727 vs powerglide

Posted By: WO23Coronet

727 vs powerglide - 01/31/13 03:48 AM

K, with all the tranny questions lately about replacing a 727 with a powerglide (and 727/904 questions in general) when a car gets to a certain point, it got me thinking, why don't guys just put higher gears in the diff and keep the 727, using 1st and 2nd? IE:

Powerglide: 1.76 (low gear) x 4.10 (diff)= 7.216 overall ratio, and a 4.10 overall high gear

727: 2.45 (1st gear) x 2.94 (diff)= 7.203 overall ratio, and 1.45 (2nd) x 2.94 = 4.263 overall ratio

Pretty much bang on, with the added benefit of a 2.94 overall in 3rd if you actually drive your car on the highway.

Is it the added strength of the Powerglide? The better torque convertors you can get for them? It's got to be something because I'm surely not the first guy in the world to think of this

Posted By: Mopar-Al

Re: 727 vs powerglide - 01/31/13 03:52 AM

2.94 gear is for an 8 3/4 ? I can usually bust those gears up in 1 or 2 hard launches.

Posted By: domingo

Re: 727 vs powerglide - 01/31/13 04:01 AM

I hear a powerglide is stronger than a 727, or there is affordable aftermaket stuff to make it stronger...and cheaper...

Not sure about that though....

Posted By: Leon441

Re: 727 vs powerglide - 01/31/13 04:14 AM

I don't know about stronger or cheaper.

That's a relavent statement.

A fairly stock 727 with a good drum that will not blow up with a sprag failure can handle about 600 lbs of torque with no problem. The next step is the gearset. An aftermarket or deisel truck one will withstand about anything. So depending on your skill or cost of your transmission guy you can build a 727 that will withstand any Race Mopar I know of for about $2,000 in parts.

A stock powerglide will handle 600 lbs of torque. Then it is input shaft, planetary, pump, output housing to handle about 800 lbs of torque. Then add more clutches aftermarket case tailhousing. You can easily spend $2,500 in parts.

The powerglide has the same individual clutch area as a 904. In fact the 8 clutch packs are 904 clutches. But, the clutches being smaller take less HP and their are no drums changing directions on the shift. So many argue that powerglides are faster. Depends light car with a wide powerband. Absolutely powerglide. High winding or narrow powerband, heavy car. 727 more gears.

Their is nothing wrong with either transmission if built properly. I run a glide because it is shorter in length. The 727 will not easily fit my chassis modifications. Otherwise that is exactly what would be in my car.

Would not dream of running a 2.94 with a torqueflite. 3.7 maybe. If you don't like a 2.44 first gear. Switch to something else like a 2.28, 2.05 or put a glide in the car. But, a car can be tuned for a 2.44 gear and a rear gear that will make the finish line.

Leon

Posted By: WO23Coronet

Re: 727 vs powerglide - 01/31/13 05:13 AM

Quote:

2.94 gear is for an 8 3/4 ? I can usually bust those gears up in 1 or 2 hard launches.

I know a 2.94 is for an 8 3/4, I just used that # for comparison, pretty sure u could get whatever gear set u wanted for a 9" Ford

Posted By: 67HEMI

Re: 727 vs powerglide - 01/31/13 10:27 PM

Southland Dodge did some testing on the V-10 drag pack challenger and they picked up around .3 with a tf over the pg.

Posted By: HotRodDave

Re: 727 vs powerglide - 02/01/13 02:21 AM

The guys who claim to run faster with a glide are few and far between and most of them probably would have been better off just getting the proper rear gear in the car. A gear drive for TQ multiplication is more efficient then a slipping converter any day of the week.

Posted By: Winchester 73

Re: 727 vs powerglide - 02/01/13 03:24 AM

Quote:

2.94 gear is for an 8 3/4 ? I can usually bust those gears up in 1 or 2 hard launches.

ive heard the dana 61 housings only go as HIGH as 3.08,they make spools for them as well.

Posted By: Kevins493

Re: 727 vs powerglide - 02/01/13 05:12 AM

Quote:

I don't know about stronger or cheaper.

That's a relavent statement.

A fairly stock 727 with a good drum that will not blow up with a sprag failure can handle about 600 lbs of torque with no problem. The next step is the gearset. An aftermarket or deisel truck one will withstand about anything. So depending on your skill or cost of your transmission guy you can build a 727 that will withstand any Race Mopar I know of for about $2,000 in parts.

