Does anyone know what heads were used fo a 08/92 build date 7.4 carb, 300 hp. PITA to pull the cover. Peanut ports or Oval or Rect. Called Mercruiser all they could say was "Oval" port. Also, Thunderbolt IV ign. HEI or not. Time to get cap, rotor and plug wires. Thinking of changing the coil to a MSD Blaster 2.
Thanks for any help.

10114182...454.......91-up...4-bolt, Gen.V - That's your numbers I think.

Big combustion chamber, low comp, should be lge oval port heads.

Good coil choice. Get the MSD 8.5mm leads too.

That probaby has peanut (small) port heads, the only way to know for sure is to get the casting number under the valve covers.