Service manual

5
Chart 2
CAUTION - Improper oil pump installation due to
incorrect identification of crankcase year group may
result in engine damage.
2. Crankcase Modification - 1970-1972 Only - Plug
3
⁄16"
Oil Overflow Hole.
A. If engine has been removed from chassis,
CAREFULLY enlarge hole in Picture 7 with .203"
(
13
⁄64") drill. If engine has not been disassembled apply
grease to bit and both ends of hole to catch chips
Wrap masking tape around drill .225" from drill point
to use as depth guide. If engine is in chassis,
enlarging hole may be difficult. In this case hole may
be tapped without enlarging, but extreme caution is
required to avoid breaking tap off in hole.
NOTE - Drill bit o.d. is very close to hole size and may tend to
distort hole if drill is not steadied.
CAUTION - Distorting hole may cause poor thread fit after
hole is tapped.
B. Using
1
⁄4-20 tap, carefully tap hole deep enough for
1
⁄4-20 set screw provided with kit to rest flush with or
slightly below gasket surface. Use straight edge to
confirm set screw does not protrude above gasket
surface. See Pictures 8 and 9. If necessary, reapply
grease to both sides of hole before inserting
1
⁄4-20 tap.
NOTE - Do not tap hole so deep that screw can be threaded
completely through hole. Objective is to have screw tighten in
Kit Part No. Year Group Required Steps Optional Steps
31-6250 Fits 1936 to 1972 1,2,3,7,8,9,10 4 (1948 to 1969 only) §
31-6251 Fits 1936 to 1972 1, 2, 3, 7, 8, 9, 10 4 (1948 to 1969 only) §
31-6252 Fits 1973 to 1991 1, 3, 7, 8, 9, 10
31-6253 Fits 1992 and Later ‡ 1, 7, 8, 9, 10
31-6254 Fits 1948-1953 1, 7, 8, 9, 10 4 §
31-6255 Fits 1954 to 1969 1, 7, 8, 9, 10 4 §
31-6256 Fits 1970-1977 1, 2, 3, 7, 8, 9, 10 5
31-6257 Fits 1978 to 1991 1, 3, 7, 8, 9, 10
31-6258 Fits 1992 & Later (Pre '89 shaft) 1, 7, 8, 9, 10
31-6259 Fits 1970-1972 1, 2, 3, 6, 7, 8, 9, 10 5 §
31-6260 Fits 1970 to 1991 1, 2, 3, 6, 7, 8, 9, 10 5 ( 1970 to 1972 only) §
31-6261 Fits 1992 and Later 1, 7, 8, 9, 10
31-6262 Fits 1970 to 1972 1, 2, 3, 6, 7, 8, 9, 10 5 §
31-6263 Fits 1948 to 1953 1, 7, 8, 9, 10 4 §
31-6264 Fits 1954 to 1964 1, 7, 8, 9, 10 4 §
31-6265 Fits 1965 to 1969 1, 6, 7, 8, 9, 10 4 §
31-6266 Fits 1970 to 1977 1, 2, 3, 6, 7, 8, 9, 10 5 (1970 to 1972 only) §
31-6267 Fits 1977 to 1991 1, 3, 7, 8, 9, 10
31-6269 Fits 1992 and Later‡ 1, 7, 8, 9, 10
31-6270 Fits 1965 to 1969 † 1, 6, 7, 8, 9, 10 4 §
31-6272 Fits 1965 to 1969 1, 6, 7, 8, 9, 10 4 §
Picture 7 Picture 9Picture 8