[jwinkler]

The motor's actually in a 1960 T-bird - I had the opportunity to spend a few hours driving it yesterday, and noticed what appears to be throttle-induced knocking.

I'm the guy who has the fire-breathing-but-but-from-the-wrong-end 351W in my CR, and in trying to figure that problem out learned that it's an excessively lean mixture that causes the mix to ignite at the wrong time (or wrong place).

Thinking about this when driving the car, I noticed that there was a break-over point with the throttle that changed as RPM increased. If I floored it from a stop, I'd get horrific knocking, but if I rolled on the throttle I could keep opening it up without causing any knock.

This makes me think that the root of the knocking is maybe a carb problem and that I could maybe address it with richening the mix. Of course, I'll have to research that one - the carb came with the motor and car (4bbl Autolite, I think).

And a quick BS-meter question. The car's been worked on by a mechanic who specializes in old Fords, and while he's done great work, he's said a couple of things that don't sound right. First, he said that the motor couldn't handle conversion from downdraft to PCV, although later relented and did the conversion (the car is mostly only driven on Sundays by a little old lady (my Mom) who has trouble breathing, and the fumes from the downdraft were overwhelming).

So for the "real or BS" question - he also told her that this motor couldn't handle modern 93 octane gas (apparently due to all the modern additives), but that strikes me as wrong since I'm guessing the additives are mostly the same across the octane spectrum, and the only difference is the relative willingness to combust. Anyone here care to corroborate or debunk this? I'm guessing that switching to "hi test" would also help the knocking.

Thanks,

JLW