NavyCPO Posted July 18, 2023 Share Posted July 18, 2023 OK, so my car has a TH 350 short tail shaft in it and it is working fine. But I have on my shop floor what I believe to be a good TH 400 with short tail shaft. Does anyone know what the difference is in the length of these two transmissions or the difference in the length of the driveshaft for a TH 350 vs TH 400 car? I'm wondering if I'm going to have to get another driveshaft or if I can get away with just using a 1350 conversion U-joint on the front? I know one of you have done this conversion before, what are the challenges? Also, this transmission also has a TQ Converter in it and I think it may be a Stall Converter. The motor and transmission came out of an old chevy truck and my friend bought it for his C50 Dump truck. He ran the motor for a little while, (this is where the story part comes in, I told you, I almost always have a story! lol) but the motor blew up and obliterated the block and he obviously never used the TH400 in the C50. He sold me the dump truck, and he gave me the blown motor and the transmission, the TQ converter and rear yolk for the tranny, a spare flywheel, and 2 Edelbrock carburetors (an 850 and a 600) and an Edelbrock Intake. I salvaged a lot of good parts from the motor, 7 good pistons and rods, fuel pump, oil pump (melling M55), and the heads had the 2.02/1.6 valves I'm going to use in my new heads, guide plates, screw in studs, etc. This TQ Converter is a 10 inch and the ears are sticking out from the main section of the converter. I'm thinking that indicates it is a stall converter because most factory stock converters are 11-12 inches and the flywheel mounting ears are on the main body. My experience has been that TQ Converters usually don't have any markings on them and if they do they don't tell you important data like this is a 2500 RPM stall converter etc. This one does have what looks like an Item# 47012 on it, but who knows what that means? Does anybody have any knowledge on how I can tell if this is a stall converter or not and if so what stall speed it most likely would be? Can a transmission shop tell you? My Cam wants a 3000RPM stall and gears and I'm wondering if I can save the cost of a new converter if this one is already a stall converter. Any insight would be appreciated Quote Link to comment Share on other sites More sharing options...
NavyCPO Posted July 18, 2023 Author Share Posted July 18, 2023 Well I may have found the answer to the question about TQ Converter. 47012 comes up as a Boss Hog Night Stalker 2200-2800 Stall Converter on Summit Racing page. But the one pictured does not show the extended ears, but there may be different variations of the 47012???? The Boss Hog 47012 says it is a 12" Core though???? It says only for TH350 but it was in my TH400 and besides I thought that TH350 and TH400 use the same TQ Converter, because there are a ton of them listed that show they will fit both! Continuing to research this Pn.......... 1 Quote Link to comment Share on other sites More sharing options...
cbolt Posted July 18, 2023 Share Posted July 18, 2023 You can certainly call Summit and they will answer your questions about the extended ears. Could be a variation depending on application. 1 Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted July 18, 2023 Share Posted July 18, 2023 Th350 and th400 converters interchange. The extended ears were probably welded on for the th400 flexplate bolt pattern. Most likely the core was a th350 core. MOST flexplates now have the "big" and "small" torque converter bolt patterns. Back in the late 60's early 70's it was not uncommon to find only 1 converter pattern on the flexplate. The th400 is longer than the th350. I don't remember exactly but roughly 2" longer. So a shorter driveshaft is recommended. Torque converters will "stall" at different rpms depending on the engine. A 2500 stall may stall at 2500 behind a 350 but stall at 3200 or so behind a big block. 5 Quote Link to comment Share on other sites More sharing options...
Martin Todd Posted September 26, 2023 Share Posted September 26, 2023 How do you get that yoke out of the transmission. Mine is bolted on, I took the bolt off and tried whacking it out with a hammer, won't budge. Quote Link to comment Share on other sites More sharing options...
Dtret Posted September 26, 2023 Share Posted September 26, 2023 The rear yoke should slide right off with the driveshaft. Pictures might be needed. Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted September 26, 2023 Share Posted September 26, 2023 The bolt in yolk was used in heavy duty applications. Delivery vans (p30s), some tow trucks, flat beds etc. After unbolted, it should slide out. Sounds to be stuck, hit it a little more. There is an o-ring on the tailshaft that probably hardened like a rock. 1 Quote Link to comment Share on other sites More sharing options...
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