MSD 8577 / 6a to Vacuum Advance Distributor

[cycleguy55]

My 460 is currently running a MSD 8577 with a MSD 6a box (p/n 6200 - one of the older ones). I'm planning to swap out the distributor and install one with a vacuum advance.

Right now the two leading contenders are: a) MSD 8477 (same as 8577 with vacuum advance); and b) the all-in-one Summit HEI distributor (http://www.summitracing.com/int/part...0025/overview/).

The MSD should be purely 'plug and play' other than timing adjustments, while the Summit looks like it does not need the MSD box, and I'd obviously need to re-wire the tachometer feed, but that seems relatively trivial. The MSD is $213 more than the Summit, but spending the money is an easy decision if that's the better route to go.

Am I missing something? Are there other things I should consider before making the decision and pulling the trigger? Other distributors I should consider (and reasons)? Has anyone done a similar conversion such as: a) mechanical to VA distributor; b) removing MSD box; or c) all of the above?

[mdross1]

Our car has had a Mallory Unilite for the last 10 yrs. Only thing I changed was centrifugal advance springs to get the advance curve to be full in by 2000rpm. There are a few good choices.

[cycleguy55]

Originally Posted by mdross1

Our car has had a Mallory Unilite for the last 10 yrs. Only thing I changed was centrifugal advance springs to get the advance curve to be full in by 2000rpm. There are a few good choices.

Interesting. I did some Web surfing last night and it certainly seems there are many satisfied Mallory customers. It seems many report fewer internal corrosion issues with Mallory, though changing the advance is more difficult and changing the sensor / pickup module is easier (and apparently more frequent).

Looking at the Mallory Promaster 8350M (http://www.summitracing.com/int/part...view/make/ford) it appears very similar to the MSD 8477, though Summit indicates the Mallory does not need an external ignition box. Having one already installed, though, I'd obviously like to use it, and it is my understanding the Mallory may be fully compatible with the MSD 6A, even plugging into the MSD distributor connector.

OTOH, with MSD acquiring and merging Mallory into the MSD product line, future support for MSD may well be better than Mallory. The MSD 8477 is about $100 more than the Mallory 8350M, with a rebate of $25 until the end of August, so it may be money well spent.

[mdross1]

I hear you we all make the choices that best suits us. The very reason why our cars are all so different. I ran the Dura Spark for a few years it too worked great just wanted a smaller distributor. Whatever we choose as long as they are set up correctly the brand name products cannot be beat.

The vacuum advance in the Mallory is blocked off. Lately most of my driving is quite aggressive so it is not needed.