90 k5 new mods,down on power

[bluboti]

Have 90 k5 5.7,86,000 miles,3.73 stock except 32x11.50,open element 14",force2 cat back.The new tire size seems to have really hurt performance.The trans wants to shift before powerband is reached.This may be part of problem.Is the ECM playing a role in the lack of pep?

 

[Bubba Ray Boudreaux]

Fuel filter? I run 33's on 3.73 and have plenty of power.

 

[Thunder]

Yeah my 89 with 3.73 and 33" tires lacks no power either.
If your trans is shifting improperly try adjusting the TV cable.
Maby a tune up would help too

 

[bluboti]

Yeah engines smooth no misses,new plugs,filter etc.I have a 77k5 350,3.08,33"tires it has a noticable bit of more umph.