Full disclaimer: I know little about cars, I have a mechanic who's always worked on my '86 MC SS since my wife gave it to me as a complete surprise a few years ago. So if you're willing, be patient with my ignorance
Within the last year I had the mechanic put a 350 in it. Very recently I had him take out the auto transmission and put in a (supposedly nearly-new) 4-speed Saginaw. He says the shifter is a 'Summit Racing' model based off the Hurst. Must admit, I REALLY like having a manual in it!
So yesterday I drove it, it was doing OK (OK as usual; see below), parked at a store, when I came out I tried to back up. At first it seemed like I couldn't get it in reverse (still not sure the shifter will actually go where it's supposed to go to be in reverse). But when the shifter feels like it's in neutral, it's actually in reverse. When I put it in 1st and let out the clutch, it goes nowhere and dies. In 'neutral', it's in reverse.
So my mechanic (who is ~ 1/2 hour away from me) says it's probably the 'shift rods' and they need to be moved, to do that have to get underneath the car. If I can get someone to do that (I'm a little older and not very nimble) then I can hopefully get it back to him to see why they stuck, if that's actually what it is.
Meanwhile: Ever since he put the manual in, the higher the speed it's at (NOT the RPMs), the more the shifter 'buzzes', an annoying high speed rattle/vibration. He's checked it, says everything looks OK, he doesn't think it's hurting anything. He says he's checking with the shifter manufacturer to see if they know anything about it.
Any comments/suggestions?