I’m going to install a 12SI alternator , 94 Amps, in my 1969 Skylark. I looked at Todd’s wiring harness and would like to get it however, I’ve come across more information which says I may need more than that. I have an HEI distributor which I’ve read that I would need a diode, also do I need to upgrade the battery wire to a larger size? Any information would be greatly appreciated. Thanks Jaye
The HEI has nothing to do with the conversion. No diode needed unless you are using an MSD box, but if you were, the same issue exists with the stock alternator. Technically, all you need is the plug for the SI alternator, https://www.amazon.com/Alternator-Harness-Connector-Chevrolet-Corvette/dp/B07DKRRVSV The rest is just wiring, http://www.buickperformanceclub.com/alternat.htm Todd's kit makes it easier, https://www.stage1restoration.com/product/alternator-conversion-wire/ You do not need to upgrade the stock battery wire.
Only thing different about the 10-12SI Alternator ( no external voltage reg) and the Old school (External reg).. Is you may have to bring the the rpms up for a moment to kick in the builtin VR... Other than that just buy Todds kit.... I kinda like that kit..... If not your good at soldering thats the way to go....
I appreciate the insights, I also like Todd’s kit. I’ll order it on Monday , hopefully everything can be completed in about two weeks from now. Thanks again Jaye
IF you use a relay to power the HEI you may need the diode: https://www.wranglerforum.com/threads/hei-questions.2386617/. Depends on where you get power to switch on the relay.
My engine harness is from Lectric with HEI wire installed so no relay, from what I’ve read I should be ok. Thanks, that was also interesting information you linked
I just thought of something, I may have to dig more into what I have. I have a relay on my fuel pump which only powers the fuel pump 3 seconds unless it receives a signal from the distributor wire.
