SB64

Just wanted to know if there are any differences in these distributors. Physically or internally. Would it make a difference since I have a 350/350 Quad at Lars, should I mate with a 350/350 dist. Any thoughts???

Brcmpbl

I hope someone else offers an opinion on this one, because I'm not certain in my answer...but I think they are the same mechanically.

Easy Mike

Don't quote me on this, but I believe the difference between the two amounts to springs, weights, and (possibly) the vacuum advance can.

Revi

You'll be fine with the distributor. You'll most likely modify with the light spring set and a B-26 vacuum can.

ezobens

The cam plate is probably different based on the difference of the max advance degrees on the chart- But that can be adjusted with bushings or altering the length of the slot in the cam plate.
The shape of the cam on the main shaft may differ as well but I don't think that should be a show stopper.

Brcmpbl

That's what I was thinking, just the bits would be different but not the major mechanics, based on different timing specs, etc. Good to know for future.

lars

All Chevy distributors (big block and small block) share the same housing and basic components, and will physically interchange (except 409). All Chevy distributors are set up very conservatively in their stock configuration, with only a handful of the high performance applications using a somewhat aggressive advance curve. The only differences between any of the distributors, whether it's a 350-horse Vette or a Caprice Station Wagon unit, are the following parameters:

1. Length of the mechanical advance curve. Determined by the length of the advance curve slot.
2. "Quickness" of the advance curve. Determined by the springs.
3. Shape of the curve. Determined by the shape of the shaft cam plate and the weights being used ("tail" length on the weights).
4. Characteristics of the vacuum advance curve, determined by the vacuum advance control unit.

All of these parameters can be easily tailored to produce a good performance curve on any distributor, regardless what that distributor came out of. And it's highly recommended that you do so, regardless of which distributor you have: Any distributor is going to have a pretty lousy curve - even the "performance" aftermarket units out of the box. Curving the ignition system is the biggest horsepower gain per buck you can do, and makes a much greater difference in power output than any carb tuning and carb setup you can do (on the dyno, we'll typically see horsepower changes in the 20hp range with timing/ignition curve changes, whereas carb jetting optimization typically will see gains of 5hp or-so).

The setup is easiest done on a distributor machine (I can do that for you), but you can also use your engine as a "distributor machine" if you have a dial-back timing light. My timing papers explain how to set up the curve and what the desired "numbers" are - you can e-mail me for a copy so you can check and alter your setup.

Lars
V8FastCars@msn.com