Straight up as in "0".. I noticed a difference in a stock (but for header) 88 prelude with gears 4deg+ on the intake and 4deg- on the exhaust (that would be like filling the combustion more and separating the lobe angles on a SOHC)
again, nothing but the ol butt dyno and better mileage.
'Degreed' usually means that they setup the cams to open at the manufacturers settings for that particular "assembly line" engine. NOT for YOUR engine. That's where they should have messed with trying to extract as much as they could while they had it on there..
Isn't that what THEY are SUPPOSED to do? NOT just charge "these young kids for dyno time"
Heck, read any of the car mags where they take an engine from one of their "builds" and spend all day changing heads, cams, header(s), carbs/injectors, ignition...... Get the picture? That's why I'll never be able to pay for dyno time here in the Memphis area. Just for a Chevy 406 that I built, they told me that it would cost "about 500.00" that was about 10yrs ago, and with just a balanced .030-400 block and a set of Trickflow heads, Comp ex274 cam, Holley 750, Stealth intake and recurved dizzy.. Probably not changing anything but timing and jet sizes!! Hell, I can do that having it sit in my OWN car.
And by "p/p", do you mean port and polish?
Porting under the valve head always helps but in low lift cams (or stock)one usually doesn't see that much of a difference. (I'd doubt that in my Briggs/Stratton that it would gain 2%) It's when you take advantage of that porting with a aggressive cam grind and 'hogging' out the port, High comp, and high rpms is when the engine really comes alive. There is a reason that dyno's don't start reading the engine until over 2-2500 rpms, and why turbo'd apps start spooling at a certain level of exhaust flow.
So what are your cams at?
Are they Stock cams?
I don't mean to piss on ya.. But I'd bet you that there IS more in your engine and MPFI..
Heck I've seen gains in just changing to a good synthetic oil (Like Amsoil 0W30) after break-in.
Don't forget about the trans too! It's called "Intrafluid Friction" (trying to stir a bucket of dirt has more friction than a bucket of water) I could state more "fun" scenarios talking of lubrication, but I think You get the idea..
Sorry for the long post. It's just that it sounds close to a build that I'm gonna try and accomplish.
E