Maybe 7 or 8 years ago a late friend (electrical engineer/designer) gave me data on ignition switches from the 1950s, the 1960s and 1970s. What I learned was that some were only rated for a max of 10 or 15 amps. Some others later were rated for a max of 20 amps but none were ever made to handle more than that except for a few special purpose switches for industrial/wrecker/heavy equipment use and those as I recall were rated for up to 30 amps. The other thing I learned from a gentleman who ran one of the NAPA stores here was that almost none of the switches they handled were marked for amperage ratings and you had to either get those ratings from the box or the data accompanying the switch or the company's data. He told me 30 amp was the highest rated three position keyed switch he could source.
This question came up when after converting to HEI and installing an electric puller fan my ignition switch failed. The HEI on start-up required around 28 amps and the puller fan needs around 25 amps. Essentially after just short use the contacts fused together and would not release. I ended up using a 30 amp rated switch made in Taiwan by a company named URIAH and a couple of 60 amp Bosch style relays to reduce greatly the amp needs of the switch. I did in a box in my attic find a switch made in the USA and sold by Standard Products. I had bought it around 1978 however I have no idea what the amperage rating is and there is no product number on the switch so I decided it wasn't worth the gamble. This same switch was made originally by AC Delco and copied by Standard and later by other manufacturers all over the world. The URIAH switch is an exact copy of that switch but rated at an honest 30 amps.
Hope this is helpful.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
