transmission 700r4

best thing you can do is a torque converter and shift kit

i was thinking that i heard the 3000 to 3500 stall were pretty good ones any have some good exp with one of them?

How much power does the motor put out. A well-built 700r4 is good to about 350-400 HP. You have to spend big bucks on the 700 to go past that power level. Make sure you have the newer style transmission with the larger (30 spline) input shaft. Early 700's and transmissions from V6 cars have the smaller (27 spline) input shaft and will not live behind a torquey V8. If you have the 30 spline case, build it with a good set of clutches and steels (adding an additional clutch to the clutch packs with thinner steels is a VERY good idea) A Kevlar band will also help it live behind that V8. Use a corvette or aftermarket overdrive servo. Once you get it all together, I can tell you how to tune the shift points with the governor. A stock Corvette governor is a good place to start for most cars. DO NOT use the throttle valve cable (downshift cable) to set shift points. That is a guaranteed way to fry a new transmission. For a street car I recommend about a 2500 to 2800 stall speed converter WITH lockup. Many high-stall converters eliminate the lockup feature. This is great for drag racing, but the tranny will fry on the highway if you do not have a lock-up converter. I have a 2200 stall in my 700r4, and that is the only thing I regret. I wish I had gone a little higher on the stall speed. My 85 Monte Carlo is pretty heavy, so a few hundred more RPM stall speed would have helped it off the line a little. If you must have a non-lockup converter, (bad idea) make sure that the stall speed is LESS than the highway crusing RPM with your rear-end gear. If the converter stalls at or above cruise RPM and you cannot lock it, the converter slips all the time on the highway. That causes heat build up, and the tranny goes south. Overall, the 700r4 is a good "mild performance" transmission. Properly built, it will live a long and healthy life behind that 355. if you ever add nitrous or forced induction, you will need a TH 400 to handle extreme power levels.

How can u beef up a v6 to equal or almost equal to a v8

Supercharger. The only difference between the two is size. A 4.3 vortec is a 5.7 missing two cylinders. The 4.3 is a great engine but if you want to replace cubic inches you have to "stuff" more mixture into the cylinders and that is only done with a supercharger.