351W Tuning

[Gun Doc]

It looks like the weather here in Texas may finally be changing and my new PE built 351W is broken in, so I guess it is time for me to attempt to fine tune my Weber set up.

The engine starts and runs well at idle and at almost any rpm while holding the throttle steady. My problems are manifest when first accelerating from a stop, or when passing on the hi-way where the engine runs extremely rich. So much so that my buddies kid me about having a second job as a mosquito fogger! You can really tell during around-town driving by the strong fuel odor that the engine is very rich, as well.

My engine in not too radical; it is a basic 351W with AFR 185 heads, 9:1 compression, 32deg timing, cam has mid 500s lift with around 244 duration 110 deg separation. It produces right around 460HP @ 5100RPM and 500lbs/ft @ 4000RPM. According to the dyno sheet from PE, has fuel/air ratios between 12.74 and 11.87 at speeds between 3000 and 6000RPM. The carbs currently have F7 E tubes, 145 mains, .120 low speed air bleed, .70 idle jets, and .120 high speed air bleeds. I am pretty sure the choke tubes are 37mm.

I recently bought the Weber tuning manual, a synchrometer and a set of .60 and .65 idle jets. Just out of curiosity, I checked the air flow on all of the barrels yesterday (with the main linkage disconnected) and got readings from 5 on the front left two barrels to 10 on the left rear barrels. The right hand bank of cylinders was not quite as bad, but still ranged from 7 up front to 10 in the rear. Of course these readings were with old plugs, which I am sure are at least partially fouled.

I am wondering what the collective wisdom of the Weber experts is…Should I start by reducing the idle jet size to the .65, change the plugs and sync the carbs, or do you all think a change in the E tubes is also in order? Or maybe there are other changes I should consider?

Thanks,

Gun Doc