B series heads?
Did your 383 actually have pistons above the deck?...........
FWIW, I traded in my '66 Sport Fury (also a 383) for the '68 RR in '75. What I recall, when I pulled the heads and scraped the deck by hand out in Dad's driveway, I could hang up the scraper on piston tops and had to rotate the crank to clear them. I can't tell you actual dimensions. However, it's something you don't forget when it's your first time doing it.
I don't know if the engine had been modified prior to my ownership. I doubt it was.
BTW, I also recall that engine being painted orange, not turquoise. That in itself tends to raise the eyebrows.
One thing I've learned about Chrysler products over the years is to never say never.......
My '69 383 Barracuda S came with 9" drum brakes on the front.
I've been told the "all 440 '72 RRs were badged
GTX"... mine was not.
A lot of folks have never seen or even know a marine 440 six pack carb setup to exist.
And I can guarantee there is plenty more I don't know.
