Swapped out my 727 and 4500 flash convertor for a 904 and looser 5200 flash convertor in the offseason..... took awhile with rain to finally get out.........

First a little history........ car ran anywhere from generally high 11.40’s to high 11.50’s last summer. High 50’s were at Norwalk, probably worst air i had the car in last year..... first season on the combo..... ran more like 11.45-11.50 as it cooled off late last summer and into early fall. Only got out a very few times last year.....
Late last fall i had a mineshaft air type night to cap off the year. I had swapped to a radial so this was first time to try them..... i figured they would be a plus
Anyhow, car ran 11.40 off the trailer at 117.80 or so..... then 11.36, then 11.33, then capped off with personal best 11.26 at 118.40..... per my signature...... most mph’s were 116.50 to 117 and change in the summer
60 foots 1.61-1.63..... only single exception ever..... 1.58 on that last pass where it went 11.26

So i show up last night in what i suspected was probably 11.50-11.52 air going by last years results..... figured the tranny and vert were about a 3/10’s upgrade and figured on running high teens or low 20’s.

Well, night started with a ran out of gas, gurgling 11.71 pass........ added gas to tank to fix that..... lol.... stupid, not first time i have done that
Next pass car goes 11.46, missing in high gear( old plugs i figured) which i should have changed.....i look closer at the time slip...... 111.52 mph. Thats alarming, wasnt missing THAT much........1.55 60 foot though... best ever
Cool down a minute, make another lap.......11.39 at 113.55...... same 1.55 60 foot, same 1/8 mile times. Car pulls strong, no missing, runs fine.
Buddy says.... maybe it doesnt like those new mufflers you just put on it( raced with open headers every outling last year)....... so off they come( kooks units, like dynomax bullets)
Get in the lanes again.... 11.40 at 114.30....... nope, that wasnt it.....
At this point i am about done, little brother insisted i make one more pass...... so i go up with the intent to try something different.... all last year, and previously the passes earlier last night i launched the car at 2k off the foot. With the old convertor it pushed too much to leave any higher, and as i am generally racing, i am looking for consistency, and locking on that 2k mark on the tach is easy and repeatable.....
So with this new looser convertor i got it to 3k pretty easy and bumped in...... 11.374..... same exact 1.55 60 foot as all the others...... but 116.94 mph.... wow, welcome back, thats almost “ normal”

I look at the 60 foot, 1/8 mile mph and ET, this is a car to go to war with..... 7.20 or 7.21 on every pass, 94mph and change.
Top end mph is all over the place, even though times are quite consistent. I bought this Cope built 904 used, never even pulled the pan off. Its a 3,000 super pro unit with A&A brake, billet drum, yada, yada. Convertor is a PTC i gave good detail to them on what i had combo wise and what i wanted, and it got built and works seemingly exactly how i wanted it.
After talking to a good Moparts buddy this morning who has forgotten more than i know, among other things ge told me i should have checked( like taking the pan off the used tranny) he thinks the adj for for the 2/3 shift is way out of adjustment..... i thought going down track the 2/3 shift was ultra mushy and linear........ so...... ideas? Thoughts?
Would slipping on 2/3 shift account 100% for what i was seeing on the time slips..... sure seems to..........and be leaving mph and ET on the table