We are having difficulty installing 390 with Hooker super comps into 68 engine bay. A year or two ago, I saw an adapter plate designed to be welded into the shock tower, which would give more room to mount engine and to change the plugs. I believe it was made by Eaton, but I can not say for certain. I wou appreciate it if anyone could direct me to a source where i might obtain a set of these plates. Thank you.

 

http://www.rrs-online.com.au/shocktowerproducts.php

RRS make a kit but its designed to go with coil over front suspension.
You would have spring clearance issues with stock type springs

hope this helps