I know MSD 6a and Jacobs off-road boxs have been covered a lot. I am curious about the other kits that are out there like the jacobs miliage master, the msd5a, crane fireball. Has anyone used them. I am particularly looking at the miliage master box. Is that any good, does it plug right in? thanks guys

 

I installed the Jacobs Pro-Street Kit in the 1979 Bronco / 351, about 4 years ago. Jacobs provided mounting hardware, connectors, and guaranteed for life spark plug wires, total cost set me back - but I was desperate to put some high voltage spark into the old beast. Here are my experiences;

The connectors provided in the kit - don't waste your time with those - use your own butt-splice electrical 'crimp' connectors to make sure that the electrical connections are good. You want reliability - not installation convenience here.

Take extra time routing the wires through the engine compartment and protect the wire runs with those 'spiral plastic' wire covers from the auto store.

I mounted the Jacobs electronic brains (JEB) in the engine compartment on the driver side wheel-well area (where the factory tire-jack was located).

To deliver maximum spark, I wanted to keep the hot-wire from the Ultra-Coil to the distributor very short, so I mounted the Ultra-coil very close to the distributor cap on a modified air-conditioner compressor bracket. (I had the local machine shop modify the bracket to give me better access to the water pump, distributor, etc..) The bracket attaches nicely to the passenger side head & uses 2 or 3 water pump bolts.

The spark plug wires provided in the kit were cut to appropriate length and fit o.k. - but I was not real happy with using the 'old' stand-offs nor the separators provided in the kit.

They recommend using a brass-contact distributor cap & rotor (1979 was a good year) and these cost alot more $$$ at tune-up time.

My experience;
The installation was no problem for me, the telephone technical support from Jacobs was good, total installation time was less than 1 Saturday and 1 six-pack. After the mod, the ignition performance was fine and I did notice better performance with power & combustion, I really did not notice spectacular gas mileage improvement (hey, the bronco is a major gas-guzzler and I only get 12mpg on a good day anyway!!) - but I suppose there was some. The beast also passed emissions testing with no-problem after the mod.

Lifetime spark plug wires - well, lets just say that replacement wires have been very difficult for me to get from Jacobs. The first year, when one needed replacement - no problem getting that one. But, when I desperately needed a new wire last summer - it took 2 months to find someone in their warranty department. Turns out the original Jacobs company was sold out to another company and they were in the process of moving all of the services out of Texas. Apparently, the folks in Texas were none too happy about losing their jobs. I wrote letters, made phone calls (leaving messages on answering machines, all kinds of BS trying to get some service). I almost broke down and purchased a new plug wire - but being persistent and cheap - I jury-rigged an old wire to work until I could overcome the Jacobs Empire and get a new, 'free' lifetime spark plug wire. Eventually, I started getting (multiple) phone calls at my house (from the NEW Jacobs) asking if I got any help with my problem. I told them I needed a new spark plug wire - so they sent me a kit after I sent them copies of receipts and all sorts of other yak to prove that I was really me and that I purchased lifetime warranty wires from the old Jacobs. When I bought this stuff - they said I was registered in their computer system - but somehow they forgot about saving any information about people that purchased lifetime warranty wires. If you think the JEB is dead - no problem, just pull out the one installed in your rig, send it to Jacobs, and they will send it back later. Just call a cab while you wait for the replacement parts to arrive.

So, all was well with the beast until I went on a road trip last summer into the northern California & southern Oregon volcano lands. Man, it was HOT. Turns out that when JEB gets really hot - it shuts down until it cools down. So, unless you like being stranded in the California desert heat hiding in the shade under your Bronco waiting for night-fall - you should give special consideration to locating the JEB inside of a refrigerator. I have been thinking about designing a cooling plenium for JEB to make sure this never happens again - but until then - no more hot-summer-day-desert runs for me.

One time, I accidentally set the JEB maximum RPM limiter to ~ 1,000 RPM while timing the beast. (If you ground a pin on the JEB, then it stores a new maximum allowable engine RPM). Well, lets say I was really confused why the engine maxed out at 1,000 RPM after the tune-up. My brain was really hurting after I went through all of the machinations necessary to unfold the mystery and to correct the problem. I almost broke down and went to a mechanic - but my inner beast would simply not allow another man to mess with my outer beast. So now it is fixed and we are all happy and that much smarter.

Overall Ratings;
Parts (JEB & Ultra Coil) - 4 stars
Parts (connectors & plug wires) - 2 stars
Overall Performance - 4 stars
Technical Support & Installation Instructions - 4 stars
Warranty service - 2 stars
Reliability (on cool days) - 5 stars
Reliability (on hot days) - 0 stars
Satisfaction - ultra unmeasurable