Many on this board know me as the nut who drove from california for the first BPG race in Salem, with acouple of stops in norwalk for good measure. My car has a 9 to 1, small cam 455 with ported heads, nothing fancy.about 4100 lbs with me in the drivers seat. 3.90 gears in a 9 inch ford, with a detroit locker. I have used the original TH350, rebuilt with a hardened input shaft and 2nd drum/sprag race, shift kit and either a 10 inch 3000 stall converter or the 11 inch 1800 converter that was in the car when I drove it to Ohio. Trans has always worked well, both converters worked well, car returned a high of 16 mpg on that cross country trip, usually returns 11-12 mpg local driving, so slippage in converter and trans are not indicated. My car has always been kind of lazy at the starting line, even with the 10 inch 3k stall, but tractionwas rarely a problem and even though it seemed the car should be faster than 13 teens to 13 40s depending on elevation and weather, it worked well so I didnt lose any sleep over ow much faster it should be. I purchased a SP TH400 from board member Rob Ross last spring, from his pure stock car as he was going to a fixed stator trans so he could use a 9 inch converter. Just finished swapping the transmissions this week and drove my car with the new combo. NOW MY QUESTION-this thing is unbelieveable!! what possible difference could there be internally in these 2 transmissions, to make the car behave like a stick leaving at 7000 rpm? the brake torque stall in high switch position is about 2600 with my mild engine and the low stall about 1400-but -the car launches like a missle, albeit a missle with sudden traction problems it has never had! I am amazed at the difference in the cars behavior at launch, and dumbfounded as to what to attribute it to. I beleive the low gear is the stock 2.48 in the new trans, and the sp converter does feel tighter than the other converters in the th350, no other seat of the pants things jump out. anyone? not unhappy, of course, and cant wait to get to the track to start sorting out the chassis again, I think there are finally some 12's with this low compression combo just around the corner, just curious. :3gears: :3gears: :3gears:
