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TH350 gap between converter and flexplate QUESTION

7K views 6 replies 6 participants last post by  oklowride 
#1 ·
I have a 350ci motor 350 from a 72 car and a th350 from a 85 camero. The converter is from the 85 camero and the flex plate is from the 72 car. I installed the converter on the transmission and then mounted the th350 to the motor. When I got under the car to bolt the converter to the flex plate there was a 1/2 inch gap between the converter and plate. I made sure that the converter was 1" from the mounting surface of the trans. Do I need a different converter? Do I have the wrong flex plate? Any help would be greatly appreciated!

BTW the camero the the th350 came from was a 305 motor not a 350.

Chris
 
#5 ·
humm

i agree its good to have a converter that is NOT tight against the flexplate during the installation process.. however after the tranny case is tight i measure the distance from the flexplate to the converter. according to my papers normal movement is 1/8th inch (sounds tight to me) anyways thats the minimum clearance. some of my papers even go as far as to say that if the clearance is larger than a 1/8th inch you should use shims to make up for it. i believe this is so their is maximum contact with the tyranny's pump but i am not sure. however do not make it tighter than 1/8 inch...

some other general tips:

flex plate lateral run out (measured at mounting holes) should be no more than .025

crank endplay should not be more than .010, clean the pilot hole to while your at it and add some grease.

make sure the dowel pins are not shoved in to far or missing.

this is what i have always done, seams to work good.

-Leo-
 
#7 ·
i installed a rebuilt th350 in a 75 truck that i rarely used over a year maybe about 20k miles and it shattered the planetary gear(into 10 pieces) in the pump i belive this may have been from this same problem. i dont remember haveing so much clearance when removing the old one but the new one did have about a half inch between the TC and FLY once i removed the trans the TC had some serious rash on it and i could tell it wasnt fully engaged to the pump gears. the work truck i have now i rebuilt the trans and upon removal i noticed it had 2 washers inbetween the TC and FLY. so my unprofessional yet experienced opinion would be to use a spacer or washer to get about 1/8 from bottoming in the pump.
 
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