Yesterday I scored (probably a misnomer) a SBC Mallory dual point distributer; part number 2664501 at a swap meet. It is missing the rotor and cap which I have found on-line and would have replaced anyway. The reason it was so cheap is that the entire tach drive is missing. Where that part goes there is just empty space; the male threads on one end and female threads on the other end of the gear housing. So far I haven't found any source for that part/those parts. Anyone got any suggestions? I probably will not ever use it, but wish it were complete so someone could use it. If I can't make it complete then maybe someone on here has one with a cracked or damaged housing that can use it to complete his/hers. I've got next to nothing in it moneywise If you need it or want it shoot me a PM. I figure that anyone who knows what this thing is doesn't need pix, but if it's necessary let me know and I'll take some and post them.
Investigate to see if a Corvette tack drive is same animal, worth a try! Or maybe Vertex or any other tack drive mag...………………..
http://old.marinepartssource.com/crusaderpb/3507dp47.asp The tach drive I believe is reversible, meaning it can be installed from either end to accommodate clockwise and counterclockwise rotating tachs. Which ever end is used there is a plug for the opposing end. If not used at all, both ends could be plugged...
I would seriously look at the worm gear on the main shaft, it could be the reason the rest of it is missing. If it's toast, the plugs are the best option. Knock the roll pin out of the bottom, slide the gear off and the shaft will slide out. Make sure you mark the orientation clocking of how the gear came off, it needs to go back on the same. I have a Mallory flat cap and GM points that both have tach provisions, and will check to see if they are threaded the same, and/or identify the threads so you can find plugs...
https://www.ebay.ca/itm/MALLORY-257...ash=item2f437976e4:g:5cAAAOSwYAReyqpC&vxp=mtr You could easily spend more on parts than what its worth
The threads on the mallory(flat top) tach drive are what I believe 11/16-18, the GM cast iron tach drive threads are physically larger and do not interchange.
They were used on more boats than Corvettes. Seem to remember a couple kicking around the shop somewhere. I'll ask my partner if he has any use for them. jack vines
The threaded plug and opposing side should have the same threads, going from Mallory to another Mallory but I would check the main shaft worm gear where they mate, if its shot you would need a new main shaft.
I think I'll just cut it up and make a "pre-oiler" for new/rebuilt engines. Before that does anyone want it to use as a distributer? I've got $10 in it but if you'll come get it (central Missouri) you can have it for free.
Brass freeze plugs come in a lot of sizes,an so do rubber plugs,if your not going to use drive anyway !
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