Join Date: Sep 2005
Location: Geismar, LA, USA
Re: Covert 91 Vic into HO
Use the Mustang upper intake plenum (you can rotate it 180* to fit right). The CV plenum is simply not going to flow enough. For the vacuum hoses on the plenum, hook the large hoses to the large ports and small hoses to the small ports. For some things, you may need to run longer hose to match things up to the ports properly. Here are the things to make sure are getting vacuum:
Vacuum tree on firewall (big port)
MAP sensor (big port-- bolted through windshield wiper valley, near heater hoses on firewall)
Fuel pressure regulator (small port)
The little solenoid that comes off the T from your cruise control servo (should run up the passenger side and have a medium-size vacuum line attached to it)
Smog pump (this may actually run off one of the vacuum lines on the passenger fender well)
EGR solenoid (small port)
You'll need the Mustang throttlebody- it's a 60mm, while the CV is 50mm. You need to swap the throttle lever from the CV throttle body to the Mustang throttlebody. There are small spots on the bottom of the levers that look like welds. Grind them off and you can pry the lever off the shaft (be careful not to mangle it). Swap it to the Mustang TB and have someone put a quick spot weld on it. You need to take your stock EGR spacer and have it bored out to 60mm at a machine shop (the max is 63mm) to match the throttlebody opening.
You can use the CV wiring- it's fine, the injector firing order is in the computer itself. Make sure you do the plug wires in HO firing order, though (1-3-7-2-6-5-4-8) or it won't work. Your distributor is fine, too.
You'll need an ECM from a Lincoln Mark VII (they were built from 1987 until 1992) if you have cruise control. If you use a Mustang computer, you'll lose the cruise because the Mustangs had a different computer to control it. If you don't have cruise, a Mustang (1986-1988) computer will work (if you need a temporary fix until you find the Mark computer or if you don't care for cruise), but you can't use 1989 or newer because they were MAF. You can upgrade to that later, when you get a better feel for things.
The reason it's running extremely rich is because you're not getting enough air through your 50mm throttlebody and your stock CV upper intake plenum (and you're not running on all cylinders, so you're dumping fuel). You need to use the Mustang injectors, too- they're larger.
That's a lot to take in, but you've made a HUGE step by getting the engine in and ready to roll. Now, it's just a matter of making a few minor modifications to get it all finalized.
Good luck and if you need help with anything else, be sure to post up!