I would like to get close to 600hp N/A from a 383, what rotating assembly do you guys reccomend? Can I use a cast crank?

At a 600HP smallblock you have past the land of safe cast crank use.
I would be looking to Crower for the rotating assy on that one. The Scat Forged stuff will hold up, but for the quality of the Crower stuff is much higher and its MUCH lighter

Callies also has some decent cranks for that power level, however I usually use Scat.

Eagle stuff has really taken a big step up in quality in the last few years, at least that is what several different engine builders have told me.

Now if you were on the dark side we would not be having this conversation :)

Anything but Scat according to Brian at Syracuse Crank. He charges extra to work on their crap. He prefers Crower as they have top quality stuff.

Eagle stuff has really taken a big step up in quality in the last few years, at least that is what several different engine builders have told me.

Now if you were on the dark side we would not be having this conversation :)

LMAO, I'm glad there is a couple of die hards over there on the dark side. It keeps things fun. But I'm not so sure I would want to be lumped in a group with the likes of Bob and Wayne ;) :) ;) sheeeze, that's gutsy!

I do hope Eagle has gotten their act together. They make a pretty decent product. The forging is OK,, the final finish and sizing is all I can complain about. Buying a used Eagle crank that needed grinding might be a good bargin. A good shop could mag, cut it 10/10, nitride it and straighten it for around $250 - $300 If you bought it right, that might be a VERY cost effective high quality crank.

Mike there are plenty of guys making 600 n/a in small blocks with stock cast cranks. How long it lives,,,,that's another question. And there are too many variables such as internal / external balance, reciprocating weight, rpm range, to say what 'should' and 'would not' survive. IMO external balance, cast crank 383's should not be on the track spinning 6500+ or making anywhere near 600HP. But that's an opinion.

well I dont want to take chances on this motor if I need a $2,000+ rotating assembly than thats what I'll get. I want piece of mind when Im 2hrs away tuning 7,000+.

I guess I would do this the other way!!

Use a 400 block and a stock forged 350 crank, good rods and needed pistons and come up with a 377.5" engine that will rpm fine for me..

Plus, run better heads b/c the bigger bore will allow it to suck better up top b/c of less valve/chamber/cylinder shrouding..

It may not make quite as much torque, but I bet it will out hp the longer stroked/smaller bore engine up top..

pdq67

LMAO, I'm glad there is a couple of die hards over there on the dark side. It keeps things fun. But I'm not so sure I would want to be lumped in a group with the likes of Bob and Wayne ;) :) ;) sheeeze, that's gutsy!
Marv You almost made me laugh the tea I was drinking out of my nose.

Im not against the little block especially with a procharger on it, but I guess as a teen I always couldn't afford the big block and loved the sound and power. Heck the little blocks couldn't hold a candle to them back then. I call what I am building a big block (496) but in this day and age that is a small big block.
I do hope Eagle has gotten their act together. They make a pretty decent product. The forging is OK,, the final finish and sizing is all I can complain about. Buying a used Eagle crank that needed grinding might be a good bargin. A good shop could mag, cut it 10/10, nitride it and straighten it for around $250 - $300 If you bought it right, that might be a VERY cost effective high quality crank.
I actually heard the same about scat that in the last few years their stuff had to be checked and sometimes turned, thats new stuff.
The Eagle stuff has been coming out good to go.

May want to take a look at Ohio Crank, good ole USA company. Their prices are very competative.
As for quality, I have heard of lots of peeps using them, I will know in about a week when it arrives at the machine shop. Customer service is good if you talk to Stan Ray.
(caution short rant)
When I ordered my stuff I was under the impression that the motor was .60 over and whent with a .70 piston (special order). Well the machine shop called me yesterday asking "hey why do you want to go .70"? I told him that it was his partners suggestion for a fresh bore. He told me that the block is only .30 over. Anyway, I called Ohio crank and talked to a guy that was a crank. I told him that I need to change it to the.60 piston and he was like "cant you just bore it out" I said "yea, but I am not going to do that". He changed the order that never even got shipped yet but was kinda rude about it saying " I guess I'll send back the pistons we special ordered for you". I was thinking thats great I guess I'll go ahead and buy the $1,800.00 rotating assembly from you then.

I will try and revisit this post later on but DO NOT use a cast steel at this level (we have 3 Scat 9000 series cranks that failed at the front rod pin) and at 600 HP my cast GM 400 crank had cracks in the fillet area on the bottoms of the pins after one season, 6800 max, was internally balanced too. Good news though, I should be able to salvage most of the mallory for another crank down the road. :rolleyes:

To be continued....

well it definately sounds like Im going forged, what the heck is the difference 51xx, 4130, 4xxx, 5xxx what is better? what is best for a mostly street but occasional (once a month) track car?

4340 is a forged steel crank... that is the one you want.

M,

Check Scat's site b/c they have a very good write-up on what you just asked about.

Easy reading..

