Those heads are pretty much "unobtanium," been discontinued for awhile. Depending on what you want to do, a good shop could do a mild port and polish and top valve job on your stock heads. Then you could select an appropriate cam profile, and have someone like Competition Cams make you a nice match.
You are somewhat limited by the 3 valve head, and unless you are supercharging, a "Coyote" swap would be the way to get big power. Good luck.
You are in California, if those heads are anywhere it would be out your way.
yes they discontinue things, but keep in mind ford hasn't put 3V motors in mustangs for a while. maybe 10 years?
if you are looking for the heads my suggestion is join as many forums as possible and post wanted ads for them. then check up on them daily. also join and visit as many 3V and mustang sites that have 3V motors.for sale, also check those daily even multiple times daily.
they do pop up from time to time for sale. the key to buying is have cash on hand and be the first in line to buy them.
i have stage 1 heads on my bullitt. they were installed on it when i bought the car. i have stage 3 heads on the shelf with bigger valves waiting for my next motor build.
if you are looking for a bit more power in a 3V non boosted motor my suggestion is don't waste your $$$ unless you are limited by racing rules on what you can build. either add nitrous, upgrade to a coyote motor or go like i did and buy a Department Of Boost intake and supercharge your motor.
going non boosted it will cost you several thousand $$$ for maybe 50-75 hp and the 3V motor won't daily drive able friendly.
now spend a couple of thousand for a DOB intake will give you several hundred HP, 450 pump gas rwhp. at the bottom of the build chart. forge your motor add a TVS supercharger and the sky's the limit. i am currently at 650 rwhp on pump 93 octane gas and over 800 on 110 octane no lead race gas. i have connections and can build my own motor so it cost me less than $4K to build my motor. my next motor will be over 1000 rwhp on pump gas if DOB ever makes the intake he was hoping to build.
DOB has a website for more really good info on the products he sells. he also has a open facebook page where you can ask questions.
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