tires/tubes for my '66

Howdy folks, need some advice in regard to tire sizing on the 'ol 66. The tires on it are total shot (cracked & hard) and to drain 6 yrs of rain water out of them, I had to drill holes in each one through the tread.

the rears are marked 7.50-12 2 ply and the fronts are marked 4.80-4.00-8.

Everything I see is has a number ahead of the 7.50 (ex. 27-7.50-12)

suggestions as to what I should look for?

Thanks

HI I AM ASSUMING YOU HAVE A 1966 SEARS SUBURBAN, YOU MAY USE ANY TIRE SIZE OF YOUR CHOICE IF YOU HAVE RIMS WITH THE PROPER WIDTH, YOURS IS PROBABLY 22" TALL ON ABOUT 5"TO 6" WIDE RIMS, IF THE RIMS ARE NOT RUSTED AWAY AND YOU WANT TO REUSE THEM GET SOMETHING LIKE 23X8X12, IF YOU WANT A BIT LARGER AND WIDER REAR TIRE LOOK AROUND FOR A PAIR OF USED 5 LUG WHEELS, MOST ALL LAWN MOWERS WITH 5 LUG REAR ARE ALL THE SAME BOLT PATTERN, BEST TO FIND A PAIR OF 7" WIDE WHEELS AND ORDER 23X10.5X12, IF YOU COULD LOCATE A PAIR OF 8" WIDE REARS THEY WOULD PUT MORE RUBBER ON THE GROUND, (MAKE TIRES SPREAD OUT WIDER), YOU CAN'T PUT WIDER TIRES ON YOUR NARROW WHEELS, IF NOTHING HAS BEEN CHANGED ABOUT THE REAR HUBS YOU HAVE ONLY 3 LUG BOLTS TO MOUNT A 5 HOLE WHEEL, YOUR FRONT WHEELS ARE ALSO NARROW BY TODAYS THINKING, COULD CHANGE THOSE OUT ALSO, PROBABLY A CLOSE REPLACEMENT WILL BE 13X7X8, THE FRONT WHEELS ALSO FIT SEVERAL BRANDS OF TRACTORS, SO WIDER WON'T BE TOO HARD TO FIND, THE LARGER FT. SIZE COULD BE 15X8.5X8.
GOOD LUCK
JIMMY

Thanks Jimmy --- good to know --- all info is good info