If you have all the factory components, use them, they work well.
There are safeguards built in to prevent damage to internal components such as the reverse lock out. I have seen the result.
The relay used in cletis diagram is a good alternative if the factory components are not available.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine