pwrtripls1

After spending a few hours reading here It seems pretty cheap and easy to get big power out of these old trucks, so I am wondering at what point would i have to get a built 727 to hold the power?

My original intention was to reach 600 TQ at the flywheel, but they seem to go way past that and be really reliable still. So at this point with only $500 invested so far I may see how much power i can make, up to the tranny limmitations.

Anyway, thans for the help.

pwrtripls1

Nobody has a clue? I here there bullet proof, but i dont want to go over board with power first and blow the tranny.

jiMMyCTD

at least then you will have an idea of how much they can hold and report back

pwrtripls1

Well you have quite a few mods and are on the stock tranny right? So it must hold 600 crank TQ.

jiMMyCTD

we will find out, towing today for the weekend 6k lbs with the most recent gov spring and fuel pin. but yeah its holding fine and shift fine still.

Mcmopar

I've had them behind 440's and 493's putting out over 600 ft/lbs, but that was at like 4000 rpm, not 1700, sooooo I would guess yes, buuuut???? Methinksyouareonyourown!! Sorry

apwatson50

I think that you really need a tq converter so that more oil flows at higher pressures at lower rpms, where the torque is. And maybe a different valve body, then they will hold some power

Winr

There are lots of little mods you can do to a 727 to make it hold up to just about anything. Im my experience what hurts them most is high RPM and heat.
So you will have that in your favor. Keep it cool and it will hold up.

pwrtripls1

Thanks for the info guys, i think i may go all out.

Holsteinman

The torque converter will not last! I can not understand why anyone would want to turn up the power much with the stock converter. Over some time by brother has toasted his converter and he does not have insane power like some on here. The big thing he has is POD injectors. From the very first time he had PODs he could overpower and decouple the converter. My brothers truck will spank mine all day long, but he has always needed a better converter with the power he has.

Good Luck, Paul

redhornet

I think the key to tranny longevity in our trucks is the temperature guage,I dont think anyone should pull anything with a turned up CTD without a guage,I pull a 26 ft fifth wheel camper that weighs7800#,and if I push it hard,I can reach 240* trans temp on a mild hill,or even on the flat at 60mph and a head wind.

I also pull a 30' flat deck,with a 10,000# man lift on it,and I cannot pull it at 55mph in overdrive at all,the tc will simply slip and heat

ps:install temp guage in the cooler tube exiting the tranny

dont let it get over 230*before you throw it outa overdrive.

pwrtripls1

240* is way too hot! My race truck with a 4000rpm Yank stall only hits 200* after a few long burnouts and nitrous runs. Usually i can run it hard around town all day in the heat and it doesnt get up to 180*

Begle1

So you can overtemp the tranny running without a trailer?

If a few long burn-outs can overtemp the tranny at 4000 RPM, can extended cruising at 3000 over temp the tranny as well?

What about extended cruising at stock with the pedal to the metal?


I thought the tranny temp wasn't an issue if your weren't towing...

Bushy

Some of the things that cause temp issues are slippage of the TC and internal slippage due to insufficient pressures.
If you can keep the RPM above stall (about 1800-2000RPM on a stock convertor) you will help yourself to be sure. Also needed is to raise the line pressures a bit. You can use a VB shift kit. This will help you out by reducing the slippage internally.

Keep in mind on a stock system the line pressure tweaking is bit of a balancing act. You need to tweak 'em up a bit but not too much or you'll go thru seals.
You can also use a different ATF as well....try using Dexron type II or even Ford true type "F" if you can find it.
These have fewer friction modifiers (lower lubrication properties) and will give you firmer shifts, which in turn, means less slippage and better "grab".

To minimize your temps use as low a gear as possible to get you rolling without turning 3000RPM's kinda thing....
Once your moving, try to keep your RPM above stall and that will reduce slippage and help keep temps down as much as possible.
Finally, invest in a good aftermarket auxillary cooler....they are worth the bucks and then some...If you install a gauge and find your temps are still high you can install two coolers....they're cheaper than a full meal deal TC/VB/Tranny until your budget permits.

The early trucks all ran hotter than the later models...they went to lockup TC's for that reason. Since we use fluid coupling only we run hotter.
You can see temps of 230*F or even 250*F....in fact the 91.5 - 93's with OD have a thermo switch set to force you out of OD or prevent the upshift into OD when the temp reaches .......wait for it..........275*F ....

Don't ask me,,,, I have NO idea what they were thinking on that one....
pb....

rebal

my tranny is bone stock and with all the mods I have yet to see 200* untill i tow. the hottest i have seen it with a 10k trailer up a 7% 2 mile grade was 270*foot too the floor all the way. I herd the 727s run hot ,all i know is I use amsoil in it and have ever since 25k and its holding on. I have run this same trans with a no prisoners attitude for as long as i can remember. its bleedin pritty bad (oil leaks) and when it R.I.P a DTT is going in .I have killed a 727 behind a 440 (never ran synthetics before)and have wondered how good rebuilds are. the local trans shop has told me the old 727s were the toughest trans ever built. just the fact that a cummins in front of one proves that .and mods on top of a stock one to boot. good old MoPaR wish it was still a U.S. company