A stock powerglide will handle 600 lbs of torque. Then it is input shaft, planetary, pump, output housing to handle about 800 lbs of torque. Then add more clutches aftermarket case tailhousing. You can easily spend $2,500 in parts.

The powerglide has the same individual clutch area as a 904. In fact the 8 clutch packs are 904 clutches. But, the clutches being smaller take less HP and their are no drums changing directions on the shift. So many argue that powerglides are faster. Depends light car with a wide powerband. Absolutely powerglide. High winding or narrow powerband, heavy car. 727 more gears.

Their is nothing wrong with either transmission if built properly. I run a glide because it is shorter in length. The 727 will not easily fit my chassis modifications. Otherwise that is exactly what would be in my car.

Would not dream of running a 2.94 with a torqueflite. 3.7 maybe. If you don't like a 2.44 first gear. Switch to something else like a 2.28, 2.05 or put a glide in the car. But, a car can be tuned for a 2.44 gear and a rear gear that will make the finish line.

Leon

I would add that the converter is usually going to be much more critical on a powerglide as far as the combination goes, and in applications like Comp the 727 has been found to be at least a tenth (seem to remember two) faster due to the narrow powerband. If I was building a BB powered dragster or tube car, I would absolutely go with a glide. It would just be more consistent. If I was running class legal/heads up with a SB or a 99Hemi and had to run an auto (and wasn't tire limited), I would likely go with a 727.

Posted By: jamesc

Re: 727 vs powerglide - 02/01/13 05:15 AM

Quote:

The guys who claim to run faster with a glide are few and far between and most of them probably would have been better off just getting the proper rear gear in the car. A gear drive for TQ multiplication is more efficient then a slipping converter any day of the week.

it depends on your goals and combination. i bracket race so for me winning rounds is much more important than absolute ET performance.

Posted By: instigator

Re: 727 vs powerglide - 02/01/13 06:49 AM

A butt load of torque through a 727 with weight behind it seems to be a problem also.....that's why a 1.80 straight cut reid cased glide is sitting on my workbench now.....

Posted By: GTX MATT

Re: 727 vs powerglide - 02/01/13 07:17 AM

My daily driver Lumina had an internal electrical failure in the tranny that sent it into limp mode. 2nd gear starts (with the selector in 1 or 2) and manual shifts to 3rd. I drove it around for a couple weeks before I swapped the tranny out, joking that I had a race Glide in it.

I guess since most race cars have manual valve bodies anyway one could build a TF and start in second gear if they really wanted a Glide.

The true answer is probably (without knowing anything about whats out there) that there is much more aftermarket stuff available at a reasonable price for the Glide, and obviously having less gears makes the construction simpler, allowing for more durability. I'd bet its aftermarket though, same reason a 350 is the greatest engine ever and a Ford 9 inch is bulletproof.

Posted By: Bob_Coomer

Re: 727 vs powerglide - 02/01/13 07:06 PM

not sure how anyone can compare to diff transmissions like that to performance. Its hard to say, which converter is a better match? How can none have two identical converters for two diff transmissions? The PG 1.76 is plenty strong... been 1.0x short times with a stick 1.76 gear set and 2000+ lbs car... Also ran 850HP Mopars behind 90% stock 727 too in heavy cars... 3700+ lbs.... Its not cheap to switch either. Unless your starting from scratch

Posted By: 70Dart499

Re: 727 vs powerglide - 02/01/13 07:53 PM

Wasn't someone working on a trans brake valve body for the 727 that would allow you to use the trans brake in second gear, and this making a 727 a two speed? I was very curious to see if it ever went into production, because I think it would be a great idea, becuase really the only plus to a glide is the fact that it is 2-speed. I run my 727 in only second and third all the time, and I only lose about .10, and the car is more consistent.

Posted By: jamesc

Re: 727 vs powerglide - 02/01/13 07:55 PM

Quote:

because really the only plus to a glide is the fact that it is 2-speed

ever weighed the two not to mention some of that is rotating

Posted By: 70Dart499

Re: 727 vs powerglide - 02/01/13 08:32 PM

Yes, I know 'glides are lighter, I was talking more from a consistency standpoint than anything else, and I should have been more specific. I'll be honest, I'm putting a transbrake in the car before too long, and its going to be a 'glide, so I didn't mean to sound like I didnt like them.