I finally got around to converting the CHEAP swap meet SBC Mallory magneto to fit an early hemi. Both the SBC and the early hemi's have clockwise distributor rotation. I've seen a number of guys buy the sbc converting setups. They are basically a sleeve that goes around the stock length sbc distributor housing and puts the actual distributor way the heck up in the air. Yuck!!! Not for me. First off I took the magneto apart and cut the housing down to length on the lathe. I pressed out the bushing from the bottom piece I cut off and put it in the bottom of the shortened housing. I trued up the mounting flange so it would fit the adapter tight. Next I whitled an adapter with an interferance fit to the distributor housing, so it would fit in the block like a stock distributor. Once that was pressed on I put the shaft back in, marked where the roll pin was needed for the retaining ring, and drilled it. Once the retaining ring and washers was back on and the pin hammered in I cut the shaft to the same length as the hemi distributor. Finally I ground the end of the shaft into the locating tab. Fun little project this evening.
Not sure what you mean buy a standard mag base Dave. I did some research and found a mallory ad of this thing.
Since the mid to late 60s mallory and the other brands started using a standard base that clamps onto the bottom of the mag itself and contains the drive mechanism. So basically you get the mag and the base to install it in whatever motor you want. I guess it really doesn't matter because the world won't miss another SBC part, and your machinework is cheaper than finding a new base, and that one has the timing marks and a tach drive....
You know, now I'm curious. Am I the only ultra cheap guy here? I never gave a thought to looking for the "right" base. I got this cheap and right off I knew I could make it work. Heck, I would have bought it regardless at that price.
No... I've picked up a few cheap vertex mags for an SBC with the intent of doing the same thing. way cheaper than paying hemi prices.
YOU ARE A RULER!!!!! Thank you for posting this tech!! Could you possibly do a sketch or something of the various steps and input shaft and maybe throw on the critical dimensions for making this work? Again... AWESOME! Can't wait to see how this works out! Keep the info coming man! Great timing by the way... just might be looking into this for the fate of my next build!
I'll try and get something drawn out this week. I pretty much just copied dimensions off of an existing hemi distributor but I'll give more complete dimensions and a dimension specific pic of the adapter.
Is that a Mallory Supermag? I bought one (model 310 SP) for a SBC with the intent to convert to a Ford flathead. But then I heard about wiring issues being difficult without a special "starter box" that originally came with the unit. I'm very interested in watching how you hook this one up. Do you have all the cap and rotor stuff? FYI, my cap is the same as a DuCoil cap, but doesn't actually have the brass ring inside for the second coil. But I have seen other pics with different caps as well.
Good idea and great work! Been thinkin' this same with sbc/nailhead, I just haven't found sbc magneto yet from any swapmeet. If I remember right, some guy from Sweden made that conversion from sbc-magneto to nailhead's magneto. If I remember right, he sacrificed one nailhead stock distributor for that project. It was here at HAMB, something like two years ago or such...
Right when I thought my own cheapness was well documented here - you have to ask this!!!! ha ha ha. Nice work - good to see real Hot Rodding is truely still alive. Do you plan on adding any weld or are you planning to rely entirely on the press fit?? Last time I fiddled with these I noticed that the tang width is different from Chevy to Hemi - just thought I'd mention if in case you hadn't already posted that. Looks nice.
Thanks for the kind words guys. It is indeed a supermag Alchemy. I don't have a cap or a rotor. That's another conversion project. It has an adapter of sorts for the cap already so I thought I'd make my own to fit a Mopar cap. Adapting a Mopar roter is going to be the tricky part. Still pondering the best way to do it. I'd not heard of a starter box but this thing has a big fat spark at the points so I'd be surprised if it doesn't work once the coil is hooked up. I'm not going to weld it HemiRambler. It fit pretty good. As far as the tab at the bottom, both the Chevy and Hemi shafts were the same diameter. I just ground the tab to the same width as the stock one. Later when I tried the fit in an intermediate shaft it was looser than I want. I'm going to weld and regrind for a tighter fit. I did use a mopar ring and pin at the bottom. I suppose you could cut up and use part of the Chevy gear but that's to much work for me. ;-)
Yep!!! Still waiting for my bent tube so I can get busy. I might just tear into the engine and/or the trans soon it I have to keep waiting. I'm running out of little projects for her.
I just dug out my old magazine article about putting one of these in a street car, and they talk about a Mini-Mag, even though it looks just like this Supermag. But they say the PowerPak box contains the coil and some relays to allow a regular ignition switch to start and operate the engine. Unlike other mags set up with a grounding kill switch. Is this going in your coupe, or the dragster? Maybe you could use some sort of epoxy to mold the bottom of the rotor to the exact shape of the center shaft. Just hog out the rotor, fill it full of epoxy, and shove it over the oiled shaft to get a perfect fit.
Interesting about the article. I've got a couple of the red topped Mallory Super-Mag transformers to choose from. I figured I'd rig up a basic grounding switch. This is going in the digger. I'd like the look of a magneto in the coupe but I have the current ignition working so well I hate to mess with it. The adapter for the rotor needs to be on the shaft to allow stock (cheap) rotors. It'll be another lathe project probably. I modified this one to fit a 331-354 hemi but there's no reason you couldn't modify it for the 241-270 Dodge. The shaft length is the only difference.
good to see kerry, another period piece for the dragster. might have to file this one away for down the track.
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