flywheels on 4.0's

I Swapped my Renix 4.0 for a HO 4.0. Are the tone rings on the flywheels the same for both engines or are they different? I put the Renix on there and its in, it ran for a minute or so, then i shut it off. i can't seem to get it to start again though. I have spark, i'm not sure if its intermitent or not though. I have Fuel pressure on the rail, maybe a little too much. i can hear the injectors firinging and the plugs get fouled pretty quick. if i crank it for a bit it seems to kick on one cylinder every 5 seconds or so. Any sugestions welcome.

thanks,
Donovan

Different -- I think