new..

[bone collector]

welcome to the group, your stock engine is plenty powerfull, regear the axles, upgrade the exhast, air filter setup, maybe underdrive pullys. To get much better you would need a diffrent cam, larger injectors, reflash the ECM.
broncomatt

I own a 90 also but when I was lookin for a bronco I knew i needed the 351 so thats what I got are the 302s speed density like mine if so would the ecm flash be worth it cratchhe: as far as the timeing running you hot I wouldnt think so just dont over due it you will propbley need to run 93 octane if you do. Ive heard ups and down on the underdrive pulleys some say they didnt let the chargeing system charge enough I had the on a mustang and never had any problems. Ive always heard you can feel the diff on a electric fan swap :rebel: