I have an 86 Ford 302 engine that was in an F150 but has casting number for an 86 Thunderbird. I have tried two different Sealed Power and one Cloyes timing chains and have new cam and crank cogs. All three new chains have too much slack. I have a new wider chain (Melling) with the same number of links and it has very little slack. What might be the issue? Thanks, Bill
Has the engine block been remachined? Specifically, have the block main bearing saddles been line-honed or line bored? If it has, that puts the crank closer to the cam and will make the timing chain loose. Slightly shorter timing sets are made specifically for this purpose. Maybe that is the Melling chain.
Of course, it could be an illusion. The double row chain may just appear to have less slack because it is beefier.