Well, a late model 350 4 bolt is mine. It's a factory roller motor that's been fully prepped and clearanced for a 383 with up to a 6" rod! I'm very excited. I don't even have a car yet, but I'm on my way to building a mighty mouse.

Just a little info, I plan to build a 550-600hp pump gas 383. Since I'm looking at buying a crank next, is the race light 4340 essential? Can I produce the same power with a stock weight crank? I've seen people talk about how heads make the difference, and I don't plan to go cheap in that department. But I want to be able to turn the 383 up and I want it to turn fast.

I'd really appreciate some input before I spend $1000 on a crank. Do I really need to do this to produce those numbers with reliability....Oh, and I may be living in a dream world, but I plan to make those numbers with a street drivable motor. A motor I can drive to work if I want and go cruising/bruising with on the weekends.

Thanks!

(I'm officially part of the fam now and I'm eager to build the wickedest 383 around my town with your help...)

 

I know your post is in regards to crankshafts, but I can't help but point out that you are probably not going to make 550-600hp and maintain streetabilty without killer heads. Just curious what kind of heads you plan to run.

Anyways, as far as a crank goes the answer is yes, you are going to need a high quality forged crank. It has to be light, because you are going to need to spin this motor pretty good. And it has to be strong, because you will be spinning it fast and putting a lot of power through it. Light+strong = good materials, machining, inspection, etc. = big $$$. $1,000 may not be enough for what you have in mind.

"Reliability" is a relative term. Depends how you plan to use it and how you define reliability. A 550-600hp small block is no time bomb, if good quality parts are used and assembled correctly. But if you regularly use all of the ponies, which is going to entail turning it somewhere in the range of 7,000rpm, don't expect to do this without fairly frequent teardowns for inspection and freshening. And even with that, it's not going to last for 100,000 miles or anything like it.

I never understood the rational for planning a buildup based on a certain hp number. The exception would be for racing in a class where you know how much hp you need to be competitive. It makes more sense to define a budget and try to get the most performance you can within that budget while maintaining the other characteristics you want (drivability, reliability, etc.).

Good luck.

Rich Krause

 

Rich, you're right about planning a budget and getting the most out of it. I say 550-600 because that is what I assume is needed to make a 3200 lb 1st Gen run 10s with the proper traction. 550 at the fly would be around 460 to the wheels...If a 383 in a 1st gen won't run 10s N/A on pump gas then by all means tell me now!

A friend bought a Probe lightweight forged crank for around $900. I figured that would be a good crank...then I'm sure I'd need a light rod/piston which equals more money...

I had planned on a set of AFR 227s at the least. I've read where the GM Performance heads are making sick power. I'm no where near ready to buy a set of heads so I was going to focus on the bottom end first. As far as a cam goes I was going to put a hydraulic roller in it...

Thanks for the input Rich. Let me know where I need to go with this....

 

Hey fickle, I will tell you my opinion from my own experience. I had an 10.8:1, N/A, 383 with Brodix trac 1 heads flowing 295@600, with a victor jr intake. The cam was a comp hyd roller 242/248 575/599 on a 110. The motor made 517HP @6100 rpm. Those numbers were corrected to sea level coniditions. The real numbers with the shop eleveation were in the high 490's HP.

There are alot of guys out there makin serious HP with 600 dollar cranks (eagle scat, cola) and living a long time. With a motor makin 550-600HP I wouldn't hesitate running a cast steel crank in it if money was tight. For insurance step up to a 4130 or 4340 crank and don't worry about it.

 

A few questions and things I left out. How much does this car weigh? What size slicks will you be using? How much converter are you willing to live with when you drive to work?

If its 3400lbs you will need 550, maybe a little more, to get into the 10's.

I know with the 242/248 cam it wasn't huge but more than I would want to drive around all the time. I know it will be easy to get better heads than what I had and that will help some, but makin a true 550 I would think you would need a bigger cam than what I had or a tad more compression.

 

Great info man! Thank you!

So I guess you were running a 4340 crank huh? I was going to go with a LIGHT 4340 if it was necessary to make that much power. But, 490s is PLENTY for me. Was that power you made to the wheels?

I haven't bought the car yet. I was going for a 1st Gen Camaro. As far as converter, I'd say nothing over 4,000. I'd love to run a 5,000 converter with a glide and transbrake, but that wouldn't be fun to cruise around in with the wife. This motor I'm building is already going to scare the crap out of her....

As far as heads, I was figuring anything that flows over 300 would be fine. And I don't mind a huge cam. I love that radical sound, just so long as the motor doesn't run too hot. I'll spend the money to keep it cool (big radiator, electric pump and electric fans).

