What are the more cost effective ways of increasing the performance of a 91 z28 w/5.7 and dual cats?

How much horsepower/torque should i expect from a set of slp headers and downpipes?

How much horsepower/torque should i expect from getting two high flow cats, such as random tech or catco.


How much horsepower/torque should i expect from an airfoil, high performance spark plug wires, and an adjustable fuel pressure regulator?


These are the things i feel i should start out with. It already has flowmaster muffler.

 

Headers & good cat-back= *AT LEAST* 25 RWHP..more like 30

High Flow cats= DITCH THEM MAN!!...if you have to have them...depending on the mileage and running condition of the car...I'd leave the stockers on there

Airfoil= approx 5 HP...prolly less

Wires= wont give you any *extra* HP but those along w/ a full tune-up will RESTORE HP..making you feel you picked up extra HP

regulator=good for gobs of torque!! maybee 10 HP or so. Ipicked up over 35 ftlbs of RWTQ on just tinkering w/ FP. running at 48 psi on my L98

 

Ive never had my car dynoed so I dont know what kind of numbers Im laying down, I wish I knew really. I have a 92 Z28 w/350 and added airfoil, crank pulley, flowmaster muffler, rebuilt tranny w/ 2k stall, converter and shift kit, alum DS, Catco cats, 8.8 wires, K&Ns and MAT relocated. With these "mods" and LCAs & SFCs I went 13.52 on drag radials in good weather. ill have times after SLP 1 3/4s and !AC in the beginning of March, and then with a TPIS base, port matched SLP runners and plenum and adj fuel reg and Ill see where that takes me, Ill post the times as I add the parts, hope this helped a lil....

 

Learn how to burn your own eprom, especially when your motor is still basically stock. Then you will get ALL the HP your setup is possible of delivering. Plus you will save moneyon gas by invoking Highway Mode.