@ greg
If your '67 engine problem isnĀ“t finished:
All 66 and 67 Oldsmobile 425 V-8 can be identified by an engine unit number that stamped on a machined pad on the front of the RH cylinder head (behind the alternator). A Toronado engine should begin with a single letter prefix (ident the basic engine displacement), followed by unit number and a further letter (ident for a special high performance version)
Should be then:
1966 and 1967 -
N (unit number) TThe 425 block casting number is located at the front of the block, between the intake manifold and the timing chain cover.
1966 to 1967 -
389244Casting number of 1966 cylinder head is located just below the valve cover in the middle of the head on the exhaust outlet.
Should be 1966 -
389359 or 1967 -
394548From 1968 till 1976 the 455
Toronado engine unit numbers are stamped onto the oil fill tube (should not used for identification because it is easily switched!).
1968 - US or UT
1969 - US, UT, UV or UW
1970 - US, UT, UV or UW
The block casting number (much better for ident) is located at the front of the block, between the intake manifold and the timing chain cover.
1968 to 1976 -
396021Casting number of 1968 cylinder head is located just below the valve cover in the middle of the head on the exhaust outlet.
1968 to 1969 -
3945481970 -
403686 or (W30 only)
404438Hope it helps
Roland TOA#860