what should i set the timing at on my 78 f-150 with a 460 big block? thanks

 

I would set it at 8 BTDC. It will get you real close if it's stock, or close to it.

 

The stock rebuilt distributors (schucks, advance etc...) have no rhyme or reason to the centrifugal advance curve used. With a stock application running low C/R you want about 12 to 14 initial advance plus 24 to 26 degrees centrifugal for 36 to 38 toal degrees all in by 3,000 RPM. This will wake up any full emissions trim 460.

Here is a link to my site detailing how this is done: http://www.reincarnation-automotive....ons_index.html

The factory ignition curve comes in too late to do any good for power. The timing specs are more concerned with the 70's emissions mantra than any thing else.

Hope this helps...

 

I had mine recurved and was suggested by the shop to set the 460 @ 12* btdc. I've seen that listed as being sort of a "sweet spot" for the engine.

Roger

 

...centrifugal advance in the recurved distributor???

This will determine what your initial advance needs to be. There are 6 different advance slots in the BBF units. 12 degrees will not always be applicable depending on distributor set up.

The ideal is to have 38 degrees total in by 3K or a bit less depending on state of tune and convertor stall.

 

i had scott recurve my dizzy to his specs and it really woke up the 460 in my bronco

 

Actually mine was set up specific to my engine, transmission, axle ratio, trailer weight and air drag under varying conditions. This also took into account ground speed, engine rpm, engine vacuum readings, temperature, humidity, wind conditions and terrain. The recorded notes from two different trips were analyzed by the gentleman who did mine. He has ~30 years experience in his trade. He didn't even want to start it without this type of information.

I've got a sheet of information I received from him at home in the truck file, don't remember specifics. Before the recurve I was running at 12* based on personal experience and other information I had garnered from books and inet sites. He also instructed me to set the timing after the work at 12*.

Based on this I still think that *generally speaking* using a "one size fits all approach" 12* is a good place to start then tweak from there. I think that's what mud bug was asking for.

I do firmly believe having a distributor "re-worked" is important to good performance and money well spent. Rebuilts are notorious for having mismatched components. Mine was a Ford rebuilt ... ruined the original removing it at 39,000 miles and 12 years of never being touched. The weights were matched and close but were frequently sticking in full advance until almost an idle before they reset. I noticed the difference and Clyde handles the camper like I want it to.

 

If you will provide some additional information about your combo and distributor I can offer a better answer. Stock of mild performance??? etc etc...

Many of the late model dura spark distributors have a bunch of centrifugal advance built in. that when combined with too much initial advance can cause poor running or pinging.
Is your dizzy stock? Can you look at the link provided in my earlier post and let me know which advance slot is in use in your dizzy?

With this information I can give you a better answer.

The 12 to 14 degrees I offered as a suggestion is valid so long as the centrifugal advance in not excessive.

A properly curved distributor will make a world of difference in mileage and driveabliity for a small investment in time.

Hope this helps some...