SteFunk

Got a1980 Toyota truck 20r engine, needs a vacuum advance. Doing searches I'm only finding 22r vacuum advance.
Has anyone put a 22r vacuum advance on a 20r distributor? If so are there any tweaks that need done?

13Swords

From what I understand, the 20R & 22R distributors are basically the same mechanically, with the exception of the vac advance. The 20R usually has the single diaphragm, 22R has the double diaphragm. I've read of people sticking a 22R distributor into a 20R and having it work. You would also have to hook up the vac line to the diaphragm closest to the distributor for advance, & cap the back one off if you're de-smogged. Otherwise if you're still running the stock vac lines you can also hook up the rear diaphragm. It's actually a distributor timing retard instead of advance, & is supposed to work with your stock emissions setup. Lots of people only run the advance & cap off the retard feature.

BTW, from what I see of parts, the '80 has the double diaphragm like the 22R, so I don't see what the difference would be. Looks like '80 was the first year for that; the '79 & earlier has the single diaphragm (I have a '78).

Other suggestion is use the one you've got for a core exchange & get a correct & freshly rebuilt distributor from Rock Auto. It's less than $90 ($86.79 plus shipping), has a brand new vac advance already installed, new pickup coil, is basically a drop in & has a limited lifetime warranty to boot. Here's the link to it if you wanna have a look:

https://www.rockauto.com/en/catalog/...stributor,7108

A1 CARDONE 31726

Best of luck with it.