We know that stock transmission line pressure is not enough at 1500 RPM to avoid slipping (destroying) the tranny if full engine torque is called upon. Remember that peak torque occurs at 1500 RPM. Drivers who don't keep their RPM above 1700-1800 when making good power and torque (burning a lot of fuel) are the number one reason for the bad reputation of this transmission and failures. How does this apply to you? You want to turn up the power. A #10 plate, 3kGSK, timing, and 4 inch will give you a nice increase, probably to the 230 HP you want. But this increase will cause the tranny to slip under lockup and pulling a load just as mine did, even at higher RPMs. You need a better tranny.

Some will tell you to throw in some upgrade parts. Some have had good luck doing this, most have not. Most have had to pull the tranny multiple times to get it right. Some never get it right. A complete off-the-shelf replacement transmission ENGINEERED for your application is the best, not cheapest, way to go.

 

ok so this rig has less power than an fl 70 stock ctd. looks like 160hp. how bout like 190 woud that be feasable? thats what these gas trucks i work on say on the tag and they have good zip.

 

Like rare1 says you need to have some more line pressure as your hp increases and the happy spot is i would say 17-1900 rpm that will also give you the best fuel mileage. If you don't get too wild with the hp and you have a tranny that is in decent shape with the little easy mods drive it sensibly and you should be good. The governor springs will extend your useable rpm range. If you add a little fuel and get up around 190-215hp and use a lock up switch i think you would like it. The tranny's are not that bad at the lower power levels and a 47rh in the 94-95's are really just a 727 with an overdrive hung on the back .When you get into a 47 re thats when things get a little more complicated with electronics. Another thing you should do is bump up your timing i run at 17 but anywhere in the 15-17 range will do good the more you advance it the less bottom end you will have but when you put together this with some added power/fuel the overall driveability is much nicer.

 

so what is involved in a lock up switch and would i leave it on at all times at lower rpms? also you mentioned governor springs? what does a guy do with those and what would good replacement number ones be? also what would a good route be to add a little fuel?starwheel or fuel plate adjustment? sorry to sound so dumb but i just haven't messed with these much. mostly used to amc and chevy engines.