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

HvyChevy454 · 01-06-2003, 05:13 PM

Are they the same length, short shaft or long?
Is the trans x member mount in the same place?
Will the torque converters swap?
Will the yokes swap?

Got a Th400 w/ a 2200 converter behind the 350 in the s10 daily driver
Got a Th350 w/ 1200 converter behind the 454 in the 72 weekend driver

I want to see if i can swap em w/ out much trouble?

HvyChevy454 · 01-06-2003, 11:46 PM

maybe i shoulda posted this on the trans board?

crazy longhorn · 01-06-2003, 11:56 PM

A short tail 400T is approx 11/16 longer than a short tail 350T. The slip yolks are a different size, & the trans crossmember locates in a different place. the converters will swap. TCI has case dimentions..... http://www.tciauto.com/tech_info/trans_dims.htm

Blackhawkdc · 01-06-2003, 11:57 PM

Quote:

Originally posted by HvyChevy454
Are they the same length, short shaft or long?
Is the trans x member mount in the same place?
Will the torque converters swap?
Will the yokes swap?

Got a Th400 w/ a 2200 converter behind the 350 in the s10 daily driver
Got a Th350 w/ 1200 converter behind the 454 in the 72 weekend driver

I want to see if i can swap em w/ out much trouble?

I'm not sure about length and crossmember positions. But I'm pretty sure that the torque convertors are not the same, and the driveshaft yokes are not the same.

crazy longhorn · 01-07-2003, 12:09 AM

The tork converters are not the same, the 400 generally had a larger dia converter......they will swap as long as the 350 isnt a lock up trans,& & you have both patterns on the flexplates. I have run the smaller dia converters on the 400t(thats usually what you get with a mild aftermarket verter)

HvyChevy454 · 01-07-2003, 12:27 AM

gracias crazy

crazy longhorn · 01-07-2003, 12:38 AM

you are welcome

**1971Stepside** · 01-07-2003, 11:09 AM

I took my 400 to my transmission guy and he actually recommended putting the 350 torque converter in it rather than the 400. As crazy longhorn said, that gives you the extra performance..

Longhorn Man · 01-08-2003, 12:17 AM

Yup, I had to install a TH400 verter into my Th350 so I could run it behinde the caddy engine.
The caddy only has TH400 holes drilled in the fly wheel.
Crazy, you think this will hurt my theoretical stall? It's all stock, so it's not like I had alot of stall to lose there.

crazy longhorn · 01-08-2003, 12:36 AM

I dont think it will hurt you too much longhorn, with the larger cube eng, & the gears in that 1 ton. The 70 delta that I drove home (455 /2brl) had a 400 t with the large verter.......it would boil the hides at will!

mikep · 01-08-2003, 12:37 AM

350 and 400 torque converter. Same thing. Sometimes the bolt patterns different. Sometimes its bigger in diameter depending on what vehicle it was under more than the type of tranny.

wxman1 · 01-08-2003, 03:15 AM

Can somebody educate me on what a stall converter
is and why its important?

Jim
Mt Juliet, TN

Project1970 · 01-08-2003, 03:21 AM

All converters are 'stall' converters - the difference is whether they stall at stock speed (roughly 1500RPM) or higher.

More or less, the stall speed is where a torque converter really 'bites'. You only need to worry about it if you're running a hot engine that doesn't have a whole lot of bottom end, or doesn't like to idle much. A stock converter, you'll generally have a hard time holding the vehicle still if you try to get the RPMs above 1500 or so...the higher 'stall' a converter is advertised with, the higher RPM you can do before it'll really try to move.

More or less...it's how guys with autos launch a vehicle at anything higher than 1800RPM.

01-06-2003, 05:13 PM	#1
HvyChevy454 Slowly getting CRSS... Join Date: Jul 2001 Location: Lutz, Florida Posts: 656	TH400 and TH350 Similarities? Are they the same length, short shaft or long? Is the trans x member mount in the same place? Will the torque converters swap? Will the yokes swap? Got a Th400 w/ a 2200 converter behind the 350 in the s10 daily driver Got a Th350 w/ 1200 converter behind the 454 in the 72 weekend driver I want to see if i can swap em w/ out much trouble? __________________ -Nic Lutz, Fl My Team Website The Heavy Chevy Website ------------------ 72 Cheyenne 10 LWB GM 12-bolt 3.08 w/ Auburn Posi 91 454 Edel Performer RPM Intake 750 cfm carb Comp Cam 268/.495 Hedman Headers Dual 3'' Exhaust 71 Cheyenne 20 4x4 Fact. A/C PS PB Tilt Currently in the works... Speak Softly and Carry A Big Block... There is No replacement for Displacement... "If everything seems under control, you're just not going fast enough." - Mario Andretti

