[Herald1360]

Ahh...., disconnect the AM IF secondary from the grid of the IF valve too and wire the VHF IFT working coil in series with the AM IFT primary (if it's the original VHF primary, it'll be connected that way to start with). Neither AM nor FM will be as selective as intended, but with a bit of luck there shouldn't be much difference otherwise.

Another thought.... if the AGC line feeds the IF grid via the IFT secondaries, you'll need to take the grid leak to the AGC line, rather than ground.