Oldsmobility85

iTrader: (1)

I have a holley 1000 and a qf850. Both of them mounted to my 406sbc are very rich on a cruise even though my idle af are perfect 14.0s and wot af is 12.9.
Ever since I have went to a glide with a 5000 converter it has been this way.
I feel the problem is probably in the size of the emulsion tubes in the metering block seeing how airbleed changes seem to have no effect.
Anyone have any useful info on how to lean this thing up?

Paul57

Is your powervalve opening during cruise??

speedtigger

iTrader: (16)

Make sure your powervalve is good like Paul suggested. Once you are sure that it is, you can drill your PVCR(Power Valve Control Restrictor ~ I think that what that stands for lol).

On my carburetor, I jetted up significantly for a good WOT AFR. This caused my cruise AFR to be very rich (approx 12.5). So, I drilled my primary PVCR from .040" to about .051", then jetted the primaries down 4 sizes. This gave me a cruise of just over 14:1 while maintaining my WOT AFR ratio of 12.8:1.

Oldsmobility85

iTrader: (1)

Yes its good. I tried the 6.5pv and a 4.5pv and it made no effect.
your saying that if I jetted down the primary main jets and that helps I could get the afr up by opening the fuel cirquit of the power valve. Makes good sense.

speedtigger

iTrader: (16)

Yes. At low speeds above idle, the idle circuit has a big influence over the cruise AFR. As the cruise speeds increase like 2500 and above, the main jet has the most control of the cruise AFR.

xpndbl3

iTrader: (23)

power valve channel restrictor.


on a quick fuel it will be drilled/tapped and you can buy larger sizes direct from them to jet down the primaries but still keep the same WOT a/f ratio. Hope this helps

Oldsmobility85

iTrader: (1)

Yeah this should help a lot. I am not sure why I didn't think of this but glad you guys did. I appreciate your time.

I will let you guys know how it turns out.