I’m not an FED guy but this seems pretty basic. Sounds like your going to waste a bunch of money, then spend some more. First I would spend the money to put it on an engine dyno to find out what you have for power and torque. There is a big difference between running the motor in a 3000+ lb truck and a 1400 lb dragster. Initially, set the car up to run at it’s maximum potential, you are going run it there at some point in time. If your going to try to use the converter out of your truck, forget it, you won’t be happy. If you ran this motor on the street you are probably talking 10.5:1 compression and maybe 500 hp if it’s well prepped. Rpm wise it’s probably all done between 5800 and 6200. Now that you know what your engine can do you can set the car up to run at maximum potential, determine what maximum rpm the engine will run out the back door, lets say peak HP plus 1000 rpm,, from the number above that’s about 7200 rpm. Next look at tires, what is everyone running. Running a street engine you’ll be on the lower end of the power curve. You have a choice, select the tire based on what power you have or select one that suits your combination in the future. Now select the rear gear. Realize that different manufactures tires grow at different rates. For this exercise lets say the growth is 1.5 inches at 150 mph, add 3” to the diameter of your tire and calculate the circumference of your tire at speed. Manually calculate the rpm out the back door. A good 7” race converter is going slip about 2 ½-3% down track, that’s 250 rpm at speed, subtract that 250 rpm from the 7200 rpm and recompute the rear gear ratio at 6950 rpm. Time for low gear, the more power you have the less gear you need. Ask around, what gears are they running. To determine a 1st gear launch ratio ( 1st gear ratio x rear gear ratio example 1.96 x 4.11 = 8.05). If you have less power you will have to run more 1st gear, 2nd gear is whatever is available, if you have a choice probably the higher ratio. Don’t worry if its more than everyone else, its based on your power and you are only there for a second. Where to spend the money. Dyno 1st $500-$750, torque converter, you’ll need your dyno sheet for this $1000-$1500, if you can find a good core you can send it back and for about $500 they’ll rework it to your requirement. See if you can find a set of good used tires that will work $100-$300, Rear gears depending on what is in the car now, you can buy ring gear sets for around $150. Learn how to set up the rearend gears yourself. I don’t know about transmission gear sets but, probably about the same as ring rear sets. Become an expert on changing gears for your combination, its not that difficult. If you haven’t bought the alcohol setup, don’t until your ready to switch. Having said all this, race what you brung and use a rev limiter and chip it down. Just my $.02
