1986 Chevy K10 - sucks for power :(

[Graystone]

Lol, mines red cause thats the 1st bottle of model paint i found.

Silver Sharpe works great too

 

[Boone83K10]

Backfire indicates carb improperly tuned or timing. You can shine the light down on it from bw the fan shroud and ac. Use whiteout or silver sharpie. Change air filter and fuel filter

 

[foamypirate]

Backfire indicates carb improperly tuned or timing. You can shine the light down on it from bw the fan shroud and ac. Use whiteout or silver sharpie. Change air filter and fuel filter

It could also be a flat cam lobe.

 

[farmerchris]

if you had to revved the motor to get through the sand the 45 minutes before the issues show up ,you might of over revved the motor creating valve problems of some sort,bent or warp valves.that would cause the popping sounds and backfire with the loss of power too.leakdown test and/or putting air through the sparkplug hole will indicate if any valve are leaking