I have an 88 305 tbi auto with 108k miles. I flipped the air cleaner lid upside down, fit a taller air filter in there, and cut the exhaust with a sawzall right before the cat. Performance wise, I noticed that I lost almost all low end torque, but it rips harder than ever from 4k all the way up to 6k. Question is, how long can I keep revving it to 6k before I blow up? Also, is it just my butt dyno or did I actually increase air flow, change the power band, and possibly increase power? Without a tune, would any of that be possible?

 

a stock 305 with over 100,000 miles . spun up to 6000 RPM ?? experience tells me not very long . and you probably did increase air flow just a bit . i wouldnt suspect you made any more power than before . you just moved the power band a bit