More details from Fran and Gord,

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I have:

Basic Carburetion and Fuel Systems No 5. ISBN 0-8227-0101-0. Published 1975.

Basic Ignition and Electrical Systems No 4.ISBN 0-8227-0104-9. Published 1975.

#3 was 1971. #6 was 1977. I suppose you are correct - the numbers refer to the revision. My book has 192 pages just like book #3. Maybe book #3 would be better for the stovebolters...
Looks like you can get a copy for less than $2.

---- Gord message ends here ----

Woot.

-W