There's like Nodular/Ductile-Cast Iron, Cast-9000 steel, forged 1053 steel, 51zz, 4130, etc., etc. and finally the forged 4340 steel that is hard as well as tough as nails..

pdq67

my 2cents
all things being equal, a 377 will not make more hp than a 400 will. not that a 377 is a bad motor. the 400 will make the better torque AND hp. and you can really feel the torque .

dj

Even though we are a relatively small shop (compared to the likes of Shaffiroff, Musi, etc) we have used/sold an amazing quantity of Scat product over the past 5 years and I'm happy to say that the quality is excellent, and the features you get for the money are second to none. Yes there are some amazing cranks out there, but are priced accordingly and aren't a logical choice for the bulk of us and our power expectations. We've sold Scat cranks from the basic cast iron up to a custom billet stroker crank for a 385 series Ford that runs a 14/71 blower and injection on top. Pick the correct crank for the job and you won't be broke or dissapointed. We have learned that the 9000 series, although the tech we spoke to at Scat felt that it was a suitable choice, has no place in a high compression dirt sprint car application. (the ones that broke at the front rod pin) We built identical 565's last winter, one used a Scat Pro Comp lightweight crank, the other a Lunati crank. The weight difference was better than 15 pounds with Scat being the lighter one. I don't recall the Lunati being drilled in the rod pins, but it was fully counterweighted and had gun drilled mains. It spent a few hours on the lathe reducing the counterweights to bring it into balance. The Scat crank needed a slug of mallory in each end to balance it. Sizing on both cranks was comparable as well as finish. Balancing costs were similar between the 2, trading mallory for time on the lathe. Being fully counterweighted the Lunati should last longer, but I don't expect lifespan will be an issue with either one at there current output. (around 920 hp) The Lunati crank was approximately 1.5X the cost of the Scat crank.
In catalogues past Scat lists all their forged cranks above their standard weight cranks as being manufactured in the USA. Of the few midrange "Pro Comp" cranks we've used, there isn't a square inch on the crank that hasn't been massaged and machined into a nice looking piece, and the Superlight crank I ordered for myself is a work of art with the pendulum undercut counterweights and aero-wing counterweight profiling. We've used a few of their standard weight steel cranks, and the journal sizing/shaping isn't quite as good (perhaps due to the offshore machining) but are still well into factory tolerence. All the rod pins are drilled, which is machining you have to pay extra for from the higher end companies. The worst balance job I've had with a Scat steel crank is it needing a slug of mallory in each end, which is nothing really when the end result is a lighter crankshaft. If you build a 3.75 stroke small block with the Pro Comp crank you'll need 1 3/4" slug in the rear counterweight due to them machining the flywheel flange into a star shaped flange. If you use the Superlight crank like mine you'll need a 1" slug in the rear, and a 3/4" slug in the front to balance it. These are all based on H beam rods (6") and reasonable weight pistons. If you use flyweight stuff, you may not need any mallory, if you use big portly rods and bricks for pistons, expect to need a bunch of mallory.
For the value, I feel it's extremely tough to beat Scat products.

Mwilson, for what you are looking for, consider Scat's 4-350-3750-6000-2 crank (it's 49 pounds) and Scat's 2-350-6000-2100 H beam rods. You won't be disappointed.

Crank:
http://store.summitracing.com/partdetail.asp?part=SCA%2D435050%2D2&autoview=sku
Rods:
http://store.summitracing.com/partdetail.asp?part=SCA%2D6600021&autoview=sku
Same parts, just with new part numbers.

so rust, what is the compression, HP and RPM limits of the Scat 9000 pro comp lightweight crank for a 383 with 5.7 rods

Keep in mind the only place we have failed the 9000 series cranks is in the dirt sprint cars. These were alky carb'd 23° engines with between 12 and 14.5:1 compression, turning under 7000 RPM. Yes the car was the fastest on the track, but it's of little value if you can't get the parts to live for a couple of seasons. The customer wanted to save the money on a forged crank(s) at the time but has since had us rebuild the shortblocks with the Scat forged cranks. The other things that were failing is the main caps and on one 400 block the entire bottom of the crankcase, webbing and all, split out from underneath. Another broke # 2 and 3 main cap. (2 bolt 400 block with studs) The 14.5:1 is getting a lightweight steel crank and is going into a 509 block with steel splayed caps and a half fill of rocktite in the cooling passages, the low compression is getting a standard weight steel crank and I converted that 817 casting block (that had the broken main caps) to a 4 bolt using GM nodular iron caps. This will also be the end of us using domed pistons in 400's in an oval track setup, the factory block just isn't capable of taking the horsepower these engines make. (not the high end outlaw cars, this is a IMCA claim rule class)

The tech said about 500 HP. With a quality dampner I wouldn't be concerned about 7000 peak RPM in a street/strip setup where it doesn't see a lot of time up there. As far as compression, detonation is the killer of the crank here, so don't use any more than what the intended gasoline can handle.
I think for a street car it is a good value, esp. if you step up to the 6" rod setup and internal balanced crank. Looking at it another way, buy as much crank as needed to stay at the current value of the engine. (don't waste your money on a billet crank for your stock engine, and don't use a stock crank in a 2500 HP blown alky setup)

I have an Eagle forged rotating assembly and it is holding up great all the way to 6700. I agree that Eagle has increase the quality of there product in the last few years. I sell the full line of Eagle products for a great price, so if anyone would like a price on something I would be glad to help.

I'll agress with Rust; Cast crank limits are ~ 500HP and 7000RPM

If $$ is not an issue - 4340 is the stuff you want.