86 C10 H-code needs a new distributor, recommendations? anything to avoid at all cost?

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silverbackreef

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More sorting out the truck's situation.

While trying to set base timing I noticed some odd behavior. Each time I tested it (before setting), I'd get something different (vac advance disconnected).

The an old Mallory 8548201 that they don't seem to acknowledge any more.

A look under the cap after (#%$^$^%U$T!!!!) removing it (not a fan of the 'wire hold-down' style cap in this case)
revealed the photo below: it's quite dirty and the weights are rusty. Pretty grainy feeling while trying to move them and they'll stick closed, stick wide open, and stick anywhere in-between.

As I see it, two options:
- tear it apart, clean everything, and hope it all works, or
- buy a new one.

I'm inclined to buy a new one but would like to hear some input on what to trust, or not.

This is for a stock 305 block and heads, holley 4160 600cfm, and edelbrock eps performer manifold, no computer control on advance.

Thanks for your input. I'm pretty new to the SBC world.

-Mark
 

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fast 99

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Clean and lube weights make sure they will advance not stuck, check vacuum advance, inspect white and green wires close to pickup coil for wear [actually I give them a light tug] remove module and reapply silicone grease. They are very dependable units.

If centrifugal advance is stuck it is relatively easy to fix that too.
 

hogdaddy

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silverbackreef

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Appreciate the input!

I started down that path and managed to lose a couple of small parts, dagnabbit!

Ordered a Proform from summit. I don't have a lot of $$$ in this truck and can afford some new parts for reliability. Based on what I've read, I'll have a good look at the new one before installation.
 

SirRobyn0

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I think the biggest thing is that sometimes the aftermarket distributors aren't calibrated properly or don't have a very good compactor for electrical interference, so hang on to the old distributor incase you have to swap springs and weights or whatever over to the new unit, if it doesn't want to run right.
 

hogdaddy

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Proform is made in China. It has good reviews and for $99 not bad.
 
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silverbackreef

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Thanks guys.

I ordered the extra weights and springs kit in case adjustments are necessary. $7, hard to say no. Planning to run off ported vacuum so not too worried. Will get a stop kit if I need to change to manifold vac.

Appreciate the input,
-M

PS: this is all pre-work for a carb rebuild that's waiting on parts, hopefully receive them before the end of the year. Proof of success won't come until the carb's done and I've finished cleaning up all the vacuum leaks.
 

silverbackreef

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Update:
* New Proform distributor arrived
* Pulled old one and compared (photos attached)
- All the parts of the old one are beefier but I don't see anything too objectionable
* Looked deeper into the old one and discovered the vac advance wasn't working either...
* Installed new one, set initial timing to about 10, checked that mechanical and (ported) vacuum advances were working, yup
* Test drive resulted in a lot of pinging under load
* Set initial timing and idle to values on emissions sticker (4 degrees @ 650(P)), retested and all seems good

I'm going to keep the old distributor. Upon further inspection, it seems fine as long as I replace the offending parts. If the Proform becomes a problem, I'll rebuild the Mallory and use that.

Final post unless the Proform misbehaves.
 

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GTX63

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Proform is made in China. It has good reviews and for $99 not bad.

I have used Proform and have had no issues. Now, with some other China made ignition parts, beware. Stay away from the no name ebay $59 all in one distributors that come complete with a pretty red cap. They sound like a quick and cheap fix when in reality they bear no resemblance to a quality distributor. I have had a coil burn out of one within 300 miles, and another that had no working advance and wouldn't pull a scarecrow down a hill.
 

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