69 SB Rochester Carb #207

[George D.]

I have a problem with the engine pinging on a hard pull at WOT. The timing etc. is OK. I would like to increase (make richer) the fuel mixture for the secondaries. Currently the secondary metering rods are coded BG (PT# 7034822). Can someone tell me what the next richer metering rod code and what the GM part number is?

Thanks,

[john38706]

Re: 69 SB Rochester Carb #207

bump your timing back till it stops pinging. what are you running for fuel?

[George D.]

Re: 69 SB Rochester Carb #207

I'm using 93 octane pump gas. The compression has been lower to 9.6 as well as a new cam was installed to offset the loss in HP. The timing is correct. That is to say it likes the current timing. It appears that the engine wants more fuel at WOT. I want to try to increase the amount of fuel to the secondaries to see if the pinging goes away. If it doesn't I will retard the timing.

Thanks,

[Clem Z.]

Re: 69 SB Rochester Carb #207

BG is a .040 tip. CF #7044775 .034 tip, BY #7040856 .032 tip, CC #7042356 .030 tip. edelbrock has CC under part # 1950 and any speed shop can get them for you