What power

[S&B]

345 peace

 

[1989DropTop]

way too many unknowns Upgraded fuel pump? stock cam (Are you kidding me) if your taking the time to swap heads out spending big bucks on AFR's with 58cc compression please take a few minutes and swa the cam. The stock Explore 4 bar GT40P heads have 59CC and cost a hell of alot less. Just a thought. 19#injectors? what intake?

I am going toi run GT40P's for heads, a measley E cam, for the most part stock bottom end, GT40 Upper Intake, 75MM Accufab throttle body, upgraded 4 hole injectors 19lb, 75mm mass air meter, just for starters. So far with bargin shopping this set up has run me under $400. Just my 2 cents

 

[90lxcoupe]

Dont bother, re-degree to 112, run a 1.72 rocker and you'll get the same thing

I disagree, and thought this technical post would help some of the stangnet guys

sweeping observations about camshafts (in of themselves) are rarely valid. Valve events are so dependent on the size of the door and displaced volume being drawn or pushed, that blanket assumptions are simply incorrect, or not wholly correct.

the stock 5.0 camshaft is quite small and the lobe separation is quite wide. Those characteristics are completely counterproductive in a restricted inlet motor. However, in a non-restrictive motor, for a given rpm, those are going to be the exact trends required by the valve events.

In a restrictive motor, retarding the camshaft (delaying the intake and exhaust lobes) can increase rpm because the intake closing is later. Hower, the intake opening is later as well, as is the all the exhaust activity.

What can happen is that the start of the filling process is delayed. When the motor needs all the help can get (in a restrictive inlet situation), the cylinder fill is diminished. SO what can happen is the motor spins higher, but the cylinder fill is non existent and the motor drops torque like a rock. Pair this up with delayed exhaust, the start of the inlet cycle might even be hampered even more by dirty inlet charge from the crosstalk with the residual exhaust.

On an unrestrictive motor, it can work the the other way. The motor will respond to the later intake opening because if it was opened too early, the port velocity is too low., etc etc

Can the small stock camshaft make usable power at 6500? sure, but it takes huge heads or a whole lot of inlet capability (forced induction). Will the stock 5.0L cam make usable power at 6500 in a stock or very near stock 5.0L (in reference to the heads and intake)? no.

I could go on for a long time, but basically I am just saying that blanket assumption on "cams" without any inclusion of the engine combination, simply do not apply. It takes all the puzzle pieces (or at least most of them) to see the big picture. A single pieces (or even a few pieces) could fit into many different pictures.

where advancing and retarding assumptions are correct is when the valve events are correct for the motor. Then small changes which alter the intake position will work as typically described, at least over a small window.

but if the valve events are completley wrong for the motor, the assumptions may end up being completely backwards.

 

[NIKwoaC]

Good post, Doc!

 

[98gtvert]

I stand corrected.

 

[Shaolin Crane]

Jeff im confused with your buddy rawls post. He says it will make power with good heads. Not reallt counter-active to what i said.

For the record, the cam tip i gave came directly from Ed Curtis when i asked him about a mild cam that would pass smog, make 450-500hp and be near stock driveable. He said that i could degree to 112 and save me about $350 on on of his custom grinds and the cam would act basically the same as an e303 or tfs stage 1.