01-06-2003, 11:46 PM	#2
HvyChevy454 Slowly getting CRSS... Join Date: Jul 2001 Location: Lutz, Florida Posts: 656	maybe i shoulda posted this on the trans board? __________________ -Nic Lutz, Fl My Team Website The Heavy Chevy Website ------------------ 72 Cheyenne 10 LWB GM 12-bolt 3.08 w/ Auburn Posi 91 454 Edel Performer RPM Intake 750 cfm carb Comp Cam 268/.495 Hedman Headers Dual 3'' Exhaust 71 Cheyenne 20 4x4 Fact. A/C PS PB Tilt Currently in the works... Speak Softly and Carry A Big Block... There is No replacement for Displacement... "If everything seems under control, you're just not going fast enough." - Mario Andretti

01-06-2003, 11:56 PM	#3
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	A short tail 400T is approx 11/16 longer than a short tail 350T. The slip yolks are a different size, & the trans crossmember locates in a different place. the converters will swap. TCI has case dimentions..... http://www.tciauto.com/tech_info/trans_dims.htm __________________ 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....

01-07-2003, 12:09 AM	#5
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	The tork converters are not the same, the 400 generally had a larger dia converter......they will swap as long as the 350 isnt a lock up trans,& & you have both patterns on the flexplates. I have run the smaller dia converters on the 400t(thats usually what you get with a mild aftermarket verter) __________________ 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....

01-07-2003, 12:27 AM	#6
HvyChevy454 Slowly getting CRSS... Join Date: Jul 2001 Location: Lutz, Florida Posts: 656	gracias crazy __________________ -Nic Lutz, Fl My Team Website The Heavy Chevy Website ------------------ 72 Cheyenne 10 LWB GM 12-bolt 3.08 w/ Auburn Posi 91 454 Edel Performer RPM Intake 750 cfm carb Comp Cam 268/.495 Hedman Headers Dual 3'' Exhaust 71 Cheyenne 20 4x4 Fact. A/C PS PB Tilt Currently in the works... Speak Softly and Carry A Big Block... There is No replacement for Displacement... "If everything seems under control, you're just not going fast enough." - Mario Andretti

01-07-2003, 12:38 AM	#7
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	you are welcome __________________ 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....

01-07-2003, 11:09 AM	#8
1971Stepside Almost Satisfied Join Date: Mar 2002 Location: Springfield, MO Posts: 2,932	I took my 400 to my transmission guy and he actually recommended putting the 350 torque converter in it rather than the 400. As crazy longhorn said, that gives you the extra performance.. __________________ 1971 C10 Stepside. LSx 6.0 with BTR Stage IV, Speed Engineering Headers, 4L80e transmission w/3200 Circle-D Stall. 3.73. Posi. Purchased this truck when I was 17. I started the rebuild (or take apart) in 1993. I have drug it around all over the country in pieces. Finally back on the road in 2021. "I can't complain, but sometimes I still do. Life's been good to me so far."

01-08-2003, 12:17 AM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Yup, I had to install a TH400 verter into my Th350 so I could run it behinde the caddy engine. The caddy only has TH400 holes drilled in the fly wheel. Crazy, you think this will hurt my theoretical stall? It's all stock, so it's not like I had alot of stall to lose there.

01-08-2003, 12:36 AM	#10
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	I dont think it will hurt you too much longhorn, with the larger cube eng, & the gears in that 1 ton. The 70 delta that I drove home (455 /2brl) had a 400 t with the large verter.......it would boil the hides at will! __________________ 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....

01-08-2003, 12:37 AM	#11
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	350 and 400 torque converter. Same thing. Sometimes the bolt patterns different. Sometimes its bigger in diameter depending on what vehicle it was under more than the type of tranny. __________________ No truck :-(

01-08-2003, 03:15 AM	#12
wxman1 Senior Member Join Date: May 2002 Location: mt juliet, tennessee, usa Posts: 237	Can somebody educate me on what a stall converter is and why its important? Jim Mt Juliet, TN

01-08-2003, 03:21 AM	#13
Project1970 14.1 @ 96MPH Join Date: Jul 2001 Location: Mesa, AZ Posts: 2,811	All converters are 'stall' converters - the difference is whether they stall at stock speed (roughly 1500RPM) or higher. More or less, the stall speed is where a torque converter really 'bites'. You only need to worry about it if you're running a hot engine that doesn't have a whole lot of bottom end, or doesn't like to idle much. A stock converter, you'll generally have a hard time holding the vehicle still if you try to get the RPMs above 1500 or so...the higher 'stall' a converter is advertised with, the higher RPM you can do before it'll really try to move. More or less...it's how guys with autos launch a vehicle at anything higher than 1800RPM. __________________ Project1970 - LS1 Swap Complete!

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