Cars with vacuum wipers had a dual diaphram fuel pump. The second diaphram was a vacuum pump. Dual diaphram pumps were hideously expensive. The wiper vacuum line was re-connected to the intake manifold by "thrift-minded" car owners. My great uncle had a model -T. At age 15 I learned a great lesson right off the bat. The spark retarder was on the left side of the steering column. I used to arc the crank handle enough to stand on it then jump. One day we hopped in to go down to the flats and check windrows to see if they were dry enough to bale. I got to yakking and forgot to set the spark retard. Everything seemed to go well until the engine bucked and tossed me six feet onto the hood
I thought Chick was going to die choking with laughter. I must have limped for a week.