My86TransAm

Ok, I need to know if I can adjust the AFPR screw with the plenum on or off, I figure it'd have to be on so you can drive it and see if you notice any difference, right?
Also, do I make the reading with the vacuum hose on or off? ( its the 305, if that makes any difference)
Thanks guys!

P.S- Ok, so it was TWO questions...

bnoon

You'll want to dyno test each setting, or at least have some sort of wide band O2 readings to go from. Butt-dyno won't notice the few HP change in many cases. Either that, or do several passes down the quarter to set it...

You'll make the adjustments at idle with the vacuum line off because idle vacuum lowers the pressure during idle otherwise and you'd get false readings on your pressure gauge.

My86TransAm

Therein lies my problem, I dont have access to a dyno, theres only one here in utah and its $120 for three pulls. I was planning on put it all back together and going up in 2lb increment before I do a couple passes, put I need to know if I'm gonna have to disassemble it every time I got to adjust it.

Brian'sIROC

you won't have to disassemble it everytime. You may however need to make a custom wrench to fit in there. Here's what I suggest: Grind yourself some extra clearance on the plenum above the adjusting screw. If the screw is a standard hex head screw, replace it with a set-screw. This way you can grind down a small Allen key to fit in there and make adjusting easy.

Or just buy the Holley AFPR. It has a thumbwheel that makes adjusting a snap.