[bmarko26]

i recently removed a tired 307 and dropped in a fresh 350 in my 68 chevelle.i`m having a problem when bolting up the tranny (powerglide) to the engine ,when the bolts are tight the torque converter will not spin. i`ve had the motor out a couple times to check things but can`t pinpoint the problem.when first putting the engine in i was using flexplate for the 350 and had trouble getting the engine lined up to tranny and had trouble tightening the bolts so i removed the engine and swapped the flexplate from the 307 which is smaller. i then checked the converter and it would not spin, so i got it freed up and i`m pretty certain that it was in all the way so i put the engine back in and had no problems getting them together with the smaller flexplate .i got a several bolts in tight no problem and checked converter and it won`t spin so i loosened one bolt maybe a turn at the most and the converter spins .i then slid the tranny back on some longer bolts to keep it lined up and slid the converter forward but cant get the flanges for the bolts flush with the flex plate ,theres about a half inch gap . i`m stumped . any suggestions? could the nose of the converter be too long to sit inside the end of the crank on a 350 and not a 307? i don`t know . any help would be great. if i need to move this to a different forum let me know. thanks . bob

[bracketchev1221]

It sounds like the converter is not pushed all the way back into the pump. Look in the front seal and you will see the drive lugs for the pump. The converter should be about 1 1/2" back from the edge of the bellhousing if its engaged. I usually set the pump drive lugs up and down or side to side so know about where the converter should be to go in.

[bmarko26]

i`ll check that tomorrow after work .it sure felt like it was all the way in. it seems that even with the tranny slid back away from the block and i slide the converter forward to the flexplate the flanges on the converter don`t sit flat against the flexplate. i apologize for repeating .

[rwin1592]

Any chance you have a pilot bushing in the crank shaft (from a manual trans car). That bushing can prevent the torque converter from seating against the flex plate. Regarding getting the converter back into the trans far enough to pull the trans up to mounting position you must be certain it is fully seated into the pump. You should not be able to get your fingers between the torque converter and the transmission case. If you can, keep trying to turn the converter a little at a time while trying to push it back into the transmission. You'll eventually find the alignment slots and it will fall back the rest of the way into the front pump and allow ample room to bring the trans up against the engine. You should then have to pull the converter forward about a half inch to make contact with the bolt surface of the flex plate. As for one flex plate versus another, I am not sure if there is a difference. Sorry about that one. May want to consult an interchange guide. Good luck.

[bmarko26]

wow,i never thought of that, i guess there could be since all i know is that it came from 76 truck.makes sense now that you mention it .thanks so much,i`ll check it out after work on thursday and get back to you.bob

[BigBocks66SS]

Originally Posted by rwin1592

Any chance you have a pilot bushing in the crank shaft (from a manual trans car). That bushing can prevent the torque converter from seating against the flex plate. Regarding getting the converter back into the trans far enough to pull the trans up to mounting position you must be certain it is fully seated into the pump. You should not be able to get your fingers between the torque converter and the transmission case. If you can, keep trying to turn the converter a little at a time while trying to push it back into the transmission. You'll eventually find the alignment slots and it will fall back the rest of the way into the front pump and allow ample room to bring the trans up against the engine. You should then have to pull the converter forward about a half inch to make contact with the bolt surface of the flex plate. As for one flex plate versus another, I am not sure if there is a difference. Sorry about that one. May want to consult an interchange guide. Good luck.

Bob, you are correct, there is no difference other than diameter and teeth count. I suspect that there is a problem with the pilot not going into the crankshaft for some reason. Most Chevy cranks are double stepped in the pilot area so even if there is an old pilot bushing still in the crank, and it is seated far enough forward, then it shouldn't intefere with the larger pilot on the torque convertor. I would suggest to remove the transmission completley, and try to put just the torque convertor up against the flywheel, and see if the pilot will go up into the rear of the crankshaft, and the pads on the torque convertor sit flat with the mounting pads on the flywheel. The flywheel isn't on backwards is it? The raised portions of the mounting pads on the flywheel should be towards the torque convertor.

[Bowtie70ss]

If you draw the block together to the transmission with bolts rather than by just aligning everything you run a high risk of breaking the front pump. You will know because your trans won't work. There is no way you could have it all the way back if it is binding. If the torque converter is new or different make sure the ears that engage the pump aren't messed up. I always make sure the TC spins even while I tighten the bell housing bolts.

[bmarko26]

well i removed the tranny and found that the pump is indeed broken.i really thought it was in all the way.i have a th350 so in it goes .thanks for the input. bob

[Bowtie70ss]

Man, bummer I really hate to hear that. If you have to draw the engine and trans together just keep turning the converter so it does not get jammed. You are probably better off with the turbo 350 anyway.