First neither one of those cars were mine,Somwhere there are some Pics of mine but I could never find them, Late in 61 Pontiac did offer a 421 SD with 306 heads(from the rare 373hp 3x2bbl) and it was rated at 373hp because of the small heads. When the 62 was introed it had the bigger heads(127s) and required a different intake 2x4s had 405hp, single 4b was the nascar motor rated at 380 with 11-1 comp because I also drove the car on the street I opted for the 11-1 engine. the car ran great but I had to retard the timing and clutch fans hadn't been invented yet so it ran pretty warm. OK the grey Ghost story. as you know Pontiac did make a all out drag car in 62 (aluminum bumpers fenders hood etc) in 63 Pontiac made a last ditch effort to stay with the stage 111 hemis with the aluminum package so they did everything the could to strip the weight off the 117wb Catalinas even aluminum and drilled out frames which would shave about 400lbs and bring them down to their advertised shipping weight of 3600lbs and painted them silver Metallic hence the name Grey Ghost, My friends Ghost fully stripped down to 3300b and running a 480 inch motor could turn 10.90s and pull the wheels a few feet of the ground
How did I get my Motor,,There was a guy who lived in Morrision IL named Arnie (the Farmer) Beswick who had plenty of them
The three years I ran my car all I ever had to do was freshen up the heads. change out the Mackeller#10 and fresh valve springs, My Trans would last maybe a half a season before going soft me. I suppose if I didn't drive the car on the street it would have lasted longer