[Redhook_98]

Will a set of Mac long-tubes hook up to a short BBK H-pipe w/ cats? I erroniously ordered a BBK H-pipe w/ cats to replace my off-road H-pipe, then found out the headers were Mac. Or do the headers and short pipe have to match (i.e. Mac and mac, or BBK and BBK??) Yep, still trying to figure out what this guy put into it.....
The BBK H-pipe will be here Wednesday and I am hoping it will fit....

Also, what is the correct amount of fuel pressure for a modified 5.0? What are the proper plugs to run with these mods? Gap? Where should timing be set?

GT-40 intake
B303 cam
1.7 Roller Rockers
73mm C&L MAF
70mm BBK TB
30lb injectors
Jacobs 5.0 GT ignition (still not working correctly)
BBK Cold Air intake
Edelbrock Performer Heads
Underdrive pulleys
Mac Long-tubes, off-road H-pipe and Flowmaster cat-back
4.10 gears
Tri-Ax shifter
Adjustable Quadrant
Centerforce Dual Friction clutch
NOS 150hp Power Shot
Sub-frame connectors
Koni Adjustables
Aeromotive Fuel Regulators (not yet installed)
BBK Fuel pump

......and bad brakes..... (not a good combination)


Once again, thanks for any input or suggestions you may all have... I am new to the Mustang crowd and still trying to figure these things out. I am a previous Pontiac guy before I saw the light...

[Vortex]

the brands dont have to match... bbk headers, mac h-pipe, flowmasters.. etc.
there is no correct amount of fuel pressure.. you have to find the right mixture.. buy or rent an air/fuel guage...
autolite platinums would work well in that setup.
factory gap or you could open them up just a hair.
did i get all the questions?
hope this helps...

Did you get the H pipe specifically for long tubes? Also, with fuel pressure, a good ball park figure to start with is 40 psi and adjust from there as needed. I like to adjust on the fly...ie., at the track, pull 2 lbs out until I slow down, then add 1 lb until I get back to my speed. You're looking for mph here, not ET.

[foxtrotter]

Take an Analog Volt Meter and place it somewhere you can view safely while driving. Run the positive lead from Volt Meter to the O2 Sensors signal to the processor/computer wire. Ground the negative wire to the chassis. Run the car at several different operating conditions, WOT, idle, under load in each gear and note meter readings, ie: 0.7V = lean, 0.0V=rich, it's been a while, but essentialy the O2 sensor heats up under lean conditions and creats a voltage that tells the computer to richen the mixture when it sees a voltage at the sensor. Vise versa for rich, no voltage. It's basicaly a toggle switch being swithced on and off. I actualy have a carbureted engine. My catalytic h-pipe has the O2 ports and I installed single lead O2 sensors into these ports and walla, instant rich/lean meter. This will also work with 3 lead O2 sensors, just learn which wires are what before going into this test blind.

[Redhook_98]

Well, consider this a lesson learned.... My BBK Long-Tube H-pipe arrived today and does not fit MAC Long-tube headers. The drivers side flange needs to come forward appx 3 inches to mate with the header and the passanger side is off at a slightly different angle. New MAC H-pipe w/cats now on order thru Proficient. Oh well, live and learn I guess.

[jjd975]

Redhook_98

Edelbrock heads require the Autolite 3926 spark splugs. Since you have a 150 shot get the 3923s and gap them to .040. Dont forget to use anti sieze on the plug threads.

Timing is different for all cars. Your aluminum heads will allow you to run more. I run 18* most of the time. I suggest to start at 13* and work your way up till you hear it ping then back it off a degree or two. Better gas will help.

Fuel pressure is kind of the same way. I would set it to about 40 like mentioned.

Whats up with your ignition? If it messed up I'm not to sure I would spray the car.

[jjd975]

Dont be surprised if most places dont stock the 3923 plugs. Napa usually has them.

[Redhook_98]

Thanks for the help with the plugs. I disconnected the NOS this afternoon and will be selling it vice using it. It was set up to race by the last guy who owned it, and I am putting it back on the street. I'll probably pull the 4.10's and stick in 3.73 or maybe lower as well.

I am still working on the ignition problem. I am replacing the O2 sensors, EGR/sensor and anything else that may be associated. Since my first posting, I have found where there had been a small engine fire in the rear of the compartment where the NOS solenoid actuator was located. No damage to the actuator, but there are some burnt up wires and vacuum tubing. Trying to replace all of this as well. The O2 sensor pigtails have been burnt pretty bad on the collectors of the long-tubes. Replacing them to.

Does anyone have a vacuum diagram for the EGR valve area, and a schematic for the hoses dealing with the emissions (i.e. air pump/exhaust tubing).

As for the Autolite 3926 plugs, without NOS, what should these be gapped at??

Turning into quite the project! Thanks all for the help!

[jjd975]

Gap them at .050. I would keep the 4.10s if the car is going to be N/A and see the strip. At least try them for a while before you pull them. I think you'll find them to your liking.

[foxtrotter]

I would never use antiseize with components that heat up. Always remove componenets when engine is at room temp.

[benitoonly]

As far as the O2 sensor pigtails go, with long tube headers, much more heat is created, so you need to get yourself some heat reflective tape(summitracing.com) and wrap it around your sensor wires to protect them.