These guys are local to me and who I bought my standalone harness from for my sand car. They are one of the top motorsports engine builder/parts supplier in the area. They do marine, street, and off-road engines. The guys at CBM know their stuff.
Yes, it is a harness only. The plug ends on the harness will be the same regardless of engine displacement. I was suggesting that harness could be used in conjunction with a used MEFI computer, which you would also need to source on the aftermarket. Finding that NLA NOS kit is certainly...
There are likely over a dozen ways to add IAT and 02 sensors to make the engine run in closed loop, but they are pretty much all going to involve a new ECM, Harness, and tuning. Holley has some self learning/tuning options that are probably in the $3k range, but when youre looking at that kind...
Also, i know there are at least two versions of the MEFI4, the 4a and 4b. One is preferred over the other, but i cannot recall the differences or why the preference.
I suspect this harness would work on the SBC even though it says its for a 502.
https://www.ebay.com/itm/165520581042?hash=item2689cba1b2:g:41gAAOSwaztinlc5
MEFI4 computers are commonly used in sand rails out west here due to their ability to survive the elements so well. You can buy a MEFI4 harness and a used computer, add in the necessary sensors that you are missing, and then have someone custom tune the computer for you. This could save you...