I have been swamped with work and family and holidays and just not been around here much,, it's nice to know I'm missed (LoL)
I guess after reading this I'm still not clear what direction your jumping.
If you r convinced to go Vortec,, then only suggestion is buy a set of NEW GM / USA castings,, not any fleabay rebuilt import junk... but that's just my opinion. (just an add here, the aussie imports are a decent casting, the junk I mention is the SE asia imports)
World and Dart both have a iron head in the 170-180cc range that would probably fit here.
The world heads are a tad big, but put a decent set of gears to match tire and equate to about a 3.73 effective gear and I wouldn't sweat the 200cc. The port velocity is fairly good on those heads so low speed throttle response isn't horrible.
They arent a set of $1500 AFR street eliminators, but for around $800 you get what you pay for,, and all of your existing stuff (head bolts, rocker arms ,rocker covers, intake, carb, pushrods,, bla bla bla) ALL work. That is a BIG plus over the vortec craze that IMO is surely NOT the end all of performance the internet has racked them up to be. . (I have 2 Vortec motors right now so I don't say that without Apples and Apples comparison to back it up)
http://www.jegs.com/p/World-Products...46700/10002/-1
It's pretty easy to spend someone elses $$$ but If it were 'me' I'd be exactly where C.L. is with the Brodie 180s, or AFR 180 eliminator,,, BUT aluminum heads brings the need for head bolt set with washers ($110) and undoubetedly shiney new roller rockers ($375) and shiney new cast / fabricated aluminum rocker covers ($125 - 400), and. and. and .. and this slippery slope kicks the budget out the window in a big@$$ hurry.
The ONE thing to keep in mind with this is,, SBC parts are not getting any cheaper. If you buy the boy something he can GROW IN TO, as the need for faster faster faster demands,, your giving the gift that keeps on giving. When 370-425 isn't enough to satisfy his addiction,,, bump compresson and step into a roller cam and hes kocking on 500+HP without having to buy new heads.
One thing to maybe check in to... My machine shop is buying bare castings from AFR / Brodix/ Promax etc and filling them with decent 'street grade' valves, springs, retainers and such. They can beat the online $1500 price of the AFR street / comp heads by a fair amount. You might check with local speed shops and see "what's up" in your neighborhood.
OK,, back to work. just my 2¢ nd hope it helps some