The weak link
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The weak link
Hi everyone, kinda new to this site. Seems there's lots of good info without all the arguing here so here's my first question-Just bought a 72 ford f-250 truck with 390, 4 speed, 4x4, 4.10 gears. It has a mild Lunadi cam, Edel performer manifold and Edel 4 bbl carb(dont know cfm on carb). Had a miss when I picked it up, 2 cylinders had no compression do to valve seats ground to deep so for now we shimmed rocker shaft since they are not adjustable. It also has low comp pistons(9-1). Im going to pull motor and do higher comp pistons and get a Crane cam with adjustable lifters, rpm manifold and Holly 3310 carb and headers.
I'll be doing some of the local mud races with 36" tires, since I've never raced one of these trucks before I was wondering how much HP the stock drivetrain can handle and how many rpms this motor is good for without gernading. I dont know what gear I should run it in the mud run, It tachs at 2200 at 55 mph.
Thanks, need help.
I'll be doing some of the local mud races with 36" tires, since I've never raced one of these trucks before I was wondering how much HP the stock drivetrain can handle and how many rpms this motor is good for without gernading. I dont know what gear I should run it in the mud run, It tachs at 2200 at 55 mph.
Thanks, need help.
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Joined: Aug 2001
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From: Evanston, WY
Originally Posted by splittinhairs
I was wondering how much HP the stock drivetrain can handle and how many rpms this motor is good for without gernading. I dont know what gear I should run it in the mud run, It tachs at 2200 at 55 mph.
Thanks, need help.
Thanks, need help.
With stock rods, 5500-6000 rpm should be fine for the engine.
In the drivetrain, I'm not sure which transfer case came in 72, so I can't say if it is strong or not, but I'll bet you have a dana 44 front axle, which will be your weak link at high rpm in the mud with 36's.
I would be amazed if you could pull 3rd gear with the combo you are describing, so you will probably be racing in 2nd. Simply put, you will be racing in the highest gear you can, to create as much wheel speed as you can. You will find your correct gear on your very first run. If it bogs in 3rd, then you will be racing in 2nd.
-Scouder
