they are either on the head(s) or on the intake manifold,i got a 79 gmc sierra classic that has the original motor and the numbers are hidden under 33 years of grease and grime there, so get a wire brush, wd-40 and some rags and see if you can find em, that should give you a place to start. let me know how it goes.
1949 Dodge Coronet 1955 2nd Chevy 4400 1.5 ton 1955 2nd Chevy 3100 1/2 ton 1955 2nd Chevy 3100 1/2 ton 1957 Chevy 5400 LCF 2 ton 1966 Dodge D100 Sweptline 1968 Chevy P20 stepvan 1969 GMC LWB pickup 1972 GMC Sprint 1974 CP30 shorty bus There are three things that I've learned never discuss with people: religion, politics, and the Great Pumpkin.----Linus Van Pelt Trying to understand the behavior of some people is like trying to smell the color 9  | 
