Typically a 383 is externally balanced. They do make stroker cranks that can be internally balanced. Are there any differences in the longevity of the motor when comparing how the motor is balanced (int. vs. ext.)?

Thanks,
Marc

mwh,

I don't know if there are longevity problems, but I will say this. I don't like the way the factory did the original 400 balancer. The "notch" cut in the damper is on the outside ring of the damper, which by the way is mounted on rubber. So, what happens is the "out-of-balance" has to transfer through the rubber ring. This creates a tendency for the outer ring to start wobbling and breaks loose from the rubber. IMO, if you are considering externally balancing, go with an aftermarket damper. My buddy just bought a PRO-RACE 400 damper. It has a removable counterweight. It was nice, and it allows you to go back to internally balanced in the future, just remove the weight. Hope this helps. Take care.

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69 SSRS Frame-off Resto
81 Z-28 377ci Drag Car

EXCELLENT TIP 69SSRS!!!!

Most aftermarket companies make an internally balanced stroker crank. They also have the added 'plus' of already having the correct main sizes for the application you are building. I have a SCAT crank and love it. I did put a SFI flex plate and an ATI balancer though.



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Mark
1992 Firebird 355/Six Speed
1991 RS 350 / Blown (As in Broke)
1987 Toyota Pickup 383 / 500 + HP
**How fast is just a matter of how much $$$ **

My two cents (for what its worth),

I personally don't think internal vs. external balancing makes that "big-a-difference" until you start "twisting" on your engine until you get it out of its manufactured design rpm use.
What I'm trying to say is that millions have been made both ways and they work "fine". BUT when you start to really produce some high rpm power, they last "longer" when they are balanced "finer or more uniform" in the reciprocating component area.
Theres less stock "out of balance" along the length of the cranks counterweights balance when everything is balanced internally to contend with even though everything is stock balanced overall externally. Like end to end.
Does this make sense?? pdq67

pdq67, It makes a big difference with new style one piece blocks. You cannot use a standard one piece block, with a 400 crank and a seal adapter with a six speed. The flywheels are different. Found this out the hard way once. Personally, I like the internally balanced cranks. You can use all the standard flywheels and balancers, plus no one will even know!



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Mark
1992 Firebird 355/Six Speed
1991 RS 350 / 700-R4
1987 Toyota Pickup 383 / 500 + HP
**How fast is just a matter of how much $$$ **

MarkW,

Isn't the Gen V and VI 454 and 502 external balanced and made with one piece rear seals??? The new 6 speed set-up has nothing to do with "balance" only "parts interchange".
I think I read somewhere that somebody is making two piece seal crank flywheels to fit the 6 speed combo but that the are "EXPENSIVE" because they are basically one-off custom made due to the extremely low volume involved.
IMHO, the Gen. made a BIG mistake getting away from the old style engines. Why??? Millions and millions of great engines can't be all bad. Sure, they weeped alittle, kinda like a "Harley Hog". So what!!! But in the stroke of a design drwawing pen, they obsoleted 30-40+ years of technology. pdq67

I guess they went to a one piece design so we could identify them as 'junk" at the swap meets. http://www.camaros.net/forum/wink.gif

The difference the six speed makes it the fact that Chevy never made a two piece crank that fit the one piece flywheel. I have a nice two piece 383 sitting here that I cannot run due to that same fact. They are making 'one off' cranks now, but you are right about the $$$.

Word of advice Chevrolet. "Don't fix it if it ain't broke!"

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Mark
1992 Firebird 355/Six Speed
1991 RS 350 / 700-R4
1987 Toyota Pickup 383 / 500 + HP
**How fast is just a matter of how much $$$ **