ok what i need is a special plate that allows me to bolt my torque arm to the th350 tail and it bolts to the trans between the tail housing and the trans

i cant find them but i know someone sells them as i have seen them on camaros but no one ever remebers where they got them from

 

Sorry, still doesn't make sense to me. I understand you got the 350 cheap, etc. But it would make a heck of a lot more sense and would save you so much time and effort and probobly $ too if you just sold the 350 and put that money to the rebuild of the 700r4. I just don't see how that 350 will be a better trans for that car.

 

Overdrive is the best way to go, for both lower first gear, and lower rpm's on the highway. If you're not concerned with the highway speeds, then I understand why you want to do what you're asking, considering you already have the T350.
This is what you need: http://www.summitracing.com/parts/HUU-5500001/
In addition, you'll need a longer driveshaft and I believe a different slip yoke. Plus you'll have to revamp your shifter, and linkage.

 

no you are right the turbo 350 has the same splines as the 700r4 and with the 9in tailshaft housing you get the spacer block that bolts your 6in 700r4 housing to the 350