(I like your first name mate. You must be a handsome bloke)
First of all, what do you want this combo to achieve – torque, fast ¼ mile times, or just a show-pony, or reliable daily driver, does it need to be economical, will it be running on gas, etc?
This is just my opinion, but I reckon you chose one of the worse sets of heads out there to start with. A good set of small port alloy CHI’s would deliver the goods and only end up costing just a little more then what you are going to have to do to the old iron 4V’s, (yes they are over 30 years old).
I’d recommend the following heads for a non-stroker . . . http://www.chiheads.com/3V_185CC.php
You WILL need to have a revvy motor to create any form of torque-producing port velocity with those 4V ports, ‘cos torque is going to be difficult to find, (though a 408 stroker will help a lot), but a 408 is not what I’d call a revvy motor either (due to it’s long stroke, etc), unless you chuck some $$$$ at it and buy top quality components. If I read between the lines your budget may not cover this degree of attention/insurance.
Sell the O/C 4V heads on EBay and get yourself a set of 3V 185’s.
You’ll have HEAPS of useful tyre-shredding torque without the expense and hassle associated with stroking.
Good luck buddy.
PS - if it was me, I'd use a strengthened C4 and hi-stall instead of a Toploader.