Hi guys. I just found this thread and, in the interest of time, have not read all the details... But to answer the original question about the trans fluid going to the radiator, consider this: My coupe is the fourth car I have built using a TH 350 transmission running with NO COOLER! I simply took a 60 inch steel line and wrapped it around a piece of 2 1/2" tubing to make a coil and screwed it onto the transmission. It fits up next to the trans and requires no lines, flexible fittings, etc.

Some early Powerglides had no coolers; they had big holes in the bellhousing to enhance air flow. I had an old transmission mechanic tell me years ago that on lightweight vehicles, the difference between running a cooler and not running a cooler was about 30% shorter life of the fluid. He said I simply needed to keep an eye on the trans fluid and change it when it started to show signs of darkening or beginning to smell the slightest bit burned. I have had my coupe on the road since March of 2005 and probably put about 20,000 miles on it; it is just now showing signs of the fluid turning from red to brown...

So, do I recommend doing this? It's up to you. If you have room for a cooler, use one; I didn't have room under the car and didn't want to put one in front of the radiator. If you have a heavy vehicle (over 3,000 lbs.), or if you are drag racing or towing a trailer, etc, run one. My coupe is 2600 + pounds. the other 3 cars I did this way were in the 2400 pound or less range. All of them are still on the road...