Cast Cranks - How Much HP & RPM?

[blykins]

How much hp and rpm will a cast FE crank take? Is it good for 550hp and 6500 revs?

[bmcmillan]

I'm not the final source on this, but I have never heard of a steel (not iron) crank ever breaking. At any RPM or HP.

Brian

[blykins]

Well, steel FE cranks are a little hard to come by these days.....unless you wanna buy a $1000 billet piece from Scat.....or stumble upon a 427 steel crank.....that's why I was asking about cast cranks.

[MidOHasp]

I don't know about for FE's, but is there not such a thing as a "Cast Steel" crank? I was under the impression there are 4 general types of cranks out there, leaving out anything completely whacked..

Cast Iron
Cast Steel
Forged Steel
Billet Steel

I am still looking for a 7" stroke, billet unobtanium crank for my 351W.

Brent, I know the 351C NASCAR motors ran 650+ HP on a cast crank, don't know if it was steel or iron. I'd imagine with 75 more cubes or so, you'd be able to pump out 550+ HP.

As far as 6500 RPMs goes, that doesn't seem like enough RPM to make a cast crank come apart.

But I am using words like "seem" and "imagine" so go figure.

[ItBites]

Blykins,

If you want to run a cast crank, the key is to have a perfectly straight, true, set of journals in the block (read align bore and hone). If you do this, you will get the most out of a cast setup.

I'm no Ford guy, but I can tell you that if it were a BBC, I'd feel better if revs were limited to 6000 on a long-stroke, cast crank. 550 hp, no problem.

[blykins]

Just tossing around some build ideas.

JP....just cast iron, forged steel, and billet steel for the FE's.

New cranks from Scat (to the best of my knowledge) are either cast iron or billet steel I think.

I've found new Scat cast cranks that are already balanced in several different strokes for about $580. I called Scat about a billet piece a couple of years ago.....pretty sure it was close to $2000.

I've also found some vintage cast pieces that have been ground, chamfered and micro polished for about $150. Most of them are 10/10....but I don't see where that would hurt anything.

I can't afford the $2000 crank.....not that I would ever need one.....and it makes more sense to me to pay $150 for a crank ready to go than it does to pay $580 for one.

I just know what I would like to get out of my FE performance wise....just making sure the parts will support it.

Planning on H-Beam rods.....forged pistons....solid flat tappet cam.

If I go with the vintage crank, it's a 3.78" stroke. With a 4.130" bore, that would give me a 406.

I know I could get 550hp out of a 408 Windsor.....just don't think I can squeeze it out of an FE though.

Any suggestions?

[MidOHasp]

You mentioned forged steel, but didnt mention if, and from whom, they are available.

IMHO, and I'm not currently trying to do a budget FE build (or any build for that matter), the $430 for a new cast iron crank from a reputable place like SCAT might be money well spent. Although %age wise, that depends on what your total budget is...

I wouldn't attach H-Beam rods and Forged Pistons, by the way, to a 40-year old cast iron crank. Just doesn't make sense. Chain's as strong as its weakest link.

At that rate, put in some good upper-mid-grade I-Beams and some "good" pistons and just see what you can do with it and have some fun.

550HP is gonna be a stretch, man...you're going to have to do it with RPM, compression, etc... on a solid flat tappet cam like that.

[jdean]

For the 460, which has a very heavy cast crank, there are people using the stock cast crank to make upwards of 1,000 HP at 8,000 RPM.

It apparently, and surprisingly, holds up well to this type of abuse.

[blykins]

You can get a forged steel crank two ways JP....one is by using a 427 piece....or you can turn an FT truck crank's snout down and use it. However, I don't think the truck cranks are crossdrilled.

I don't know how much technology has advanced in 40 years....but I would think it would be the same as attaching H-Beam'ers and forged pistons to a new Scat crank. Sure, the Scat crank is brand new...but it's still cast.

I'm curious now to find out what would be different between new cast cranks and cranks of yesteryear....porosity? Heat treating?

[1962SuperStock]

Keith Craft (advertiser on this forum) sells 550 hp, pump-gas 390 crate motors with cast Scat cranks (416-445ci), H-beam rods and CNC-ported Edelbrock heads for $9,000. Doesn't need to rev past 6,000 or so.

[Steve R]

As A kid I "Bricked" the gas pedal of a 1966 Galixie 500 with a 390 for 45 minutes. We got bored waiting for it to blow up so we removed the brick. it promptly came right back down to a nice idle.
(Cast crank)

[Rick Parker]

Blykins:

From years past the cast cranks were 'Made in the USA"
Now they are Made in China............................from shredded Buicks.

[blykins]

Thanks for the info guys.....

[Rory428]

In my 428 powered Fairmont drag car (bracket racer), I`ve been running a stock 428 1U crank for 10 years now, with zero problems. It`s a 4 speed, and I dump the clutch between 6200-6600 RPM, shift at 6200, and hit 6500-6600 at the finish line. This engine has never been on a dyno, but according to my trusty Power/Speed calculator, it should be around 550 HP. I recently had to junk the block, as it split the #2 &4 main webs, but the crank looks ready for more! I have raced FE`s for almost 30 years now, and the only crank failure I had was years ago with a 390 on nitrous oxide. This engine was also in my Fairmont, and ran similar numbers (10.2 Et @ 132 mph) with a C6, and after a couple of years, the block had ALL the main webbing rip out between the cam & crank, which broke the crank in 5 seperate pieces. But other than that, the stock cast cranks have held up very well for me. In fact, other than splitting a couple of cylinder walls on 428`s, the one split main web on the 428, plus a couple of broken OE rods, the FE has been pretty darn reliable for me.

[bret a ewing]

If you are putting the cast crank in a cobra, you will not generate enough traction to break a cast crank (even 600 # torque).
According to scat, they have never had a failure below 700#'s torque on a street application.

[Barry_R]

I've a fair amount of cast crank experience - all of it positive. My 452 and 439 inch engines had CJ cranks and pushed my 3600 pound Torino to anywhere from 10.90 to 11.20 without the nitrous - and 10.20 to 10.70 with it. Literally thousands of passes over a 15 year period. I sold both ranks unbroken last year.

My current 505 incher has a Scat cast piece has many, many dyno pulls and a full season so far, and has exceeded 700 HP on the pump without incident.