I've got an '84 Bronco w/ 302. What octane fuel should I be pumping through this thing? I think I hear some pre-detonation occuring, but I can't tell for sure because of my glass-packs.

Please advise.

 

Your's is carbed while mine is EFI (don't believe it makes any difference, though), but I run 89 through my '85. I could probably get away with 87. Your detonation could be from your initial timing being advanced too much. If it's to spec, you may also have internal carbon deposits causing the problem. I run a bottle of STP Gas Treatment through mine on every other tankful. This is supposed to keep internal deposits down, as well as keep water out of the fuel. At 145K miles, mine seems to be running great, with no pinging or detonation.

 

 

I can't imagine there being any carbon deposits in the engine since it only has about 2000 or so miles on it. The timing is set at 8 degrees BTDC, as specified on the little sticker under the hood. I put 93 in it on Friday, and it seems to be working fine. I'll try 89 next tank.