360 w/J heads-need help deciding

Don't mean to sound nit-picky, but there is no such thing as a "'69 J-head"! 1969 had 2931894 X-heads. J-heads came out in 1970 - 3418915. Done right, there is nothing wrong with either one as they have similar ports, but I'd check the actual casting number.

Too much porting may hurt if not done right.

Check which Milodon pan it has. The sump on their 8 quart pans will interfere with many headers. TTI's do fit. Not sure about their 7 quart.

I'd be more comfortable with less than +.060" overbore.

Don't forget you'll need a 360 LA B&M flexplate if it's not internally balanced and you use the 318 or other neutral balanced converter.