loss of power

[hammerhead]

I have a 84 bll with a 94 4.0 ohv we put in a new cam (delta cam Bp 568-I) port and polished heads k&n air filter New fuel inj. Pacesetter headers.rest of the motor is stock.did not touch computer. Use the truck for mud bog racing.it idles at 700rpm with no problems fuel pressure is 45psi. The trk takes off fine from the line goes about 50ft and loses power for a second and then runs wide open then dies again my foot is on the floor the whole time. It will die 5-6Times in a 200ft run. I'm thinking tps or it needs a chip.if it's a chip what do you recommend.thanks for any and all help