Re: [VAC] Jacobs ignition system

["Dr. Gerald N. Johnson" <geraldj@xxxxxxxx>]

Its my opinion that air and exhaust flow improvements only help at very
high engine speeds. Most of the time the intake flow is restricted by
the throttle so freer flowing intake and exhaust only change the
throttle plate position. At full engine speed (my new Ford V-8 HP is
rated at 4600 RPM, quite a bit faster than I've run it) the flow
improvements may help.

I tried multispark ignition once, and while it ran OK, without drastic
carburetion changes it had no effect other than to wipe out the radio
with noise. I tried a Mallory pure centrifugal advance distributor once,
it worked fine at full throttle acceleration but killed gas mileage at
part throttle operation where more advance from the vacuum advance that
it didn't have was needed.

What did help my F-150 a great deal (manual transmission) is changing
the back axle gears from 3.08 to 4.10. Made it a hot rod. And it pulls
good too. I'll confirm that this weekend. Cost $480 at the local drag
shop installed. As far as I can measure the gas mileage has not changed.
By my computations it changed the trailer towing rating from 2200 pounds
to 4700 pounds.

One thing about the 302 is that its not a really tough engine. Adding
more HP through more fuel may lead to an early demise. Be sure and check
the fuel pressure regulator before it gets old. A broken regulator wiped
my 302 last winter.

Gerald J.