Yes I never noticed that. Slim is the one /round carb flanges the GMC? My head does not have the letters on the port runners but I think it was camnoflauged to run circle track stock classes. It had some dull green paint on it when I got it. I was told the man I got it from found it in a barn while in oklahoma looking at old syock cars. I've had it since 93-94?? Need a powerglide valves to assemble it I guess. It appears to have beem milled quite a bit. 1 OL REDNECK
