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Discussion Starter #1
This might be a bit of a dumb question, considering the timing, but during my engine swap, we came across a bit of a problem with our harmonic balancer. Jegs sent us one for a 400 engine which is externally balanced, while we ordered one for a 350 (they sent several wrong parts) but someone told my dad that the 305 balancer would be okay. We put it on and it went on, no problem. Tonight I took the car out for a cruise now that it is all put back together and tuned up. I mentioned the balancer issue to a friend who works at our local speed shop and he told me that a 305 balancer is a bad idea and that we should change it out before too long. The motor is running well with little to no noise from the engine, so we assumed that there was no problem, but what should we do? Should we get a 350 balancer? If so, how bad is it to use the 305 one for the time being. We would probably swap it out no later than next week.

Thanks for any info!

-Kris Horton
 

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You should be OK with it temporarily during the engine break-in, providing it's in good shape. The real problem here is that the rubber in the old balancer is probably old and breaking down and can work its way out. Just change it to a new one when it arrives, take it easy with the RPMs', and keep a close eye on it.

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Discussion Starter #3
Thanks!

Thanks for the quick reply! I'm taking it pretty easy for the first couple hundred miles anyway, but I just wanted to be sure I wasn't doing any harm to the motor. I think I've only opened up the secondaries twice so far. I'll feel better about driving it hard once it's broken in though and then it'll be back to the same ol' bad habits. :-D

Thanks again,
-Kris
 

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305 / 350 balancer

I have a305 balencer on a 350 in an 82 EC. The timing maks do not match and there appears to be a vibration issue, possibly the flex plate is an issue too?

I was told that at low RPM is would work but that it was not race grade. The previous owner kept the 305 parts when making a swap to a 350.

I am going to put a Fluid balancer on the 350 but I have to still check into the flex plate issue.

Any suggestions on Correct Methods?

Thx,

Diablo :evil: Doug
 

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Use a balancer for the 350 unless your going to a 383 then you can use the 400. Flex plate again use the one for the 350 not the 305. 305 is a different creature. Don't go down on the parts when building your 350 use the correct stuff. The other stuff might fit but it was not designed for that block/crank combination.

The elastometer is a essential piece of the engine. Use the best you can afford and if you can afford it a "Street Damper" by Fluid Damper is the best I have seen. 8" is a good size.

Don't use the Exhaust or the Intake or the heads, starter, fuel pump or Carb either off the 305 it is all trashable. Heads will not flow properly for the larger displacement, same for the intake, fuel pump. Starter should always be replaced. Also replace the Battery Cables with new ones, that is just good practice, and the water pump.

Anything you do use off an old engine will generally be the first thing to go wrong with the new engine.


Just my $0.02 worth.
 

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Thanks for the information. I thought that the damper was a replacer but I was not certain on the flex plate.

Have you had any experience with SUMMITs house brand of fluid damper for a 350? It may not be rated for competition but, we were only looking at Street legal classes any how.

THx,
Diablo :evil: Doug
 
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