Thank you for all of the responses . The winner for me after much research is a 383 with a 450 stroker kit and 150 shot of NOS .
The" easy" to find 360 LA blocks are not so easy to find and builder 5.9 Magnums are indeed every where but not cheap. $750 to $1000 for a builder in Chicago land. Been looking for 4 weeks . Put the $$$ towards the 383 . I have 2 69 383 blocks , I have read that compared to a 5.9 magnum the casting is much thicker in critical area,s .
Plus 440 Source Heads at $1100, vs Good aftermarket 5.9 heads, cool factor, forget about it . thumbs up 383