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Author Topic:   5.7 or 6.0 383 ?
Dirt Roller

Total posts: 23
posted October 16, 2005 10:07 AM  
I am building a 383 this winter and was wondering if a 5.7 or 6.0 rod 383 is best? The carb is a 350 Holley. 4 barell intake. Compression will be 13 or 14 to one. Max RPM will be around 6750.

Dirt Freak

Total posts: 209
posted October 16, 2005 07:26 PM  

Dirt Forum Racer

Total posts: 81
posted October 20, 2005 09:43 PM  

Dirt Forum Champ
Total posts: 1876
posted October 20, 2005 10:33 PM  
6.0, i prefer too ru nas long as rod as possible for almost all applications. I run a 6.350 long one in my main motor. But hands down, 6.0 rod.

Dirt Full Roller

Total posts: 52
posted October 21, 2005 09:42 AM  

Dirt Roller

Total posts: 7
posted November 03, 2005 12:42 PM  
When you use a 6" rod instead of the 5.7" one, do you need a crank change also or just the piston change?
I'm building a .030" over 350 and was going to use speedpro hyperutetic coated pistons with powder metal rods, but upon browsing other piston questions and your answers, I think I'll change to JE SRP and 6" rods.

Dirt Forum Champ
Total posts: 796
posted November 03, 2005 02:38 PM  
The difference between a 5.7" rod crank and a 6.0" rod crank is the weight of the coutner balance weights. The big chunk of metal opposite side of the rods.

A 6.0" rod crank has more weight on it so it can be balanced easier. You can run a 5.7" rod crank, but they will probaly need to add some mallory metal in there to make up the weight.

Pistons, same drill. Lighter pistons are easier on the rods due to the reciprocating weight as well.

Add the rod, bolts, bearings, piston, pin, and rings plus retainers up and then you have to balance that against the counter weight. Heavier rod & pistons require more counterweight.

[This message has been edited by Kromulous (edited November 03, 2005).]

Dirt Full Roller

Total posts: 48
posted November 03, 2005 03:07 PM  
I read in smokey Yunick's book that the ideal rod length for a small block chevy was like a 6.5" rod. Obviously this isn't possible but I thought he had said that the longer rod keeps the piston at top dead center longer and makes more horsepower. I would go with as long a rod as possible.

Dirt Forum Champ
Total posts: 1876
posted November 03, 2005 03:19 PM  
I run a 6.350 rod motor, if people would like more info, pm me.

Dirt Maniac

Total posts: 104
posted November 06, 2005 08:00 PM  
im building one right now with 6.8 rods

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