I am I will do the right thing but the only thing I am confused about is the heads, is it posible to have bigger valves in my 340 heads I understand it will be costly but will it be worth it?
What do want in the end? What car is it going into, and how do you want to use it? What gas are you going to run? 1.88 intake valve can run very well, You can also step up to 1.92 +.100 with 8 mm stem, or the 1.94 in various stem diameters, as well as 2.02 intake valves. I would be opening up/smoothing the bowls even with the 1.88's Not really a big deal. Your 1973 heads are some of the good ones. I don't feel the need for aluminum heads, as a matter of fact, I'm redoing a set of virgin 2.02 J heads now for my 340 that were on the shelf, but I can do everything myself, except for milling them .020 and .019 on the intake side.