I’d hold onto those X heads as well... They seem to be more rare than a 340 itself. I’ve seen really awesome builds with 360’s. Here’s a question. I currently have a performer 318/360 and Carter 625 carb. If I changed those out to a Performer RPM intake and a bigger flowing carb, will I need to modify anything else, such as degreeing the cam? Or will they be ok to just bolt on? These are two components I plan on using for the future build and an upgrade in my opinion to what I currently have. Also, mechanical vs electric choke carbs... What do you prefer and why?
What changed in ‘72 besides the heads? I know compression dropped considerably to 8:5-1 from the 10.3-1 in ‘71 and was only rated to 240 net HP. I’m guessing emission controls.
yes the smaller intake valve-1.88 inch. the Low compression "flat top" pistons.- The earlier pistons, at TDC were.018inch above the deck. The crank went from forged to cast with external balance. That, and different intake carb air cleaner for that early 70s emission attempt.
P.S. X heads on a 360- double check if the larger valve will scrape the cylinder wall. there was something about that, i am not sure if it was 360 or 318. 318 definitely would be a concern as the bore is smaller than 4 inches.
Awesome! This is another area that I need to research a lot more... External VS Internal balancing.