Tranny swap: TH350 to 700R4

[86SilveradoEric]

A friend of mine is in the process of tearing down and replacing everything from his stock '89 Formula to higher performance.  He asked me this morning if I'd be interested in the 700R4 transmission from it for my truck.  I still have the factory TH350, with 106K miles on it.  Its slipping a bit in first gear and does other weird things, so I'm sure I'll need a new one sometime.  His offer appeals to me, because he said he'll take just $150 for it!

My question is: Will it be a direct bolt up or will the difference in the engines(89 Formula 305//86 Chevy P.U. 305)cause any line-up problems?

I know these trucks came equipped with 700R4 transmissions, but I'm not sure if they changed in just three years from '86-'89, or if even the Pontiac trans/305 might be different from a GM truck trans/305.  

Thanks in advance, guys.

1986 Chevrolet Silverado Pickup

[problazer]

Bolt up is the same and you can use your tranny cooler and cross member. But ya have driveline issues.If I remember correctly the 700 r is longer than the 350 (depending on which one ya got). But you also need to find out if the Pontiac has a lock up torque converter or not. If it is not a lock up then you are good to go.
 
Great idea on the one piece glass by the way. I have been trying to get the same thing figured out for about 7 years now. I have seen it a couple of times but the company that used to make the glass went out of business.   Good luck, James

[86SilveradoEric]

Just curious...what if it is a lockup?  What problems will I have then?

And about the one-peice glass...I emailed a guy last night to see how he's coming along on it.  I contacted him a good while ago asking if he had one for 73-87 models(he was selling one for 67-72) and he said he was looking for a good price on the glass.  I'm thinking of emailing him again to see if I could get all the other parts, and have someone locally cut the glass.  I JUST ABSOLUTELY HATE MY VENT WINDOWS!!!!

1986 Chevrolet Silverado Pickup

[ratblock]

The lock up realy isnt a problem you can buy a kit from either B&M or TCI to control the lock up or you can even hook it to a toggle switch.

77 swb 468 4l80e np205 d60f 14bolt rear
71 blazer 383 th350 np205 d44hd front d60 rear  

[79chevyc20]

Would the lockup with a kit on a switch even be beneficial for towing? I know summit has a wiring kit for the 700R4. I am looking to do the same kind of swap, and would be doing a lot of towing, would I have to flip the switch every time it hit overdrive?

[ratblock]

Yes it would be denificial for towing to reduce transmission fluid temperatures.Plus you can use it in drive to not just overdrive.  

77 swb 468 4l80e np205 d60f 14bolt rear
71 blazer 383 th350 np205 d44hd front d60 rear