For those of you who race a 350 transmission with a trans brake. Please give me your feedback about doing so. Have you raced with both a Powerglide and 350 trans?

Yes.
A TH-350 with a trans brake doesn't last long, and the range ratios aren't optimum.
Speaking of high 6 second 1/8th mile car at 3000 lbs. plus.

I think I got a total of 18 runs on one before it was shredded internally. I got slightly more runs out of the 2 pukeglitches I owned.

60' times will be slightly different, but the end ET should be near identical, the obvious consistency choice will be the ......er,....ummmm, pukeglitch.

I said what I said.

For the best of all worlds (fun to drive, consistent,and durability), a custom ratio TH-400 is the answer.

I have, and do, run both. 350 brake, 3250 lbs sbc, broke input shaft, twice. put a glide w/brake in it, and put the 350 in a 2500 lb car. No problems, so far, roughly 500 passes. I blamed it on the weight. I should say it was, and is, a stock input.

Many moons ago we ran a turbo 350 with a brake. At that time, we weighed 3200 lbs. with driver; 9" slicks, 4.56 gears with a 383 sbc/550 hp. I called it our un-predictable trans. It would last anywhere between 10-100 passes.

The best thing we did was switch to the powerglide even though we were supposed to be too heavy for one.

2BKING

I ran T350's for years with no problems or failures. Last one was with a brake that I bough here on DRR in pieces, had been disassembled for rebuild and I bought it like that. I built it and it worked fine for years. Car weighed 3k with driver went a best of 6.5's. I went to a glide to calm down the starting line ratio as it is on 10.5 tires. The first T350 I ran was full manual and the only thing it had was a hardened race on the 2nd gear sprag. I was careful not to come out of a burnout in 2nd and let it grab, always came out in 3rd. The transbrake one had a new direct drum with the better sprag and race on it. Both had a lot of passes on them and both were working fine when I sold them, I mean a lot of passes on the first one.

Just looked at some of my old notes, 412 passes on the T350 with a brake. Only thing I ever did to it was change the fluid, I used Valvoline Dexron. Only thing I had to change was I tied the line lock to the transbrake so it didn't move when staging.

Did a number of TH350's for racers back in the day. They never last long, but those guys were warned ahead of time. I quit doing them eventually, and directed folks to do a PG or if they had to have 3 speeds, TH400. Or better yet, Liberty.