Summit Racing - SSBC front brake calipers, searched and verified by Summits website for the 78 K5 Blazer...

CPB-OE59CT
CPB-OE58...
https://www.summitracing.com/search/...alipers&page=1

THEY DONT FIT. The mounting bolt centers are 5-1/4 " , should be 7"
The pads are wrong also.

They came in nice boxes...

 

Are you sure you have the original axle? A lot can change over the course of 47-ish years. I seem to recall a change in the brake design somewhere around the 1979 time frame, but I could be wrong. It has been a number of years since I went down that rabbit hole when I was collecting the axles & axle parts for under my K5.

Also worth noting is that there may have been different brake packages which would fall into RPO codes on the SPI label inside the glovebox (assuming it is still there).

 

Yes, I know more about OUR VEHICLE than you do. I KNOW its all original

The TOPIC is not me, my vehicle, RPO codes etc..

The TOPIC is Summit said they fit, they dont.

Prehaps a reply on topic?

 

Thanks for the clarification. Hey, shame on me for trying to figure out what they might fit and pointing out how to get to the bottom of it. Yeah, totally off topic in every way imaginable.