Re; My 304 stumble

[Doug Rasmussen <76075.2276@domain.elided>]

Tom Mandera wrote:
>Well, I'm in luck then.  I have a "brand new" (OK, bought in '96 new, but 
used for one year) Holley #7448 model 2300 350cfm "off-road only" carb on 
my 304.. supposedly one of the more adjustable 2bbl Holleys.

I have no idea which power valve is in the Scout now.. but I also have an 
off-road spring-loaded needle and seat to install, and some different jet 
sizes to try for better economy and/or power.. so I'll pull the power 
valve while I do all of this, and swap up for a larger one.

What's the downside, other than the EcoNazi's war cry, to a larger power 
valve?  Will fuel economy drop if I keep my foot out of it?  Naturally, 
when I floor it, economy would go down... ;)<

Tom,
  Your #7448 came with a 125-85 power valve and #61 jets.  You could switch
to a 125-185, "high flow" power valve.  Both open at 8.5" Hg.

  Or, quoting Holley, "Racers sometimes will prefer to run without a power
valve.  In these cases a power valve plug must be used to block the power
valve circuit.  Furthmore, jet sizes must be increased to compensate for
the loss of the fuel enrichment provided by the power valve.  An increase
of 6 to 8 jet sizes will, in most cases, be enough compensation. . . . ."  
 You are a racer, aren't you?

  This is interesting.  6 to 8 jet sizes compensate for no power valve.  I
have a 500 cfm "off-road only" Holley 4412 that came with #73 jets, 125-50
power valve, on my 304.   I get around 12-15+ mpg in my 3700# 800 with 3.73
gears.  Wonder what I'll get when I re-jet to something like #61 jets. 
Theoretically, I'm way over-carbed.  I could even get by without a power
valve (according to Holley,above).

  How about slightly bigger jets and a power valve opening at 3.5"Hg
(125-35).  that way you'd hardly ever open the power valve, but would have
plenty of gas from the bigger jets.  Mileage might drop, though.   Geez,
the possibilites are endless !

  BTW, did you know, several aftermarket companies sell externally
adjustable jet plate retrofits for your Holley?  I have a Percy retrofit,
but haven't put it on yet 'cause of clearance probs with the 800 thermostat
housing (needs at least 1" carb riser, maybe more).

Doug