Anybody Do a 727 to Th400 Swap?
 

I'm working on putting a Turbo 400 in my 90 W250 right now. Anyone else done this conersion?:humm:

i dont think a built turbo 400 could hold up to even a stock cummins i heard someone on here saying he went though 3 th 400 with a stock cummins

I agree . Thou you could build a 400 to handle the power it would be a waste of money. Just The money spent buying the bellhousing ,adapter ,flexplate, and transfer case adapter would be better spent building the 727 . The 727 is a very stout trans and with a few mods (steel planetary,extra clutches,H.D. pump,ext.. ) can easly handle all the power a ve pump can make. Also the 727 is more efficent and weighs less than the turbo 400 !

Been there. Broke that.
 

The first time I killed the 727 it blew the sprag out of the case. Seems a 10 ton trailer full of logs was a bit much. I got that one rebuilt with a bolt in sprag all was well. Til I did a half throttle take off and pulled the bolt in sprag out. I have a 68 Chevelle with a 400 that I have ABUSED forever with no problem(yea yea i know gas car vs truck). I already have the whole set up bolted in my truck now. Just finishing a few more things on it. I hope it will be worth the time and money spent. I was just trying to see if anyone had already done the swap before me. Thanks.

I am pretty sure the TH400 is just as strong, if not stronger than a 727. Although for the same amount of money you could build the 727 better after you pay for the adapter plate,custom TC and what not. 4bt and 6bt have the same bellhousing bolt pattern, don't they? If you had a bread truck with a 4bt and TH400 layin around, that'd save you some cash. And there is a 11 SEC Chevelle with a Dmax and TH400 in Diesel Power Mag. If you're gonna go all custom, why not start with a TH425? Just my .02c.:pca1:

what did the th425 come out off?
what about a 700r4, would one on them hold up?
plus you would have od

700R4 are junk!
 

Had four in a 6.2 chevy. They are junk even with low horse power. I know you can get them built strong but I would never own one.
I have a bread truck TH475 and adapter plate. Found a guy in TN who bought 100 bread trucks :bat: to part out. And a found a guy who needed my 727 NP205 and had a TH400 NP205 to trade me. Jack pot!:jump: Cause they are rare and pricy!

does that guy in TN have any more of those TH475'S ???

If your going through all thi strouble to swap trannys... Why not swap in a tranny with a lock up?

because its costy... lol i'm probably going to be shelling out almost 4k on a goerend trans and convertor with a hardened or billet input and intermediate shaft... if he's got the resources to do it cheap then i guess it cant hurt. the lock-up sure is a nice addition tho.

You can build a decent lock-up for cheap... Wont be top teh line but it will be better then stock. Your gonna spend some coin on the T400 swap and you will gain nothing. The 400 and 727 are about on par with each other when built.

Didnt cost that much.
 

Only got $1500 in the conversion. Go to 4BTswap.com to find the bread truck conversions. The guys name is bob he puts 4Bts in old military trucks.

The TH400 is rated for 450 ft lbs, as opposed to 400 ft lbs for the TF727.(stock ratings) The TH350 takes 36 hp to turn, the TH400 takes approx 44 hp to turn, more than a 727, less than a C6. The main difference between a TH475 and a TH400 is the 475 has straight cut gears, which are inherently stronger than the 400's helical cut gears.

You can build an ok OD tranny for a little more then that.

And much louder.

X2 Straight cut gears are very noisy.

Ever drive an old Chevy with a Muncie M22 4 spd? They're not that loud, but you can definitely hear gear whine. If you got the stereo cranked you won't hear it at all!:w2:But if you're only saving a couple hundred bucks with the TH4?!, you should do a 47RH, much better tranny.

Over drive
 

I don't really care about OD. My truck is not a daily driver I only use it to pull trailers and ride around. And by the time you buy a good lock up converter you would spend $$$$ so I'm good with my 400.:choochoo:

A stock 400 will do no better then a stock 727 in your truck. We are just trying to say its alot of work and a good bit of money for nothing gained other then being able to say.... I got a TH400 in my truck. for a few bucks more you could put mild built 47rh (single disc converter, good clutches and steels, VB) that will hold up easy to anything most 1st gens put out. Also a lock up tranny will tow ALOT better.

Also what is the length difference between the 727 and the 400? if its much at all don't forget about the new drive shafts you will need to buy.

For a budget built mild tranny.... Get a well used 47rh (around $300) and then use Kit #K47-2.

PATC 46RE 47RE 48RE Transmissions, Performance Transmission A518, 518

Total $1,384 in parts... hmmm... Still need some odds and ends but your pretty close to the same $1,500 you quoted your 400 at... And you gained a gear and lock-up. Wont live up to 600HP but would be a nice tranny for a 400hp street terror.

Somehow, I think this data is flawed. 400 lb ft is nothing for a stock 727. 727s have been bolted behind gas engines that had more than 400 lb. ft. of torque (426 HEMI, 440 6pak, etc...) for years. The later Cummins versions are a bit stronger than the 70's models....so I'm thinking that 400 lb ft is crap. :laugh:

A stock 727 is still stronger than a stock TH400. The 727 can be built to hold a LOT of HP and Torque. It was the only HD trans offered by Mopar for YEARS. Look at most stock/super stock drag cars of the 60s and 70s.... I've abused a few, and all have served very well.