tie on a pig. Those blocks should only be used in stock <400 hp type builds and not a performance build. Sure it’s possible the block will survive but is it probable?

That was an extreme example of my point all along.

[grivera]

Originally Posted by PunchT37

That was an extreme example of my point all along.

Haha - I figured as much!

[Tim Corcoran]

I believe using studs on the main caps is a pretty good upgrade even if using a factory cast crank. First off with studs you're not twisting on the threads in the block while torquing up the studs, as the bolts torquing thru the threads in the block does cause additional stress to the block. Secondly studs use fine threads on the outer side of the studs and nuts. The fine threads for an equal torque application compared to course threads will give you more clamping force, plus the torque rating of the ARP 8740 or 2000 fastener is higher so you end up with a significant increase of clamping force. This additional clamping force will reduce cap walk and add stability to the crankshaft. This combined with having tight fitting longer than stock dowel pins adds additional stability to your rotating assembly.

[mrennie]

This scenario has "mission creep" all over it. Going to get expensive, faster...

I went through this same agony when I built my motor, I already had a 455 block and 2 factory cranks, and with my intent to use ported KRE heads, RA exhaust manifolds, and the Stump Puller cam, it didn't make sense (to me) to buy a forged crank for 98% street use. However, I did buy forged rods and lighter Ross pistons in an attempt to make everything last. Time will tell!

[tom s]

FYI,I unknowing about 557 block I built a all forged assm some years ago.The build was on this site.Made just under 600 HP and lived on Joe Shermans dyno.Since it has been in a 70 GTO with no issues!Better to be lucky than good!Tom

[tom s]

585 HP with KRE D ports,557 block with a pair of 750s on a Bathtub intake.Build is on this site.Tom

[Johnny406]

Originally Posted by tom s

FYI,I unknowing about 557 block I built a all forged assm some years ago.The build was on this site.Made just under 600 HP and lived on Joe Shermans dyno.Since it has been in a 70 GTO with no issues!Better to be lucky than good!Tom

Back in the mid 90's I found a 557 block in a junkyard in Raton New Mexico. It has a sleeve, stock rods, heavy TRW pistons and has been in two cars to include my race car and the 406 of my screen name, had both nitrous and a centrifugal supercharger on it and it still lives... but I won't push my luck and try/do that again...

[Cliff R]

"Yeah, I'm not sure that's apples to apples with your 455 failure situation, and don't believe it supports the claim of studs and aftermarket caps not worth it."

This particular 455 build started out around 450hp and 12.0's at 112MPH. It was nothing more than a cast crank, cast rod/TRW forged piston deal with home ported #48's on it with a Comp 292 Magnum cam when i got involved

The first upgrade was just having the heads ported and adding forged rods, better pistons, and 260 @ .050" flat solid cam. That pushed the power up and good for high 10 second runs, which it did for many years w/o issue. The next more was to add ported Edelbrock round port heads and solid roller cam, putting it past 600hp and it survived fine there for quite a few years.

The last time it was out a larger solid roller cam was installed and more head work. The heads were professionally ported to 330cfm and cam up near .750" lift and 276 @ .050". The short block was fine far as bearings go but I did find two main cap dowels in the pan and wanted to go aftermarket with the block at this point but the owner wasn't having any of that.

I did talk him into a lifter bore brace but the block just had too many runs on it and 13 runs into the last deal it caved in the lifter bores even with a brace installed and it was all over. Remarkably the crank looked fine depite all the carnaige but I was afraid to use it. The Crower rods looked pretty good depsite munching quite a few of the pistons during the explosion.

We fixed it by replacing it with a KRE block (505cid), Star Galaxy forged crank, another solid roller cam, High Port heads and came off the dyno at 750hp. That engine still resides in the car and only apart once for rod bearings, rocker arms (cracked most of the Scorpion full rollers) and a new set of PAC springs.

So no more running around with a hand grenade with the pin pulled out.....FWIW......

[HWYSTR455]

Originally Posted by PunchT37

I can agree. But, would one put a nice forged crank in a 557 block?

This thread is based on a 455 block, but no, you wouldn't put a forged crank in a 557 block, you just wouldn't start with a 557 block.

I'm not getting what the point was supposed to be.

But one point of spin control I was trying to make is being proven in this thread.

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[PAUL K]

https://forums.maxperformanceinc.com...errerid=134156

[HWYSTR455]

Good discussion. Just to say, I must be one of those 'fingers' on the hand counting broke ones.

Couple take-aways from that thread:

"I have had a couple check cracked after being in service a while. In my opinion they are very durable but are still a cast part with about no radius"

"It seems like it is fatigue life that breaks them with a mix of street driving and racing more often than big HP racing. It is hard to catch them before they fail because they do not start small cracks that you can inspect or mag, they hit the fatigue limit and just completely let go "

"A street or street/strip crank isn't going to be removed and inspected on a regular basis like a race crank. A cast crank would be more likely to suffer a catastrophic failure than a forged one due to material and production process."

"Cast iron is very strong but somewhat brittle.
Brittle material is very susceptible to stress concentrations in corners...big fillets are a huge benefit!
Brittle material is very susceptible to impact loads.....aluminum rods add some important cushioning effect."

"IMO, once you exceed factory stress levels and usage models (load, rpm, time) you are rolling the dice."

"Jim Hand had a lot of passes and street driving on the one he broke, most of the time it was running 13s to low 12s in his wagon."

There's more, but I rest my case.

As a note, mine broke in front of #2 journal, and believe it was due to a balancer. I know the pulleys I used were old, and didn't run 100% true, but not sure that added to the failure or not.

I ran new pulleys after that tho.


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[HWYSTR455]

Yes, it was an SFI balancer.


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