I've heard that the heads from a 350 will fit a 305 and give you more power. How true is this? I have a carbed 305 in mine and would like to get some heads from Summit to put on. Would everything hook up or would I need special parts? And wait for it..... anyone know roughly how much more power this would add? lol
They will bolt up but be cautious of losing too much compression. Another thing to remember is valve size. For a 3.766 bore, using the 52% intake valve rule on a race engine, the intake valve should be no bigger than 1.96 and I am assuming this is not going to be a maximum effort engine so you really need to watch putting too large of a valve in that bore. Also, the small bore will shroud a big valve and hurt the airflow. If you are trying to make this a fairly hot engine, stay with a 1.94 / 1.50 valve combination. The right cam and intake will really make it come alive. We have some cast iron heads we use in this application and they work quite well.
A side note, the 383 crank in this (with the matching pistons of course) makes 334 inches and it is a real shocker to most people. I have built a lot of them for trucks and street rod guys. The small bore is a little friendlier to pump gas too.