TH400 t/c on a TH350?

Moderator: Moderators

TH400 t/c on a TH350?

Postby sugaryuk » Sun Feb 14, 2016 3:53 am

I just noticed that the torque converter on my th350 is an ACC Boss Hog #46033---which is listed as a th400 t/c. Is there an advantage to running a 400 t/c on a th350? Original owner said tranny was built by a performance shop. I know that some run a 350 t/c on a 400 to get a higher stall, but I hadn't heard of them being swapped this way.
User avatar
sugaryuk
 
Posts: 141
Joined: Wed Mar 05, 2014 1:29 am
Location: Vancouver,BC


Re: TH400 t/c on a TH350?

Postby spencerforhire » Sun Feb 14, 2016 9:51 am

TH350 and TH400 both take the same converter. An OEM converter from a TH400(only originally available on high perf. and heavy duty v8 applications) might be a little tighter than one originally from in front of a light duty 4, 6 or small V8 TH350. Anything aftermarket would be meant for both.
And like the majority of drag race Powerglide transmissions, mine have been modified with aftermarket input shafts that let me use a TH350/400 converter.
The "fleet"-
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
03 Silverado 2WD ex.cab (work truck/parts hauler)
04 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
93 Suburban- 350/4L60(retired)
00 Saturn SW2- wife's car
01 Saturn SC2- younger son's project
00 Saturn SL2- daughter's car
98 Saturn SW2- spare
and 3 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
User avatar
spencerforhire
 
Posts: 2399
Joined: Mon Jul 03, 2006 9:02 pm
Location: Halifax, Nova Scotia

1972 Chevrolet Vega Hatchback

Re: TH400 t/c on a TH350?

Postby sugaryuk » Sun Feb 14, 2016 3:27 pm

Thanks for the reply Spencer! I thought they were interchangeable but just wanted to make sure. Still not sure why he chose the 400 t/c rather than the 350 t/c, same specs except outer bolt pattern size, maybe had it sitting around the shop?
User avatar
sugaryuk
 
Posts: 141
Joined: Wed Mar 05, 2014 1:29 am
Location: Vancouver,BC

Re: TH400 t/c on a TH350?

Postby spencerforhire » Sun Feb 14, 2016 8:45 pm

I forgot about the different bolt patterns; most GM and all aftermarket flexplates come with both sets of holes.
The "fleet"-
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
03 Silverado 2WD ex.cab (work truck/parts hauler)
04 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
93 Suburban- 350/4L60(retired)
00 Saturn SW2- wife's car
01 Saturn SC2- younger son's project
00 Saturn SL2- daughter's car
98 Saturn SW2- spare
and 3 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
User avatar
spencerforhire
 
Posts: 2399
Joined: Mon Jul 03, 2006 9:02 pm
Location: Halifax, Nova Scotia

1972 Chevrolet Vega Hatchback

Re: TH400 t/c on a TH350?

Postby bruceb » Wed Feb 17, 2016 12:44 pm

Usually an advantage in t/c is measured in higher stall speed. Stock t/c s are larger in diameter .Higher stall speed t/c s are usually smaller at 10,9,8 inches in diameter. Depending on flexplate bolt pattern , a 350th and 400th can use the same t/c.
bruceb
 
Posts: 12
Joined: Thu Jan 21, 2016 5:42 pm

Re: TH400 t/c on a TH350?

Postby spencerforhire » Wed Feb 17, 2016 6:47 pm

The 8" FTI converter in my drag car stalls at 5500 rpm on the trans brake behind the almost 600 hp 383. That's past the red line of the majority of SBC's in stock form. Back in the day, OEM 4 cyl Vega converters were highly sought after because they would stall 3000+ rpm behind a healthy SBC. Yeah, I have one on the shelf, but I wouldn't dream of trying it out. I suspect it would last maybe 2 or 3 passes.
The "fleet"-
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
03 Silverado 2WD ex.cab (work truck/parts hauler)
04 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
93 Suburban- 350/4L60(retired)
00 Saturn SW2- wife's car
01 Saturn SC2- younger son's project
00 Saturn SL2- daughter's car
98 Saturn SW2- spare
and 3 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
User avatar
spencerforhire
 
Posts: 2399
Joined: Mon Jul 03, 2006 9:02 pm
Location: Halifax, Nova Scotia

1972 Chevrolet Vega Hatchback


Return to Transmission and Driveline Tech

Who is online

Users browsing this forum: No registered users and 1 guest