This is now a VERY OLD radio approx 1980-81 !!, unfortunately we have very little information on this set ( no service manuals ).
It would seem that the set uses a xtal mixer PLL, and to get the lower coverage of 430-440 Mhz, you will have to change the Crystals X3 and X4 in the PLL cct.
X3 (tx) was 35.74417 Mhz in the 45A, change to 34.912 Mhz (45E)
X4 (rx) was 33.9275 Mhz in the 45A, change to 33.095 Mhz (45E).
For the 1.6 Mhz repeater shift (if needed) remove diodes D13 and D14..(PLL pcb).
To get the display to show 430-440 (rather than 440-450) ADD diodes D15 and D16. (PLL pcb)
We CANNOT guarantee that these modifications will work sucessfully