ld340 intake...mechanical temp. gauge???

You can actually buy a spacer like that premade. It's not the prettiest solution since it's not a matching contour with the water neck, but I put one in and it's worked very well. Looks pretty much exactly like the pictures above. Summit sells them (look up water neck spacer I think). I got mine from Race Part Solutions. It lists as big block only on RPS, but it shows it fitting a small block on Summit's site and it works in my car fine so far. It comes with two ports though, so you may have to plug one. I put a temp switch in the other port for my electric fans.