My 74 Challenger originally had a 318 and 904. It had sat untouched for over 9 years when i bought it, and a 360 LA engine came with it but uninstalled. The builder said it would have "at least 350+ HP and to use a 3000 rpm Torque Converter. Engine has in it the Mopar performance 508 camshaft. The 904 was supposedly in good condition when the car was parked and the fluid on the dipstick look clean (Speedometer shows 83,500 miles. . The rear end is still the original 8 3/4 2.71 open differential. I have a 3.23 suregrip to put in, but, havent done so yet. So, I bought a used TCI SuperStreetfighter Torque converter and bolted it all up. Engine is strong !!
The car seemed to run good and shift correctly although the 1-2 shift seemed to slip a little, and the tach showed a higher RPM at speed (60 mph) than I thought it would have with the 2.71 axle...i.e around 2500-2600 rpm (235x60x14) tires. The more I drove it the more slippage it seemed to have, to the point where now if I pull out and give more than say 1/2 throttle it completely slips and seems like almost neutral... Back off and you feel it grip again. Slippage is in all forward gears although high is the least. Also note that reverse is strong...no slippage..
I believe that probably both the front and rear clutches are worn out from the 83,000 miles, and sitting for 9 years, and then of course trying to handle the extra horsepower. I worry that maybe that used TorqueConverter is also slipping a lot and part of the problem??? That is one reason why i point out that in reverse there is no apparent slippage and it will easily light up a tire even with only a 2.71 rear axle.
Ok, believing it to be the 904 transmission front and rear clutches, I'm going to attempt to overhaul it myself. Looking for any recommendations for rebuild kit. Should I buy one with the Red Alto clutches?? Will it fit in correctly with those clutches or am I going to have clearance issues with them? Anything else to worry about??
