I have always been a BIG fan of 67-72 Chevy trucks, and even bigger fan of 69-70 GMC's. With a new adition to the family, it was time to find a Suburban. It was getting harder to get the baby in and out of the back seat of a 2 door Yukon. I knew what I wanted and my wife really liked the idea. It had to be a GMC. I needed a 4x4 living in CO, and I would really like to find one in Copper. So, here is what I found.
Now to start the build... First was to get it to reliable daily driver status since my wife would probably be driving it more than me for the time being. I am not a fan of leaks, and decided this was the first problem I needed to address.
It originally had a 350, but had a 400 installed by the PO. I checked the casting #'s to see what I was dealing with. I got the block casting number by laying a piece of masking tape behind the head and rubbing it with a crayon.
And thats when I found my first concern. The head casting was 3998993 which only showed to be used on 307's and 350's! This cating also had either 1.72" or 1.94" intake valves! I needed to make sure the heads had the steam holes, and atleast 1.94" valves, so into the engine I went. I was very happy with the condition of the valve train, usually, I'd find more crud under the valve cover than this.
One thing that made me want to keep these heads is the shape of the intake ports. Most SBC heads have the extra material cast in the upper wall for the valve cover bolt that causes port match interference. These don't.
The temp dropped below 5deg, so to wrap it up for the day, I threw a temporary steering wheel on.
