dist. mechanical advance ajustment?

j.d.duggan said
pretty much stock 340,bought new spectra premium dist.trying to get some fuel mileage out of this thing and think vac. advance will help.I have msd box,if it maters.my engine likes to start and idle at 10* btdc.The dist. I have is a ch04,spectra #.the problem is,it has 30* of mechanical advance in it.trying to keep my total to 34*,I have to set my initial at 4*,does not like this for starting.my vac. can on this dist. has 22* in it.I think if I could set my total mech. adv.to 24*,then set my initial to 10*,I should have 34 total and 56 cruising.Am I thinking correctly? If so The real ? is how to limit the total mechanical to 24*:BangHead:

Just to add a little, you can get that limit plate directly from Don at www.4secondsflat.com for 22 shipped.
They are his product.
When I need one (I do them for other people) I just Paypal 22 even to sales@4secondsflat.com and in the notes on the payment put in "Chrysler small block timing limit plate" and the shipping address.