Hey all, I'll make this short and sweet. I have a modified 305 TPI which is nestled in my 1992 Firebird Formula WS6. I've done the whole exhaust, thermostat, chip, air foil, Filter, going cold air, working for a re-built tranny, Looking into new rear gears around 3.43 or so, and adding more soon. What I need to know is what would be a great cam for my car. My application is mainly street, actually just about all street. I don't want some massive Torque oriented cam for drag applications, but I want more ***** then my stock one. I have the lower grade stock cam, my redline starts at 4.5k. I head the ZZ4 hotcam, I've also heard about LT4 hotcams...What is the application and which would apply to me..and are there others I should know about?

Thanks all

 

Your list of modifications does not indicate anything that would change the nature of the engine significantly. Exhaust modifications generally help, but frequently don't change the RPM range in which the engine produced maximum torque. Unless you are changing the induction system, the engine will still tend to make peak torque and power from 2,500-4,000 RPM, and fall off to stagnation at around 4,500-4,800 RPM.

Because of that, you'll want to maintain a cam profile with a relatively short duration, and aggressive ramps to promote most effective cylinder charging at those lower RPMs. The ZZ4 cam doesn't really fit that mold. The LT1 cams (all six of them) may or may not be appropriate, depending upon which cam you select. You would likely have better results with an aftermarket roller, such as a Comp Cams 08-302-8 or 08-304-8. Those are commonly known as the 264HR and 266HR profiles. Depending upon how much more programming you want to do, either of those can work well:

http://www.compcams.com/catalog/082_083.html


Of course, any improvement in cam profile will work much better with improved valve springs. The factory springs, even when new, are weak enough to allow valve float as low as 4,400 RPM. Install teh springs recommended with the cam, and the system will work at its best.

Increasing the rear gear ratio will increase the average RPM of your engine at all speeds, so better springs are imperative.

 

Wow Thanks for the good info and no I'm not changing my induction system just yet. I don't have the money for that right now. So basically if I were to look into a cam like that, with short duration and aggressive ramps, would I lose much top end? I am looking for more power in low end but not so much as to lose my freeway ability. But basically you're saying the TPI system has its power from 2500 to 4000 and the other cams won't help me much in that range? Its all confusing to me at times because I don't fully understand the numbers for cams. I know what they are, the lift duration that stuff, but I don't quite know what the numbers mean. Thanks though for the good info. I'll look into those cams a bit

Cheers