Tires I haven't thought about yet. I plan to have 2 sets of rims/tires. A 17" set with BF Drags if I want to go "touring" and a set of ET Streets and front runners if I want to go hurt some feelings.

How fast was your car with the 383?

 

I had a 4130 crank and its the sameone im using in my 1000HP turbo motor project that I will hopefully get finished one day =). That power was at the crank.

The reason I asked about the converter was I had a 400 w/brake and a pretty tight Neal Chance converter, 3400 on the brake. I ran 7.42 @ 92 MPH in the 1/8th, never ran 1/4. Comparing the MPH with other cars at the track I had the same MPH but was about 3-4 tenths slower in ET. That told me the power was there but I wasn't getting off the line because of the converter. I know I wasn't spinning or anything like that. The reason im saying all of this is because according to a chart I have it takes a 7.00 to get into the 10.90's so i would have been pretty close with a different 4500 converter I think. This was at a little over 3500lbs w/ driver and a 3.90 gear.

You have email as well

 

Does anyone know what a light 4340 should weigh? I've seen them vary from 44-50 lbs....

A friend has a Scat that weighs 44. It looks great. Would this be a good crank to go with?

 

I like Scat's stuff. As far as that particular crank being suitable for your application, what is the pn? I will look at their catalog and try to help. You might want to call them and ask though. A friend got one of Scats complete rotating assy's. Paid <$2K for a 4340 "superlight" crank, 4340 rods, and SRP pistons. worked great for him.

Rich Krause

 

There is a couple of things you can do here. A $1000 crank on a street motor doesn't really make sense, a competition motor it does though.

If this is going to be a street motor that doesn't see really high RPM then a Scat 9000 series crank with some good strong parts above it will hold 600hp and 7000rpm.

Scat now has a Lightweight 383 9000 series crank, which would work awesome. Throw on a set of their 4340 Forged I beam 7/16 Bolt polished beam rods. Those are some very nice parts for a street motor. The only other thing you need is some lightweight pistons just to keep the rod and crank stresses down. If you are running a 6.0" rod there are alot of decent pistons in the 380-410g range that will work really well here.

On the other hand, I have run the Scat Ultralightweight cranks. Those are some nice parts and are very strong. You really can't outpower them on a street motor anyways.

For example, the Engine Master motor we built last year was a 560hp 365 cube SBC, with 530 ft lbs of TQ. That used a Scat 4340 Ultra Light Crank, and some nice light pistons and Eagle H beam rods. That motor was ment to be flogged on a Dyno which is about the hardest work a motor will see. Going to a 383 and more cam, since we only ran a 214/224 cam to get those numbers you could easily make 550-600hp if you do it right.

We used these heads on that motor http://www.weldtech.com/graphics/BrodixTrack1Chevy.gif
I actually saw more flow than that on our bench, but if that small of a cam can make that kind of HP with them a little bigger cam would have easily but down 600hp.

I would bet that with good heads, a solid flat tappet cam, and that 383 bottom end I spoke of above you could out do your buddy's motor with the $900 crank.

On a 383 you don't need to spin that motor more than 6500, and you just need some decent 210-225cc heads to do it. I would personally go with a 210cc AFR Race Ready head and touch them up some to bring up the midlift numbers, that will definately get you some big power numbers.

Going back to the main topic. Cranks. I have seen guys spend way to much money on Forged bottom ends just to end up putting junk heads on top and making much less power than they expected or should have with that budget. That's why I mention that Scat 9000 crank and I beam Rods. When money is tight (it almost always is) like a claimer engine class, those parts are a great way to save money. They are even cheaper to run than stock unit because everything is done and ready to go. I plan on dropping one in a 700hp N2O motor for a claimer engine drag class and not worrying about it at all.


Bret

 

Less than 2k for an entire assembly sounds great! What kind of power was he making?

 

Bret:

Thank you so much for all the info. I plan to use a hyd or solid roller cam and a great set of heads. I think my hp goal can be achieved...


By the way, I picked up the block today and it's gorgeous. I'll post some pictures soon....

 

~800hp on an engine dyno. It's a race motor. Probably overkill on a street motor as Bret suggests, but not a whole lot more expensive than the mid-grade stuff. I dunno, but I just like that nice forged stuff.

Rich Krause

 

Was that motor N/A?

Rich, I know this question is off topic but where can I find 3/8" 14 thread count bolts for my block to mount to my engine stand? My builder told me it was a 14 thread count...Home Depot didn't have a 14...so my block is sitting until I can get the right bolts to mount it with....

 

Yes, it's NA. But definitely not a street motor.

I get fasteners and that sort of stuff at my local NAPA. If they don't have what I need, there's a big industrial supply house, but they prefer not to sell less than 100 units, so I try not to bother them unless they are the last resort.

Rich Krause