full throttle pinging....., wondering...???? Options

[crash914]

Ok, When ever I go full throttle, I get a lot of pinging....

in first or second, I can full throttle, but have to shift fast to the quick revs.

under part throttle, I can spin up to 6500+ with no pinging or problems. I just can't floor it.

seems odd to me.

my afr is down around 11:1 at full throttle, so I am running plenty rich. I am running 93 octane, might have to add some xylene.

I am wondering if my throttle bodies are too large. I don't know if my air fuel meter can pick it up that quick.

I really notice it when I am in 5th gear and am pulling from around 2500 to 6500.

I do have a spare set of heads that I can get cut...

all right here is the specs...103 by 80. .125inch barrel shims gives me around .1" clearance and around 9.7 to 1.

megasquirted with twin weber throttle bodies and large injectors...

herb

[john rogers]

What do the plugs look like after a full throttle run. When we put my race car on the dyno we used new plugs and pulled them after the first set of pulls to see the heat range. A/F was about 11.5 to 1 but they were a tad too hot so we went to a colder plug and the engine is happier. Not to confuse things too much but we found with 100 octane unleaded that we had NOT enough advance and the race fuels people said to run about 4 degrees more and when we did this head temps came down about 75 degrees. Seems we were buring the gas too late at high RPMs and it was really burning down the exhaust pipes! Oh yea, picked up 20 HP too when we were finally finished!