The advance curve for a SBC is VASTLY different than the advance curve on a flatty. I know there are conversion kits and guys that do this for a living (GMC Bubba for example) so HOW is a SBC distributor modified for an acceptable curve on a totally different engine? I know this is a very common and popular conversion, so there MUST be a solution that I just don't understand. My understanding is that the flathead should be set at zero degrees initial, but with the SBC distributor it's recommended to set them at six degrees BTDC. (I still don't get why the zero thing) I'm trying to figure out what's best for my 8BA, thanks for the help.
Bill, thanks for the link. Now the SBC conversion scares me even more. I'm having trouble grasping why its so popular. Maybe I'll look into a Pertronix conversion for the stock dizzy.
I bought a sbc distributor for the flathead and it worked great, it just didn't "look" right to me. So I went back to the stock distributor with pertronix and all is well. What ever makes you happy, either is better than points in my opinion.
The points aren't the problem with a stock distributer, it's the advance. I've been running Bubba's conversion for a few years and it works great, totally mechanical advance. The stocker will still work, but only properly if you're running the single carb so you get the correct amount of vacuum for the advance. Flatman
That's the problem, its a warmed over flattie with two-twos. Bubba is well repected, but the SBC advance curve doesn't equate to what works with a flattie, unless he has some magical way of changing the advance... mechanical, of course. I'm thinking a stock dizzy with Pertronix may be the best way for me. No disrespect to Bubba or anyone else, this just doesn't equate.
I'm thinking that Bubba pretty well recurves the majority of the distributors he does for the individual engine setup it's going in. I don't know if he does it this way but if it were me I'd have the distributors setting on th shelf already modified and rebuilt and when an order came in I'd put it in the distributor machine and work the magic on it to match the purchaser's engine specs. Then in the box and over on the shipping table ready to go out with that day's shipment. The one he does for me may not be just right for someone else's engine with a different cam and carb setup. I used to work for a guy who was the go to guy in Central Texas to have your Mallory dual point set up for circle track racing and he set the curve on every one to suit the engine setup that the owner was running. I still don't know what he did on them but every week at least a couple of racers would show up distributor in hand to have him set them up.
I just had RonnieRoadster do an old two piece cap Mallory for my flathead build. Distributor, by the factory plate, was curved for a Corvette. Ron does the Petronix conversion and then sets the distributor up on a Sun machine (remember those?) so it is right for the application.
It's not "magic" but it IS a reflection of his expertise in knowing how a mechanical advance system works. It's not "rocket science" either. With changes in springs he alters the rate of advance and with set screws he sets the limit of total advance. He knows what Flatheads like so he sets the distributor accordingly. If you think you have something unique, tell him up front and the Chevy conversion will come back to you ready to run.
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