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Okay I didn't win 82sbshortbed won. Anyway on a different thread dealing with ESC some people get away with it and think things are fine others don't have the same experience. Bucket asked why, SirRobyn0 gave his 2 cents,and I gave mine,but I think 1 thing we all missed is 1 hei isn't all HEIs dozens if not hundreds of combinations,eccentric,weights springs amount of centrifugal in the distributor,amount of vacuum in the can and what what hg. the can drops in and out. So maybe at least part of the difference is exactly which HEI you install.
Right and that's a really good point about all the combinations and I'm sure plays a roll in how an ESC bypass works out.
I don't know how much help I'm going to be but I will give you what I have. As I understand it the stock vacuum advance can pulls 20 inches. I never measured mine when it was installed. Against you advice I'm running a Pertronix D9006 Flame-Thrower Adjustable Vacuum Advance Canister. For some unknown reason I have to limit my vac advance to about 16 degrees. But I'm running an aftermarket distributor a Ritchporter part # GM14, also sold by Orielly's under the WIA brand. My original distributor was SHOT, though I still have it. Centrifugal advance comes in super early I think it's pretty much all in by 1,500RPM, which might be why I can't run the full vac advance. That's pretty much what I can tell you. I no longer have a working distributor machine, so anytime I fool around it has to be on the car and I don't know the full #'s I've never really checked. What I do know is power is back and ping is rare, so this is working for me.
I can't really tell you what the stock distributor did, I never checked when my OEM distributor was in there and I've never checked total timing in the current one. I've just seen how fast the mechanical timing comes in and where it stops going up but never turned the dial on the timing light to get a number. Other than having some continued issues with the vacuum advance which prompted me to swap the adjustable unit back in. EGR works great so it's not that. I just think this aftermarket distributor has a little to much overlap. Or it's just my high mileage 305, but the thing has much better power now. It's to bad though I think I have an exhaust valve on it's way out, so I'll have to decide this winter if I want to tear into that 305 and do a valve job or drop in a 350..... I kind of hate to do either. I swore I wouldn't do major internal work on the 305 but now that I have stuff like the ESC functioning properly I hate to throw all that work away if I install a 350.
And that's actually a really good point. I "think" I've never seen one, but have heard that there were a few 350's that did roll with the ESC. The only reason not to would be the difficulty in getting a good module if mine ever croaks again. To that end I suppose the answer is not to overdue it with the compression, but to use the ESC to put a little more advance in particularly at cruse and it might do a little better for mileage than a regular 350. That way I would be able to run without the ESC if needed in the future without so many complications like on the 305. Sounds like a plan.
Your absolutely right, without a doubt a limiter combined with a better vac advance can, would likely be better. Heck I still have the original can from my original distributor I could use and limit. But at the time I needed to use the truck and I had the adjustable can on hand, and it's working well enough that I haven't made the time to tinker with it further.
