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Manual valve body, Low/reverse band apply?

Posted By: itali83

Manual valve body, Low/reverse band apply? - 05/21/08 09:11 PM

Hey guys, I would like to know a little more about which style manual valve body is "better" than the other for a BB 727. Here's the deal with my tranny. I had the local mopar tranny "guru" help me build my tranny. It's behind a 500ish HP 440 in my 68 bird with 4:10's. He swore up and down I don't need a bolt in sprag, so I didn't get one, he swore that I didn't need a valve body with low/reverse apply in first so I didn't get one. I got a reverse pattern manual with no band apply. He says that the set up he's been running for years and years in his 62? belverdere or imperial (what ever it is, it's a huge boat) that he drag races with a dana 60 4:56's full race slicks and he pulls the front wheels off the line. I saw the car, saw pics, talked to others around town and he's a legit guy. Only recently have I been doing some reading up on this and found differing opinions on the bolt in sprag and low apply band. I plan on drag racing my car but also streeting it. I don't want to hear anything about how I'll hate the manual part, no I won't and I purposely wanted it that way. I just want to know if anyone has a similar set up and how it has worked for them. Also I would like to know any techniques that will keep my tranny in one piece. Thanks for any help!
Posted By: ram87

Re: Manual valve body, Low/reverse band apply? - 05/21/08 09:31 PM

I wouldn't think you would need the low band apply valve body unless you are going to race the car frequently. I have a forward manual valve body with low band apply. I really like it because it prevents low gear overrun. I start my burnouts in 2nd gear and shift to 3rd at about 5000 rpm. This is easier on the transmission than beginning a burnout in low gear. I, like you, don't mind the manual shifting at all. You just have to remember to manually shift the car down at stop lights. I don't know whether you need a bolt in sprag or not. I don't have one and I haven't had any problems with my transmission.

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Posted By: dvw

Re: Manual valve body, Low/reverse band apply? - 05/22/08 02:34 AM

I have run both. The non apply I ran for 20 years with no problem. If you are in 1st gear and let off the throttle you need to ease back in to it,don't slam it down or you could damage the low roller clutch. 2 years ago I changed to a LBA. A trans shield does not fit on my street car. It has gone 11.05 so I figured it might be a good idea. I can't get used to it on the street. When coasting down to a stop I used to shift to 1st. Now when I do it downshifts,NOW. Driven properly they both work. When racing, you really should have a shield. My new race car (should go low 9) does not have LBA but it does have a shield.
Doug
Posted By: dave571

Re: Manual valve body, Low/reverse band apply? - 05/22/08 03:18 AM

I think the grey area is continually growing on this issue.
Many will say a stock 727 is nearly indestructable.

My buddy ran a 388" small block in an A body. Weighed around 3500 pounds with driver.
The cars best et was in the mid 11's at sea level.

Running low 12's at another track, it blew wide open. Lucky not to lose a limb. 727 with stock 12 pin sprag, and a non low band apply VB.

My own car wieghs closer to 3800. Running about 1/10 slower than the previously mentioned A body. Same trans, 727 with nlba.

When his blew open, I decided I would go with a low band apply valve body in my car to help avoid the same issue.

When I went to install it, I found chunks of 1 way springs(from the sprague) in the pan

Pulled it apart. Debris had chewed up the output shaft so bad, I had to replace it. and best of all, there were only 2 of the 12 springs left holding it together. I was 1 hard hit away from blowing mine all over the place too

In anycase, now I have the billet drum, 16 pin bolt in one way, heavy bands and clutches, and low band apply valve body.

I sleep better now.
Posted By: itali83

Re: Manual valve body, Low/reverse band apply? - 05/22/08 09:59 AM

Thanks guys. I plan on running a shield no matter what it takes to make it fit just as a safety measure. I'm just asking because I don't have the tranny in the car yet and am kinda having second thoughts while I still have it out. Now here's my second question. If I run a bolt in sprag, there is still the possibility of overturning the springs and causing catastrophic damage right? Just the whole sprag won't spin in the case? From what I know, and understand, it sounds like I should either leave my tranny alone, or do everything, bolt in sprag, LBA valve body and billet drum. I just kinda figured that if they made non apply valve bodies for so long and had so many cars that will be faster than mine it must be alright. Thanks again!
Posted By: MNobody

Re: Manual valve body, Low/reverse band apply? - 05/22/08 10:40 AM

I'm running a reverse manual in mine, not sure if it's LBA or not but it just coast's if you downshift to first, no engine braking. So far no problem's but i only downshift to first when i'm sitting still anyway.
Posted By: dvw

Re: Manual valve body, Low/reverse band apply? - 05/22/08 11:34 AM

I run the stock low roller clutch. I've seen the worst damage often does not rip the outter race out of the case. The damage is because the rollers couldn't hold the inner race. This almost always results from a instant shock load,not smooth apply.
Doug
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