Was at the Mopar Nationals this past weekend, running in Sportsman. Still sorting the car out, but on Friday had two good passes. First was a 13.06 and then a 12.89, after the second pass the car started giving me issues. I noticed after that pass that at idle the car was down about 300 rpms, so i adjusted the idle up some cause at that time i didnt think anything of it. Well the next pass i make the car pulls hard from 1st to 2nd shifting about 5300, and when in second it pulls hard until it gets to 4000 and it starts to breakup. It does this from 4000 till my 5300 shift to third, and does the same thing in third. After that pass i attempted to fix the issue at the track, but had no luck and aborted the pass as soon as it broke up. So i checked the timing today and i had it set at 22 intial at 900 and 37 total, and today it got 10 degrees intial at 900. Thoughts on what caused this?

Update: took the cap off the dizzy. This is a photo of the rotor, as you can see its bent and burn marks are on it. On the inside of the cap, where the coil wire is, is worn and seems to have been scraped. Any ideas on this?

Bent upper distributor shaft - where the reluctor or cam sits. Common problem when the rotor sticks on the shaft and is pried off with a screw driver.

common problem? can't say I've ever heard of that, but anything's possible. Seems it would have to be bent pretty dang bad for that to occur. At this point I'd venture to guess the rotor may not have been seated all the way. I'd try another.... and post up some picts of the car. I have a soft spot for Miradas

Well on my dads car the rotor fit is really snug, and on mine it is significantly less. To the point to where i think it could be possible the rotor came up and hit the top of the cap. Still scratching my head on loss of rpms and timing, any ideas appreciated.

as requested.

HA! ....same scoop I used to run. Sold mine in 2012 after owning it 26 years. Was 318, then warmed up 340 4bbl, 340 six pak (fit under stock hood), 340 4bbl/nitrous, and the final mill was a low buck 498 RB that got my ride down in the 9.9's at Famoso. Kind of miss the car, but we kept the 70 Duster in the family.

Have you checked the vertical play on your distributor shaft?

Nice Mirada BTW, there used to be a red one with t tops around here that was beautiful.

Just putting the cap on a bit off will cause it

Well i was leaning toward that scoop, when i came across a picture of your car.

A few people i talked to suggested timing chain, even though it was put together a year and a half ago, so i deceided to take it apart. Got it tore apart and all seems in order, but its late and ill double check everything tomorrow. Just curious if an adjustable rocker being out of adjustment could cause this? Thank you for the suggestions thus far and would appreciate any more ideas.