I have a slightly modified 89 F150 302 V8, its got K&N intake, Throttle body, Jet chip, and I just bought a set of Flowtech full length headers and a set of 2 chambered design header mufflers.. Im wanting to know if I'll be ok running the headers instead of the stock manifolds and cats with just a glasspack, which I have right now. Will I notice and increase in power? Torque etc...? If anyone can give me some good advice and if they had any good or bad experiences please let me know... I also have heard about people breaking off bolts as they were trying to remove the stock manifolds, so if anyone knows a way I can avoid that or fix it if it does happen let me know... Any and all help is appreciated.
Thanks

 

use penetrating lube on the bolts for a couple weeks prior to the removal...

most people see an improvement in power and torque with long tube headers while only noticing a change in exhaust note with shorties.

also I would reconsider the glasspack with long tubes as it may be too raspy