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Author Topic:   5.7 or 6
Dirt Full Roller

Total posts: 66
posted November 30, 2005 12:53 PM  
I am looking to build a 383 for next year and was wondering if i should use a 5.7 or 6 rod? What are the pros and cons of both?

Dirt Freak

Total posts: 231
posted November 30, 2005 09:01 PM  
6" - makes for a far better rod ratio, which will increase durability.

rods and pistons are a little more expensive but not much.

Dirt Full Roller

Total posts: 43
posted November 30, 2005 10:16 PM  
When I first started racing, we priced up a 5.7 Rod motor, and a 6" Rod motor. The 6" Rod motor would have cost $160 more to build.

Go 6" for sure, you'll be happier in the end.

Flying Jack Ace
Dirt Roller

Total posts: 14
posted December 01, 2005 05:45 AM  
It's usually cheaper to balance a 6" rod motor. Some guys don't like the 6" rod because the lower ring land on the piston crosses the pin area. As for performance between the 2 there is negliglble difference.

Ego Racing
Dirt Forum Champ
Total posts: 762
posted December 01, 2005 07:03 AM  
Performance might not much difference as in HP. You will however lower the side load on the on the piston skirts and on the block bore and lower the torsion load on the crankshaft. It should run alot longer without parts damage.

Dirt Roller

Total posts: 13
posted December 04, 2005 09:14 PM  
The 6" rods allow for a lighter piston weight too. The difference in Rod weight is negligible, but the pistons for the longer rods are considerably lighter, plus when the crank gets balanced they'll take an equivalent amount off the counter weights.

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