TH350 or TH400?? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

sjarrett71 · 02-24-2011, 08:19 PM

Say you had a 72 GMC with a 350 engine that was an occasional daily driver. If you had the opportunity to put either a TH350 or a TH400 in your truck which one would you choose and why?

1low · 02-24-2011, 08:27 PM

th400 there stronger and dont have a kickdown cable but the th350 is just fine just my thoughts

kaycee · 02-24-2011, 09:29 PM

It all depends on what I had before either 1 and you would/might have to alter driveshaft rear trans. mount.The 400 is tuff when built right has an electric kickdown versus the cable for the 350.I have ran 350 that I built myself and they are strong and plenty around.So if I'm not pushing a bunch of HP I would get a 350

sjarrett71 · 02-24-2011, 09:42 PM

Definately not a bunch of horsepower. Just have both available and wondering which one I should install. I will keep the other as a backup.

CG · 02-24-2011, 10:04 PM

A Turbo 400 takes around (if I recall correctly) 35 more horses to run. So it does rob your engine some over a turbo 350.

Livrat has a big block in his 4x4 and he runs the heck outta that thing. Lots of towing etc etc and he told me his turbo 350 has held up just fine for thousands of miles.

sjarrett71 · 02-24-2011, 10:20 PM

I've heard that about the 400 also but don't know how factual it is. I know people have them behind 350's and do fine with them. I guess that's why I asked, to get peoples experiences and suggestions.

CSmith · 02-24-2011, 10:23 PM

Unless you have a monster engine or do a lot of towing a 400 is only going to rob power.

1low · 02-24-2011, 10:24 PM

Ya the 400 does rob more power but i read in chevy high performance that u will actually run better times with the 400.

Willys47 · 02-25-2011, 12:28 AM

that may have to do with the gearing

Livrat · 02-25-2011, 12:46 AM

Quote:

Originally Posted by CG

A Turbo 400 takes around (if I recall correctly) 35 more horses to run. So it does rob your engine some over a turbo 350.

Livrat has a big block in his 4x4 and he runs the heck outta that thing. Lots of towing etc etc and he told me his turbo 350 has held up just fine for thousands of miles.

Both are good transmission but I opt for the T-350.. as CG says.. it takes less HP to run and has a lower first gear than a T400, I have a t350 with a shift kit and a motorhome T400 converter (has a lower stall speed than most) in my 5800lb 4X4 running a 468 inch built big block and run it to death pulling a car trailer with all kinds of loads, it has 85k miles on it so far it still going strong.

ETsC10 · 02-25-2011, 01:04 AM

They are both great trannys. T400s are very durable.
But, T350s are good too and can probably be upgraded cheaper.
(not sure about that, maybe someone can chime in.)

If you aren't working your truck a bunch, a stock T350 (easy to find,
upgrade, rebuild, etc) should be fine and then some. I have a T400
behind my 327 street truck and it's fine also. It's what I have.

I would choose depending what driveshaft/yoke you have available.
Keep the other and keep it's yoke if you have to change it in the future.

Another thought~ Though I'm a T400 enthusiast, I would think T350
is probably stock for your truck.

OK ~ that's my 12 cents.

cdowns · 02-25-2011, 07:56 AM

i'd go with an overdrive tranny anytime i'd need to make a choice

lofly'a · 02-25-2011, 08:16 AM

i agree with ccdowns all around as far as driveability and mileage gains, although for an occasional driver i'd opt for the 350 as far as low cost to build, maintain, perform and drive and there are so many options to make it a fun to drive transmission no matter what your needs are. the 400 is more bullet-proof in stock form and is only marginally more expensive than a 350 not considering the power loss versus the 350.

MARKDTN · 02-25-2011, 11:31 AM

Forced to choose between the 2, I would probably go with a TH400 just because it is more bulletproof. If I went with a TH350 it would be stone stock-no shift kit, no hi stall converter, and no lockup version. The TH350 is a good transmission but when it goes it can splatter. The "built" ones seem worse IMHO than the stock ones. The lockup version has issues with pumps that you don't need.

Honestly, if you are going to swap, I'd go to a 700R4 and get overdrive.

brad_man_72 · 02-25-2011, 02:53 PM

I'd go th350 lower 1st gear woud make it more fun and be able to handle a highway gear better. I like to peel out so the lower gear and less power loss plays a big role in my decision. Dont tell the cops!

