I believe a "Jasper" 383 is a low dollar engine rebuilder. Most likely a bored 383 with maybe a RV cam. I used to sell "Jasper" engines when in the parts business.
You might read thru here and do more searches over at BBD.com.
http://www.bigblockdart.com/techpages/linkage.shtml
Plus, is it your drag link or sway bar hitting as you mentioned both in this thread.
Well, look forward to updates when you do free up some time to get back working on it! Quite the work in progress and it should fry the tires off it when done.
Thanks for posting!
Kim
Heck, my .02 would be if your spending the monies to buy H-beam rods and an aftermarket steel crank, why not just get a stroker kit!
However the 10.5 compression would wake the 400 up with the right other components.