[dmccoy72]

I am currently doing a complete rebuild on my 72 Chevelle. I recently rebuilt my 350 engine, had it bored .30 over and replaced everything with performance parts except for the rods and crank since they were in good condition. The new motor has about 50 miles on it but since it is out again for the complete rebuild (body work) I was wanting to put in a 383 crank.

I was looking at two on EBAY:
The first is an Eagle ESP
http://cgi.ebay.com/ebaymotors/ws/e...RK:MEWA:IT&viewitem=&item=230113184876&rd=1,1
The second is a Scat 9000 Pro Comp
http://cgi.ebay.com/ebaymotors/ws/e...RK:MEWA:IT&viewitem=&item=180104456691&rd=1,1

What do you guys think? An engine shop will balance it for $250, is that a decent price?

 

[72Chevellekid]

I've heard good things about Scat cranks, my friend has that crank for his 71 nova. But in general i really don't know much about cranks, so i cant tell you which one is better based on technicality.


Ryan

 

[BillsCamino]

Scat! But you should be able to find one that will Internal balance. :thumbsup:
This way you can reuse your existing damper and flex plate/flywheel.

 

[Tom Mobley]

if he finds an internal balance one he'll have to change rods and pistons. cheaper to buy the flexplate and balancer.

Here's a deal: if you round up a set of stock 400 5.565 rods you can run your existing pistons. set of good bolts, resized, they're ok for hot street use.

 

[dmccoy72]

Cool! I will look for a set of those 400 5.565 rods. As far as the price of the two cranks I am looking at, does anyone have any more input or comments about the two brands? I have heard good things about both and the Eagle ESP is less expensive, but if the Scat is a lot better I would have no problem spending the extra 50-75 bucks!

 

[Aaron]

I'm curious about this as well.

I plan on using a Scat or Eagle crank, Eagle SIR rods, and Probe pistons.

Stroking a zz4.

 

[bigjimzlll]

I used a cast eagle 3.75 crank once. I did abuse it with some 150 shots of N20. It had hundreds of micro cracks in it. I also have used a 3.75 400sbc 4340 crank. It still is running strong and has been severly abused.

 

[Aaron]

Do you think you would of put cracks in it if you did not spray it.

 

[bigjimzlll]

don't know....All I know if I had to run a cast crank, it would be a Scat...for a couple of bucks more I'd feel better.

 

[dmccoy72]

if he finds an internal balance one he'll have to change rods and pistons. cheaper to buy the flexplate and balancer.

Here's a deal: if you round up a set of stock 400 5.565 rods you can run your existing pistons. set of good bolts, resized, they're ok for hot street use.

Does this mean that if I buy an internally balanced crank and get the 5.565 rods I will not have to change my pistons or buy a new flexplate and balancer?

 

[dmccoy72]

Bigjimzll...why do you say that?

 

[RB69SS396Conv]

You can't internally balance a motor with 5.565" rods, unless you use $$$Mallory metal$$$. It takes right about $300 just of the metal itseslf, not counting the labor, to internally balance a 400 crank. At that point, the stock rods quit being cheap. A big enough counterweight made of the same metal the crank is, won't fit between the centerline of the crank and the bottom of the piston at BDC. That's why the 400 is externally balanced in the first place.

Your choices (without going the Mallory metal route) are: get an externally balanced crank and 5.565" rods, buy a balancer and flywheel, and re-use your existing pistons; or, get an internally balanced crank and 5.7" or longer rods, buy new pistons, and re-use your existing bolt-ons.

Factor in the price of all that machine work you're already talking about, plus new rings, bearings, gaskets, fluids, etc.; as well as your time and risk.

Are the pistons REALLY that expensive, in the grand scheme of things? a 5% hit to the cost of the project, MAYBE 10%? Would you REALLY cheeep out that little tiny bit, in exchange for such an inferior setup, when the BETTER setup is such a small incremental expense?

I know which way I'd go. And it wouldn't be the stock 400 rods.

 

[bigjimzlll]

Bigjimzll...why do you say that?

Basically from what I've heard. Also an engine builder who I trust said so(about Eagle vs Scat) you around Mike?

 

[dmccoy72]

If I went the route of buying an internally balanced crank, could I just reuse my 5.7" rods and pistons I already have in it? How much of a benefit would it be for me to move from 5.7" to 6" rods?

I found a kit on EBAY that sells:
HawksRacing cast 8000 nodular iron crank,
5140 forged I-beam rods (bushed) w/ARP loc bolts
keith black hyp. pistons (9.7 comp for me)
All rings/bearings

all this for about $600 and for balancing an extra $190

What do you think?

 

[RB69SS396Conv]

No, you can't re-use your existing pistons and rods with the longer stroke.

The pistons will stick out the top of the block about 1/8" at TDC if you try that.

Who/what is HawksRacing? Is that a division of the Chinese People's Army? Do you really want a cast nodular iron (basically stock) crank, except from somebody you've never heard of?

 

[dmccoy72]

ok, well then other than the crank in that set up, i can upgrade that to a forged steel of like an extra 160 or so....Im in college and on a pretty tight budget so I can't afford the top of the line, Callies or anyting.

Would getting the Scat Pro Comp 9000 383 crank be the best route for me? It says that it will work with 5.7 rods and that is what I have

 

[bigjimzlll]

check out this site...Has good deals and are trust worthy.
http://www.cnc-motorsports.com/

BTW, I'm originally from St. Pete...and I will be moving back with in an year

 

[dmccoy72]

Thanks for that website bigjimzlll! Im gonna be ordering a rotating assembly from them for sure!

What would be the difference/benefit of getting an internally or externally balanced 383 kit with 5.7" rods? If its internally balanced they balance it with the rods, pistons, ect... and send it ready to install, if its externally balanced they include the damper and flex plate that is needed with it.

The same if true for kits with 6" rods but they are a little more expensive...
What would you guys recommend and why?

THANKS!!!!!!

 

[RB69SS396Conv]

Yeah I hear what you're saying about the high-$$$ stuff; but the flip side of that is, what if you buy the cheeeep stuff and something goes wrong, then what have you REALLY "saved"? Sometimes it's better to spend a scosch more up front, and improve the long-term odds of success and satisfaction.

That CNC Motorsports guy has been selling lots of stuff for quite some time now, and has good feedback; that's usually a good sign. Plus, they're at least name-brand, known-quantity type parts. I've never bought anything off of them but they look to be as good a risk as anybody.

The 6" rod version will make marginally more power than the 5.7" (almost certainly less than 2% difference, probably less than 1%). On the other hand, the ring setup is better with the shorter rod, because the rings have more space to live in between the wrist pin and the top of the piston, so the odds are in favor of them lasting longer.

Either one will leave enough room for the counterweights to be large enough for the motor to be internally balanced.

IMO there's no compelling reason, in a street build like this, to go with the longer rod. That's just opinion though; this isn't an "exact science" kind of thing, but rather a judgement call.

 

[dmccoy72]

Thanks! What about the internal or external balance part of it though? The internal balanced kit is a little more and comes ready to install, but the external balance kit comes with the damper and flex plate.

any thoughts/comments on which one of these i should go with, or does it matter?