Gas tank relocation in a 1969 C30

[kulyeh]

I realize that there is a billion gas relocation threads, however I can't seem to find anything with regards to doing the rear gas relation in anything other then a C10. From pictures of member installation, the C10 rear frame seems a lot different than my C30. The main issue I am coming up against is I don't seem to have a large enough flat area to really get good mounting of the tank. Anyone have some insight into this?

[kwmech]

Which wheel base is the truck? My 69 is 157'' and I went with a custom mid ship tank---47 gal (if my math is correct)

[kulyeh]

It started life as a step-side longhorn. However, it hasn't stayed that way, thus the reason I am wanting to relocate the gas tank to the rear, i.e. like the C10. The rear cross members are different though so looking for options (since I have already purchased a Boyd tank) of how to mount it.

[Richard2112]

I have a 69 C30 that I relocated the gas tank. It was a Blazer tank though and not a Boyds

[gmc684x4]

C30 Frame is shaped like k10 and k20 trucks i used suburbon crossmembers and the tank outvoff about a 77 suburbon in the past
Tank mounts between the frame rails like it was designed
You may need to remove stock crossmembers to allow tank to mount behind the rear diff

[DA71Grande]

Are there any difference in a c20 and c30 frame? I just put a Boyd’s in my c20?

[kulyeh]

Originally Posted by DA71Grande

Are there any difference in a c20 and c30 frame? I just put a Boyd’s in my c20?

My issue is that when I go to mount it I don't have enough flat area to properly hold the tank. The tank mounting flange extends into the curved part of the frame as it goes over the axle. I could gain some more room if I trim the bottom part of the rear cross member off, but I am not even sure if that would give me enough. Hard to see the front of your install as it relates to the frame, but it appears you had enough flat area on your frame to bolt it up.