Getting a hot street motor together for my big block duster and I figured it wouldn't be a bad idea to protect my feet from a trans explosion. Blanket? shield ? What are you using and why?

This is a street car and will see the track with drag radials from time to time. Automatic on the column if linkage matters. Would love to have it on the floor but for the price of A body buckets I may just keep my bench seat.

Have the trans properly built, install an aftermarket billet front clutch drum, a bolt in over running clutch helps. A low band apply valve body offers a tad more help in preventing over run clutch roller spit back.

A shield or blanket is “suspenders on a belt” after doing the above.

And of course, drive the car correctly.

Next question.

We use a shield as they have less chance of fouling stuff when installed, we have all the upgrades mentioned below plus steel planetaries, h/d i/p and o/p shafts etc. I've never seen one explode at the track but I have heard of a guy blowing one apart way back doing neutral drops or some other type of abuse. As has been mentioned, correct operation of the trans will help too.
Vid covers what needs to be done to minimize the risk.

https://www.youtube.com/watch?v=trUfoiS2Mew

I've said this here many times before. NSS racer almost lost his foot when the tranny went and the shield did NOTHING. It disappeared in a cloud of dust and only some Kevlar fibers remained intact on the bell housing bolts. The gas pedal did more. Feel a shield, then feel a blanket. Tell me which feels like it could absorb a 2 pound fragment at speed. I find it hard to believe a shield passes certification. Good luck.

I totally agree I have seen several carbon fiber shields fail in keeping shrapnel out of the car. Spend the money and buy the right parts to be safe, and a blanket will keep the shrapnel out of the car.

Thanks for all the replies. I have my old 727 from my 73 Charger from 20 years ago that had a forward pattern manual valve body but no low band apply (which I did not like for street driving).My local trans builder retired as well.

Now to find someone trustworthy with 727 experience close to central NC. I have no problems doing it with the right parts the first time. If only there was a reputable place close by without shipping. Time to start checking around.

Thanks and Merry Christmas to all.

My friend and I raced the trans for years and never a problem, his was a 10.90 440 Dart and mine was a 426 Max. The biggest safety feature is that thing between your ears. On My later Duster race car I used the stock column shifter with the detent made to use the reverse VB. AFTER doing burnout, stop, put it back in first, put a little pressure to set the spragg. If any part of driveline breaks pull the trans and check spragg.

A good drum is the most important. Along with correct driving habits mentioned. I’ve personally never broke a drum on any trans that I’ve built, Easily over 100 units. Found damaged low roller clutches. Even with low band apply. My racecar never hurt the factory roller clutch. It has broke two ultimate low rollers. Neither time did it show any issue. Only noticed when sheet metal spring parts were found in the pan during service. If you chose the HD (C6 Ford style) low roller make sure the sheet metal tabs clear the inner race. If they rub it will break them off. Also on the billet steel drum. I’ve switched to using 5.0 levers. Those drums are so heavy it takes all you can do to grip them on the 1-2 shift.
Doug

You can probably do it yourself. They are one of the easiest and most simple designs to work on with a minimum of special tools. I did my first one on the garage floor when I was 15 and it worked great in my cousin's AMX.

Gus

Blanket. Shield available on the web never fit properly. I have 2 blankets, one has Kevlar. He’s not close, but pro trans did mine.

100 percent!!! I've been racing Hemi SS cars for over 50 years with no issue. I do use a blanket. There is more chance of blowing your foot off with a street car, than a race car. You overturn the sprag and blow them up by overunning it low gear. Mr hot shot blowing the tires off to impress the kids, put a set of meats on so it hooks and k=pow! NO low gear burnouts, no blowing the tires off it. I use low to leave the starting line, pull it on the trailer, and pull in the garage. If you break a driveshaft or rear, overrev it in low, crawl under it in check it. Use your head, do thing right and respect you equipment and you will have no issue.

I had a 8 3/4 rear end fail in low gear which ended up making the rear sprag fail on my 1968 or later drag race 727

thyis happen to me 10 years ago with parts and oil came inside.i had a shield.when it happens its at the line when you take off in 1st

^^^Scary Sh!t there!!!^^^

I run a SFI bell and an SFI Shield.

Real easy to feel when spragg is rolled over. Put in first, if it feels like it in second-sluggish very weird, it’s gone. It’ll blow in first only, if it’s bad the thin sun gear driving shell-rear clutch drum will turn almost 3 times the engine rpm, and turns into a saw with those ‘teeth’. I’m now inclined to use a low band apply type VB but wondering if it applys in high gear too.

Buddy of mine had a healthy small block, 904 combo in a Dart. Broke the 8 3/4 under power. Fixed the rear and was out driving the car around. Had a very slight vibration. Called me and said he was going to the track and whether I though it would be OK. I told him to take it out and bring it to me. He said it drives fine. I said bring it to me.

Half the springs were crushed and the rollers were loose in the thing. Half the rollers were functioning well enough to drive the car around. Would not have survived the first hit. No idea what valve body was in it other than it was a manual.

A failed roller clutch doesn't necessarily mean the car won't move. And in a 727 with a stock drum, it would be a ticking bomb.

I'd switch to a th400 or powerglide before I'd run a blanket or shield again. Blanket is a nightmare with melted straps and acting like a sponge, and the shield is pricey. I'd do the above with a billet drum and proper VB on anything that's going to rev.

My thoughts; A Turbo 400 can spit a drum as well. Just happens at the stripe instead of the starting line. TCI shield is less than $300. If nothing leaks there is nothing to absorb when using a blanket.
Doug