AFR readings

[moparstud440]

I did some index racing on Saturday so I had to unhook the 4bbl to get the car to run the desired ET. On Sunday was our normal bracket racing. With the secondaries unhooked my AFR was 12.3 at WOT, with the secondaries hooked up the AFR was 12.7 at WOT. Both days weather was fairly close, but was a little hotter on Sunday. I figured unhooking the secondaries would make it run leaner not richer. I've never messed with running on a just the front 2 bbl before so does that mean my front jetting is to big?

 

[MOPAROFFICIAL]

Pvr maybe, just look at how the front is setup from the rear or "4 brl"

Are you switching to a 2brl from a 4 brl , because its worded like you unhooked the secondary and throttle lever. Lol

 

[Brooks James]

Big guess, closing off the secondary
May have caused the carb to draw
Additional fuel from the idle and enrichment circuits

 

[moparstud440]

Pvr maybe, just look at how the front is setup from the rear or "4 brl"

Are you switching to a 2brl from a 4 brl , because its worded like you unhooked the secondary and throttle lever. Lol

Carb is a Proform 850 with no power valves. Ran same carb, just unhooked/removed the rod for the secondary and ran the carb on the front 2 bbls.

 

[MOPAROFFICIAL]

It's the heat.
It's so small, the heat is less dense air...so it would/could be rich that day while spot on the previous.
It could be leaner, yes, for economy.
For et? You'll have to test that out now.
Change 2 sizes smaller on the primary if you want to venture down that path and find out...
Or jet down till its lean surging at cruises then go up 2 sizes and test at the track.
Might find some power, may lose some.