need help tuning my carbed Ford 351W

[mnmike]

Here's the logs: http://66.41.218.133/cobra/june2005.html

I just started tuning and have some questions.

(mostly relevant) background:
1974 Ford 351W engine (reconditioned crank and rods, rotating assembly balanced)
keith black pistons
edelbrock performer RPM cam, heads, and intake
MSD6AL with blaster 2 coil
Holley 4150 double pumper with mech 2ndaries
primary jets are at 69. I replaced the stock 71 jets before I started tuning because I thought it was running way rich based on the fuel smell in my clothes every time I drive the car.
not sure where secondary jets are as I haven't pulled the bowl yet.
O2 in the end of the sidepipe using the innovate bracket.
No cats, 4 into 4 headers with mostly blown out glasspacks.
The car is a 2300 lb Factory Five cobra replica.

tuned for max vacuum at idle of around 900 RPM, which turned out to be way rich. (like 19.5)
timing set at 34 degrees at 3000RPMs. not sure where the idle timing fell.

I richened up the idle, but it started missing and running like crud, and the vacuum went out the window, so I set back to max vacuum and put the logs on this webpage in hopes of getting tuning tips.

cruising under not much load gives AF readings in the 14.5:1 - 15:1 range.
WOT in third will take the AF ratio to 11.5:1. the car idles fine and runs great.

1) Should I be concerned at such a lean idle reading? It seems to run fine there. All four idle screws are 3/4 turn out from full in.
2) where should I start tuning?

Sorry for the long post and the open ended questions...

Thanks,
Mike (first post!!!)

[klatinn]

Hi Mike,

Welcome to the forum.
Your lean idle readings or probably due to free air contamination, either by high exh. pulses or because you have a cam with high overlap. High overlap cams allow unburned mixture into the exhaust during overlap.
Different to what most people believe, running lean does NOT hurt an engine at idle or part throttle. Does not even hurt at WOT if you are running way leaner than stoich. Does not make much power though. Running lean (at WOT) is dangerous in the range between about 13.5 and 16 on a n/a car. The CHT's typically peak at about 14 AFR for gasoline and EGTs peak at about 14.7. But in low load conditions the temps don't rise very high (not enough energy) and the engine can't knock (not enough mixture density).

Regards,
Klaus

[mnmike]

Thanks for the advice Klaus!

I really appreciate it!

So at WOT I should make sure that my AF ratio is below 13.5?

If the weather's nice this weekend I'll try and get some WOT logs and see where they're at.

thanks again,

Mike