ok 302 heads late vs early crap
my question on the 318 heads ties in with nm9's question
Did you port them as discussed in the sticky at the top of the page
evidently 318's can make a high velocity port head even DIY
I see useful for street, tow, most everything that is not going to be high rev
obviously they will not feed a 340 or 400+ at high revs but think of the great throttle response below 4000 and a terror stoplight to stoplight
If they just have the big valves put in plus a bowl blend- well run them till you can get some heads that better fit your new needs
one caveat I never try to make up with a cam low flowing heads- you loose your low end and the head limits the top end no matter what the cam
you can build a broad torque curve but it will fall off at the top end- best you can do
your 318s may flow better now than stock X's or J's and have more velocity
BTW I would not think it (the 509) would come in till a higher rev than that
so back to fuel, compression, how do you want to drive it