I am new to posting but I have been reading these forums for about a year now. I recently bought a 1995 GT with a fresh 308. First thing I did was take it to the shop and have them throw some GT40 heads on it and an authentic 94/95 Cobra intake. It also has 70mm TB, 75mm MAF, Cold Air Intake, 24# injectors, E Cam, 1.6 Rollers,BBK Shorties, UPR O/R X Pipe, 255lph fuel pump, Kirban Adjustable FPR, Underdrive Pullies, MSD Coil, wires, cap/rotor, no smogpumpand 4.10's ( not that the gears help on HP). It dynoed at 271.49 HP and 307.36 Torque. These are the numbers right after it was all put together. I have an appointment for the 20th with Houston Motorsports to get a custom chip put in. I see others dyno numbers and mine just seem a little low. Will having the chip put in make more power or am I just expecting too much? I was hoping to make 300hp to the wheels. What else would need to be done tomake that goal? Any input is greatly appreciated. I hope to have some pics up soon and a vid of a nice smokey burnout.

Slightly low, not by much though. Did the shop upgrade the valve spring for the cam? Heads used? Stock springs? Your answer may be here.

Heads were used but fully rebuilt with new valves and springs. I was told they put in springs good to .600 lift.

sounds about right to me.

ORIGINAL: Fistuv

Heads were used but fully rebuilt with new valves and springs. I was told they put in springs good to .600 lift.


Good to .600" lift really doesn't mean crap. Spring rate is what needs to be matched to the cam. I am not saying they installed the wrong part (or the right one for that matter), what I am saying is, if they used the incorrect spring rate for the cam, there could be too much or too little spring pressure on the seat and open.

There is also one thing you need to keep in mind, dyno's don't tell you very much. Your 271hp on this dyno could be 300hp on another and 260hp on yet another. The true test is e.t.'s, if you're a competent driver.

I guess the biggest thing is, Are you happy with how it feels? If you are, don't get wrapped around the axle about a dyno number.

I am very happy with it. Sounds like I should hit the track soon!

You almost have a Cobra set-up so your numbers are right on

Looks good to me:).

275 was my estimate as I read on....your close to 300Hp, so it won't be a problem to get there.

that sounds right on you should be fine. now go to the track with some stickies and run her see what you can do

sounds about right..don't expect to much more out of a gt-40 set up with an e-cam:D

have the heads been worked on at all? if not then that seems about right, to get to 300 with gt40's they need to be ported and all that. a tune should get you closer though.

Your power is right on...if you want more...NA...with your current set up...probably should have had heads ported...those headswork great with work.....and a custom cam...probably would have hit 300 mark....or very close....

Since you already back together above option is kinda lame to take it back apart...so if you want more I would wait on the tune....and get it tuned when you add some sort of power adder. NOS/Supercharger etc.....

a have a smiliar setup...add a 100 shot.....dry kit....its safe and get car tuned then...on the gas. That'll be fun.....

Auto or stick?

Stick