Mustang Ii Vs. Newer Mustangs

Discussion in '1974 - 1978 Mustang II Talk & Tech' started by CobraIIboy, Aug 20, 2013.

  1. My only caveat before pulling the trigger on this plan is to ENSURE that you can source a decent set of headers for gt40 heads and a Mustang II. From what I understand, it's hard enough already to find headers for a regularly configured head.

    It's not to say that they don't exist. Just be sure before you run out and buy a wrecked Explorer.
  2. The GT40 heads are standard configuration 302 heads. Whatever fits the Mustang II, will bolt up to the GT40 heads. I believe Headman and Hooker both built headers for the Mustang II? Only the GT40P heads might present a problem because of spark plug location and guys are getting by that with different plug wires.
  3. Also, with ANY 1982+ 302/5.0 pushrod engine, you'll need to either order the Mustang II 50oz flexplate from Art Carr (if an automatic), or get your stock flywheel rebalanced to 50oz imbalance by a competent machine shop (if a manual) to run the stock bell/transmission.

    (Art Carr contact info here: )

    (The other option would be further modification to fit a different bellhousing, flywheel/flexplate, and clutch/torque converter for use with a different transmission.)
    #23 74stang2togo, Sep 17, 2013
    Last edited: Sep 18, 2013
  4. Ok, here's my 2 cents worth. I would try to get a hold of a HO 5.0 from an 87-92 Mustang/Mark VII. Reason being is that they have a better cam and forged pistons for upgrading in the future without getting a full on rebuild (assuming you wouldn't need one...). Then I'd hunt down the early GT40 heads from an Explorer (3 bar heads, not the 4 bar "P" heads) for use on the HO engine and install 1.7 rockers and upgraded valve springs. Personally, I'd stick with fuel injection. I would find a GT 40 style Explorer upper and lower, use a Mass Air harness with a good Mustang 5.0 computer. A9L sounds right, but might be wrong as I am thinking off the top of my head. I would then replace the injectors with second gen 19 pounders with the 3 hole nozzles for a little better atomization. Hopefully you could get one with the flexplate/flywheel that you want to use and install the tranny of your choice. It may or may not require a little massaging of the tunnel, but would be worth the extra effort under the car. If you go with the AOD auto, don't forget to check the first servo retainer c-clip. They have a tendency to expand under high rpms, letting the servo drum grind into the back of the pump in the transmission resulting in premature failure. Someone makes a spiral lock ring replacement to use in place of the c-clip. Disregard if you plan on running a T5.

    Sounds like a lot, and it may be a lot for you. I basically did this with our 84 convertible and it runs very well! I may have gotten lucky in my shopping adventures, but I got a hold of a 90 Lincoln Mark VII for $400. Set of heads were another $400, springs were about $200, gaskets around $90. I haven't gotten the rockers yet, but I am expecting another $200. Computer was around $75, harness was another $150 iirc. Mass air meter and adapter (our meter was from a Mark VIII or a Town Car iirc...) was something around $40, explorer upper and lower with a 65mm throttle body ran about $175. Injectors cost $80. So everything included would have run me around $1800. I suppose you can get the Explorer engine from a scrap yard for something like $600? You would have the intake and heads, but either hyper or cast pistons and the cam is made for low end grunt. Not a bad starting point depending on your intentions, but will also require performance upgrades for Mustang duty imo. So it basically boils down to what you want to do with it. Whichever path you go down, either choice would serve you well in the end.