Strange timing problem Help!!!

[rrenie]

86 gt 225000 on stock 5.0
Had a lifter go bad totally collapsed rocker came loose replaced lifter
put it back together. Had marked distributor placement before tear down.
Ran ok but bad miss at higher rpms above 4000
did not check timing with light as I was in the middle of nowhere when this happened.
Now I find that I am 2 plug wires clockwise from number 1 for it to run.
Do you think the timing chain jumped? Why would it still start, run fine except for really bad mileage? 10 mpg or so.
So here I am treating the number 4 as number 1. It runs. How is it running. Should I tear it apart and check the chain?
Help please

[FM2NOTCH]

sounds like you need to reinstall the distributor, find tdc on the number one piston, set the timing pointer at the balancer on 10 btdc, install the distibutor with the rotor button pointing directly at the number one on the cap, the number one on the cap should be at the back of the cap and be pointing towards the intake, install the wires counter clockwise, HO firing order is 13726548, standing in front of the engine 1234 is on the passenger side, 5678 is on the driver side,fine tune the timing at 10-15 before tdc with the spout removed if it's still efi or the vacuum advance plugged if it has a carb, lock it down and reinstall the spout or vacuum advance line
for some reason efi engines require the distributor to be installed like described above, if it's carbed number one wire can start anywhere as long as the the number one wire is matched to the position of the rotor button