*stich626* · 02-25-2011, 03:10 PM

lower first gear??
2.42 is 2.42
with the choice and only a 350cid I'd go th350 why..
you can get a 200r4 and build it, and it bolts into the spot the th350 was..

brad_man_72 · 02-25-2011, 04:16 PM

I've heard the th350 has a lower 1st gear than the th400. I'm no trans guru.

sjarrett71 · 02-25-2011, 04:31 PM

I might go with an overdrive tranny but I don't have one. I only have the 350 and 400 tranny's.

cdowns · 02-25-2011, 04:57 PM

Quote:

Originally Posted by brad_man_72

I've heard the th350 has a lower 1st gear than the th400. I'm no trans guru.

most th350 have 252 first gear th400 have 248 first gear not much of a difference that you'd feel in the seat of the pants between the two

*stich626* · 02-25-2011, 05:31 PM

Quote:

Originally Posted by sjarrett71

I might go with an overdrive tranny but I don't have one. I only have the 350 and 400 tranny's.

but if you go with the th350 now, the 200r4 is a bolt in, same lenth, same yoke,

cam.man67 · 02-25-2011, 05:41 PM

I'd go with the 350 if it's just a standard DD. Plus, if you ever get tired of it, it's practically nothing to swap in a 2004r.

Sammy · 02-25-2011, 08:52 PM

I vote the TH350 because they are reliable and easier and cheaper to repair. Especially behind a stock sm block. Under normal driving conditions without constant abuse it should give you decent service. Even a reliable transmision shop echo'd this comment to me.

Jeffs70 · 02-25-2011, 09:48 PM

I never have had a TH400 in any of these trucks. My truck I have started to do a ground up on with my 383 stroker motor pushing around 500HP does pretty well with a TH350 and pulling me 0-60 MPH in just around 5 seconds I think thats doing pretty damn well. and never had a problem with it one bit. I also debated on changing but I seem to not have any problems so why should I change and then have to change other parts to get it to work.

crazy longhorn · 02-26-2011, 12:31 AM

400 T....you wont break it or wear it out. Under normal use, I have seen them run a 1/4 MILLION miles. I takes about 20 more ponies to pull it vs the 350 T....but after 250000 miles , who gives a chit? crazyL

badblu97 · 02-26-2011, 08:12 AM

I happen to be in the middle of this kinda swap, I have a th350, rebuilt, with a shift kit, and a 2100 stall torque converter that was meant for another project, but is going in my 66 with a stock 327....hope it all goes well for both of us!

02-24-2011, 08:19 PM	#1
sjarrett71 Registered User Join Date: Dec 2006 Location: Rolla, MO Posts: 2,463	TH350 or TH400?? Say you had a 72 GMC with a 350 engine that was an occasional daily driver. If you had the opportunity to put either a TH350 or a TH400 in your truck which one would you choose and why? __________________ -Scott- Last edited by sjarrett71; 02-24-2011 at 08:20 PM.

02-24-2011, 08:27 PM	#2
1low Registered User Join Date: Feb 2010 Location: Moyie Springs ID. Posts: 160	Re: TH350 or TH400?? th400 there stronger and dont have a kickdown cable but the th350 is just fine just my thoughts

02-24-2011, 09:29 PM	#3
kaycee Registered User Join Date: Jan 2000 Location: Wyoming USA Posts: 2,446	Re: TH350 or TH400?? It all depends on what I had before either 1 and you would/might have to alter driveshaft rear trans. mount.The 400 is tuff when built right has an electric kickdown versus the cable for the 350.I have ran 350 that I built myself and they are strong and plenty around.So if I'm not pushing a bunch of HP I would get a 350 __________________ 2001 Silverado K-1500 2005 FXDWG stage3 69 CHEVY Short/Step 327/4L60 373 posi 63 IMPALA 327

02-24-2011, 09:42 PM	#4
sjarrett71 Registered User Join Date: Dec 2006 Location: Rolla, MO Posts: 2,463	Re: TH350 or TH400?? Definately not a bunch of horsepower. Just have both available and wondering which one I should install. I will keep the other as a backup. __________________ -Scott-

02-24-2011, 10:04 PM	#5
CG BlahBlahBlah Join Date: Feb 2002 Location: Wa. Posts: 19,985	Re: TH350 or TH400?? A Turbo 400 takes around (if I recall correctly) 35 more horses to run. So it does rob your engine some over a turbo 350. Livrat has a big block in his 4x4 and he runs the heck outta that thing. Lots of towing etc etc and he told me his turbo 350 has held up just fine for thousands of miles. __________________ … … … … … … … … ... … … … … … … … … … … … Last edited by CG; 02-24-2011 at 10:06 PM.

