6 Liter Tune Up Loss of MPG

miles315 said:

Also would skipping be the reason for my MPG dropping? I feel like I would notice it in how the engine runs, but it seems like it runs fine. Should I just go back to stock gap or maybe just decrease it to .05-.052?

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If you're not going to bump the timing, return the gap to the factory spec. By running a larger gap, and not increasing anything else, all you're doing is mimic-ing a motor with worn out spark plugs.

miles315 said:

Like user Jermil said, the 6 liter may have only been designed for the 302. Is there any benefit for doing it in a 351?

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I did the 6Liter on my '86 351 Bronco, and it's night and day better. Starts up better, and a little more power when cruising. The initial throttle tip-in response is far more reactive, she's a peppy truck at 13 degrees BTDC. I will absolutely do it to any other one of these old trucks I buy. It did help that when I bought mine, it already had the MSD coil and 6AL ignition box.

RustProof said:

Never used an MSD but I've heard they arent that reliable. the factory system seems pretty good. I just keep a spare TFi module just in case, but I've never had to use it to date

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Knock on wood, the MSD stuff in my Bronco has been flawless. I've had the truck for 3 years, put 8k on it, no concerns at all. The MSD coil and 6AL box were on it when I bought it, and they've been on it for years. Perks of buying it from someone you know, you get a little history.