Retarding the timing might help. I'd try running a can of Seafoam through the fuel tank and another through the vacuum booster line to help remove some of the carbon build-up in the cylinders/intake system. Most pre-ignition in older vehicles is due to residual heat in carbon deposits in the combustion chamber. At about $5.00 a can, it's well worth a try before going with the timing adjustment.
I have 1986 f250 with 460,the last yr for carbs. they came with 2 air pumps n air injected in the exhaust,ran like ****,high idle n no power,had all kinds of vacumn leaks.In-laws bought it new.removed vacumn pumps2 n replaced exhaust with earlier manifolds.Replaced the timing chain with 1970 chain,they are not retarded 6degrees from the factory.replaced intake with one without ERR plate. I run 10degree timing n 87 octane.also the dist.has way to much vacumn,thats why she rattles under load. dont know about F.I. models
Disconnect the spout, check the initial timing with a light, should be 8* BTDC stock, if you're good there then suspect other problems. If it is advanced more than 8* someone may have messed with it before, these engines like 12* BTDC so I would think another problem is causing your preignition. Good luck!
1987 was the last year for Carb's.
There is no spout with a carb and DSII system.
10 degrees is stock, I'm at 12 with no problems.
If you have an issue with knock, point the finger at yourself for removing the EGR spacer.
As for advance, just get yourself a Crane Cams adjustable advance unit and follow the instructions.