02-24-2011, 10:20 PM	#6
sjarrett71 Registered User Join Date: Dec 2006 Location: Rolla, MO Posts: 2,463	Re: TH350 or TH400?? I've heard that about the 400 also but don't know how factual it is. I know people have them behind 350's and do fine with them. I guess that's why I asked, to get peoples experiences and suggestions. __________________ -Scott-

02-24-2011, 10:23 PM	#7
CSmith Registered User Join Date: May 2003 Location: Deer Park, WA Posts: 30	Re: TH350 or TH400?? Unless you have a monster engine or do a lot of towing a 400 is only going to rob power.

02-24-2011, 10:24 PM	#8
1low Registered User Join Date: Feb 2010 Location: Moyie Springs ID. Posts: 160	Re: TH350 or TH400?? Ya the 400 does rob more power but i read in chevy high performance that u will actually run better times with the 400.

02-25-2011, 12:28 AM	#9
Willys47 Registered User Join Date: Dec 2007 Location: Nanaimo B.C. Posts: 604	Re: TH350 or TH400?? that may have to do with the gearing __________________ I was hooked on these trucks since 1982 when I drove my budys fathers 1968 Custum GMC 396 automatic dana 60 rear with a power lock diff what a ride more fun then we will we can ever tell!!

02-25-2011, 01:04 AM	#11
ETsC10 Hand Crafted C-10 Join Date: Aug 2006 Location: Burien, WA Posts: 5,180	Re: TH350 or TH400?? They are both great trannys. T400s are very durable. But, T350s are good too and can probably be upgraded cheaper. (not sure about that, maybe someone can chime in.) If you aren't working your truck a bunch, a stock T350 (easy to find, upgrade, rebuild, etc) should be fine and then some. I have a T400 behind my 327 street truck and it's fine also. It's what I have. I would choose depending what driveshaft/yoke you have available. Keep the other and keep it's yoke if you have to change it in the future. Another thought~ Though I'm a T400 enthusiast, I would think T350 is probably stock for your truck. OK ~ that's my 12 cents. Last edited by ETsC10; 02-25-2011 at 01:10 AM.

02-25-2011, 07:56 AM	#12
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: TH350 or TH400?? i'd go with an overdrive tranny anytime i'd need to make a choice __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

02-25-2011, 08:16 AM	#13
lofly'a Registered User Join Date: May 2000 Location: Alexandria, LA 71301 Posts: 1,451	Re: TH350 or TH400?? i agree with ccdowns all around as far as driveability and mileage gains, although for an occasional driver i'd opt for the 350 as far as low cost to build, maintain, perform and drive and there are so many options to make it a fun to drive transmission no matter what your needs are. the 400 is more bullet-proof in stock form and is only marginally more expensive than a 350 not considering the power loss versus the 350. __________________ -02 avalanche (daily driver) -66 gto ragtop 389/400 (garage queen, hand-me-down from dad) -72 Tribute Trans Am (6.0LS/T56 6-speed) in progress -2003 YUKON (Wife's) -71 gmc swb fleet (current project, gonna shave everything, bags, stuff w/ 20's, gen III powertrain) -48 3100 SWB - 12/31/23 LONG TERM Project

02-25-2011, 11:31 AM	#14
MARKDTN Registered User Join Date: Jan 2011 Location: Chattanooga, TN Posts: 2,159	Re: TH350 or TH400?? Forced to choose between the 2, I would probably go with a TH400 just because it is more bulletproof. If I went with a TH350 it would be stone stock-no shift kit, no hi stall converter, and no lockup version. The TH350 is a good transmission but when it goes it can splatter. The "built" ones seem worse IMHO than the stock ones. The lockup version has issues with pumps that you don't need. Honestly, if you are going to swap, I'd go to a 700R4 and get overdrive. __________________ '83 K20-TPI '73 C10 '79 C10-ex-diesel(SOLD) '07 Tahoe(Son driving) '14 Suburban-DD '71 C10-current project

02-25-2011, 02:53 PM	#15
brad_man_72 the boat guy Join Date: Jul 2007 Location: springfield mo Posts: 2,339	Re: TH350 or TH400?? I'd go th350 lower 1st gear woud make it more fun and be able to handle a highway gear better. I like to peel out so the lower gear and less power loss plays a big role in my decision. Dont tell the cops!

