We installed the head gasket...
We installed the head gasket making sure the end marked "front" faced forward, followed by the cylinder head. Make sure the dowels are in place and fully seated in the block before installing the heads.
Typically when power is increased, fuel consumption is increased. Since our LX had a stock fuel pump and fuel pressure regulator, we knew it was a good time to upgrade, especially since we didn't want to start running lean with a new set of cylinder heads. Lean conditions can cause a misfire or detonation, to name a few issues.
Since we have bigger plans for our coupe, we went with a 255-lph pump. It may be overkill for our current setup, but now we won't have to go back into the tank. The pump kit comes with everything needed and installs easily. Two things we suggest purchasing separately are the filler neck seal on the tank and a fuel filter. The filler neck seal is prone to leak, and it's always a good idea to replace your fuel filter when replacing the pump.
Along with our pump upgrade, we decided to go with an adjustable fuel-pressure regulator and gauge. Using our chassis dyno, we were able to adjust fuel pressure to achieve our target air/fuel ratio.
The head bolt bores are designed...
The head bolt bores are designed for 1/2-inch studs or bolts. When using stock or aftermarket 7/16-inch head bolts, head-bolt bushings (PN 9680) must be used.
We lubricated both sides of...
We lubricated both sides of the bushings and installed them into the cylinder head.
We used Edelbrock's head-bolt...
We used Edelbrock's head-bolt kit (PN 8552). It is very important to lubricate the threads and the underside of the bolt head to ensure proper torque when tightening.
We torqued the head bolts...
We torqued the head bolts following the torque specifications and sequence included with our gasket kit.
Then we carefully installed...
Then we carefully installed the lower intake and torqued the bolts to specification.
The BBK Performance 255-lph...
The BBK Performance 255-lph fuel pump comes complete with everything needed for the fuel-pump swap.
It's easiest to lower the...
It's easiest to lower the tank using a lift and a transmission jack, but it can be done on the ground with a floor jack. Still, you should always use two people to lower the tank. It's also much easier when the tank is nearly empty.
After removing the lock ring,...
After removing the lock ring, which is on the top of the tank, the fuel pump module must be carefully removed by twisting it a half turn and tilting it gently until you find the sweet spot.
The new pump mounts in the...
The new pump mounts in the exact spot as the old pump.
The fuel pressure gauge screws...
The fuel pressure gauge screws into the adjustable fuel-pressure regulator, and the regulator mounts on the fuel rail as the original one did. Be sure that your new O-rings seat properly as you tighten the new parts.
Before starting the engine,...
Before starting the engine, cycle the key to pressurize the fuel system and check for leaks. Then with the engine idling, check for leaks again, and set the fuel pressure using an open-end wrench and a hex key. Ultimately, we locked the pressure in at 38 psi, which produced the best power and a safe air/fuel ratio of 12.8:1 at WOT.
Because our new roller rockers...
Because our new roller rockers were taller than our originals, we scrounged up a pair of taller valve covers from our bone yard. Unfortunately, this interfered with our throttle linkage, so we called up Latemodel Restoration Supply for a 1/2-inch spacer kit (PN M9486A52).
After reassembly, we drained...
After reassembly, we drained the oil, along with any coolant that may have drained into the block during disassembly. We opted for Royal Purple 10W30 synthetic oil and an FRPP oil filter (PN CM-6731-FL1A).
On our Mustang dyno, the LX...
On our Mustang dyno, the LX made a best run of 273 rwhp (277 with the graph unsmoothed and ice on the intake) and 299 rwtq-a gain of 30-plus rwhp and 21 rwtq over our GT-40P heads.