• Hello there guest and Welcome to Fox Body Mustangs forum, This forum is intended to be used by enthusiasts of the Fox body Ford Mustangs (1979-1993)!
    To gain full access you must Register. Registration is free and it takes only a few moments to complete.
    Already a member? Login here then!

89 notchback project


New Member
Hi I’m currently building my foxbody and I’m running a 331 stroker with AFR heads and full maximum Motorsports suspension including with a 03 IRS...I’m new about building cars but I’m very interested to learn. What are other good parts for a 331 block ? What type of intake can I use? Or springs and rockers can I use? What do I have to do to make high numbers ?


Active Member
Welcome to the forum!

I take it you're currently putting this engine together? If so, I'm curious if you've chosen a cam already. Your valve springs will be decided by the lift of your cam. That is, the springs will need to be rated to handle the amount of lift.

As for rockers, you'll want a good quality roller rocker. There's a few specifics though. There are pedestal style and stud style heads. You're afr's are probably stud. If stud, you need to know if they're 3/8" studs or 7/16". Next, you'll need to decide on 1.6 or 1.7 ratio. Standard rocker arm ratio is 1.6. The 1.7 ratio is available basically for folks that want a little more performance out of a stock or mild aftermarket cam. If you're still shopping for a cam, get your lift through an aggressive cam lobe...not 1.7 rocker arms. There's a little less stress on valvetrain that way.

On the subject of cam specs, you should match your intake and rear end gear ratios accordingly. The heads come into play here, as well. The goal is to find/create a combo that keeps you in the ideal power band for your driving conditions. Your cam specs should list the power band. For instance, 2000-5500 rpm. If you're planning to build a street car, you may want a cam that starts making power closer to 1500. You'll spend more time in the lower rpm range. Heads (listed by intake runner size) should be in the 165-185 cc range. Anything bigger and you'll have to spin to higher rpm to start making power. Your intake choice should match accordingly. Lower rpm range for street, higher range for a track car. Your rear end gear choice will help put you in the rpm range your aiming for.

There are always exceptions and we really need to know what you plan to do with the car. But the above info should at least point you in the right direction.