02-25-2011, 03:10 PM	#16
stich626 Account Suspended Join Date: Sep 2010 Location: hingham ma Posts: 1,721	Re: TH350 or TH400?? lower first gear?? 2.42 is 2.42 with the choice and only a 350cid I'd go th350 why.. you can get a 200r4 and build it, and it bolts into the spot the th350 was..



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02-25-2011, 04:16 PM	#17
brad_man_72 the boat guy Join Date: Jul 2007 Location: springfield mo Posts: 2,339	Re: TH350 or TH400?? I've heard the th350 has a lower 1st gear than the th400. I'm no trans guru.

02-25-2011, 04:31 PM	#18
sjarrett71 Registered User Join Date: Dec 2006 Location: Rolla, MO Posts: 2,463	Re: TH350 or TH400?? I might go with an overdrive tranny but I don't have one. I only have the 350 and 400 tranny's. __________________ -Scott-

02-25-2011, 05:41 PM	#21
cam.man67 Registered User Join Date: Jun 2010 Location: Jefferson, MD Posts: 2,397	Re: TH350 or TH400?? I'd go with the 350 if it's just a standard DD. Plus, if you ever get tired of it, it's practically nothing to swap in a 2004r. __________________ '68 Dodge Dart 270, 225, 904, 2.76--"Lucy" 1996 Gmc 1500 Z71, 350, 4l60e, 3.73s 1995 Jeep Wrangler Rio Grande 2.5, AX5, 4.10s 1989 Toyota Pickup 22re, auto, 3.73

02-25-2011, 08:52 PM	#22
Sammy Registered User Join Date: Apr 2000 Location: Bonne Terre, Mo Posts: 3,005	Re: TH350 or TH400?? I vote the TH350 because they are reliable and easier and cheaper to repair. Especially behind a stock sm block. Under normal driving conditions without constant abuse it should give you decent service. Even a reliable transmision shop echo'd this comment to me. __________________ '69 Chevy Long Fleet & '71 GMC Short Step & Project "ODD BALL" "You can wash a pig, soak it in most expensive perfume. In the end it is still just a pig." ODD BALL build thread http://67-72chevytrucks.com/vboard/s...d.php?t=478629"

02-25-2011, 09:48 PM	#23
Jeffs70 Registered User Join Date: Oct 2007 Location: Valley Springs, Ca Posts: 857	Re: TH350 or TH400?? I never have had a TH400 in any of these trucks. My truck I have started to do a ground up on with my 383 stroker motor pushing around 500HP does pretty well with a TH350 and pulling me 0-60 MPH in just around 5 seconds I think thats doing pretty damn well. and never had a problem with it one bit. I also debated on changing but I seem to not have any problems so why should I change and then have to change other parts to get it to work. __________________ My Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=442487 My Picture Gallery http://67-72chevytrucks.com/gallery/...0&ppuser=36004

02-26-2011, 12:31 AM	#24
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	Re: TH350 or TH400?? 400 T....you wont break it or wear it out. Under normal use, I have seen them run a 1/4 MILLION miles. I takes about 20 more ponies to pull it vs the 350 T....but after 250000 miles , who gives a chit? crazyL __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

02-26-2011, 08:12 AM	#25
badblu97 Double 6's Join Date: Oct 2008 Location: Winter Haven, FL Posts: 349	Re: TH350 or TH400?? I happen to be in the middle of this kinda swap, I have a th350, rebuilt, with a shift kit, and a 2100 stall torque converter that was meant for another project, but is going in my 66 with a stock 327....hope it all goes well for both of us! __________________ Street Glidin! 1966 LWB Custom Cab (sold) 1982 Short Fleet (under the knife) 1998 S10 2wd Fleet 2007 Chevy Silverado Crew 2007 Harley Davidson Street Glide

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