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The bone stock '88 5.0 (mass air) has 130K miles, and has run a best of [email protected] mph. The head and intake upgrade should land us in the mid-13's, on radials. Late model cars have alot of electrical and vacuum connections, which can make the job intimidating. We recommend taking some pictures before disassembly, so you know where to put everything back. Removing the heads requires draining the coolant and oil, and depressurizing the fuel lines using the schrader valve located on the fuel rail. We also disconnected the h-pipe from the headers. The EGR coolant lines,throttle cable bracket, and a few vacuum lines need to disconnected before the upper intake can be lifted off.
With the upper off, we've got access to the fuel rails and lower intake. Remove the distributor before attempting to remove the lower. We didn't have the proper fuel line disconnect tools, so we simply swung the fuel rail and injectors over to the side. We also removed the AC compressor from its bracket and set it aside, without disconnecting any of its hoses. With the lower intake off, the heads can be unbolted and lifted off. The sludge and crud buildup is typical for a high-mileage motor that has never been apart. This is good opportunity to clean it all out. We even found remnants of a bee in one intake port!
The most critical part of the whole process is cleaning the head surface and intake valley. We used a shop vac to vacuum up the coolant in the bores. Then using gasket remover and carb cleaner, we methodically cleaned everything. About two hours later, we've got a block surface so clean you could eat off it. But then you'd have to clean it again...so don't!
As a final prep of the surface, wipe off any grease with paint thinner or similar degreaser.
With the locating dowels in place, the new head gaskets (Fel Pro 8548-PT2) are laid down, taking care that they are oriented properly. Remember, small block Fords only have coolant passing through the gasket at the rear of the block. Most gaskets have "FRONT" stamped in them to remind you. With the gaskets down, the Holley heads are set in place.
It's a good idea to use new ARP head bolts whenever replacing heads. Use RTV sealer on the lower bolts since they pass through water jackets. Always torque head bolts in sequence, beginning with the center head bolts and alternating to the outer bolts. Torque in steps (i.e. 30 lb.ft, 60 lb.ft, and 80 lb.ft.) Due to the raised exhaust ports, the AIR holes in Holley head are also .400" higher. Since this would cause a problem with the accessory brackets, the systemax heads come with another threaded hole in the stock location. To block the AIR holes in the front of the heads you'll need a 5/8" pipe thread plug, available at most hardware stores. The Ford threaded bushings using in the stock heads will not work (shown upper right.) The raised AIR holes requires that the AIR tube be lengthened about 1". Holley instructs you to use a hacksaw to cut the tube.
Then use the included compression fittings to rejoin the two tubes. The AIR tube is now the correct length and can be bolted to the back of the heads. Holley however neglects to mention the stock bolts to hold the tube to the heads will not work, as they are too long. You'll need to go to the hardware store with the bolt in hand and find one about 1/2" shorter in the correct thread size. The headers get bolted in place next. It's always a good idea to use antiseize or Teflon tape whenever threading steel fasteners into aluminum. We had replaced the stock restrictive headers with Dynomax shorties a while back. The 1 5/8" equal-length primaries will be a perfect match for the well flowing Systemax exhaust ports. Rather than use the stock pedestal mount rocker arms, we opted to convert to the more reliable stud-mount rocker arms. To do this we used Crane's pedestal to stud conversion kit (part no. 26655-16). The kit simply bolts to the pedestal mounts without requiring any machine work, and enables the use of a standard 3/8" stud mount roller rockers.

Holley recommends the Champion plug on the right. Unfortunately the large 13/16" socket size on this plug interferes with our header flanges. We opted to use the Autolite 5184 plug on the left, which has the same gasket seat, reach, and heat range.
Installation of the Crane conversion kit is very simple. Rather than a conventional hardened steel guideplate, the kit uses a plastic insert to guide the pushrod. This allows the use of the stock, non-hardened pushrod. The Holley heads require a slightly shorter pushrod than stock. Holley recommends a 6.400" pushrod, however we measured and deemed a 6.375" to be a perfect fit, and also a more common size. We picked up Crane's 36623-16 for about $80. The 1.6:1 roller tip rockers go on next. Setting lifter preload with stud mount rockers is easier than than fussing with the shims and torque settings for pedestal mount rockers. Simply turn the hex nut until there is no play in the pushrod, then give it another half-turn and snug down the allen lock. You still need to make all preload adjustments with the lifter on the base circle of the cam.
Shown here is the AC / PS bracket mounted on the stock head. For whatever reason the bracket would not bolt up straight to the Systemax head. We had to open up the holes to the next drill size in order to solve the problem. Another headache with the Holley heads is the fact the stock '88-'92 valve covers do not fit. The reinforcement ribs along the inside of the cover interferes with the valve springs. We had to grind all these flat to get the covers to work. Aftermarket valve covers will work, but require a spacer between the lower an upper intake in order to clear the throttle linkage.    
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