The person that built my 727 said that he would not guarantee it if I used a Lokar linkage. It simply don't provide the correct signal to the downshift lever to keep line pressure at the proper level.
As far as timing, I can see using more initial advance, but you must keep total advance to about 34° for a LA engine or you will lose power and risk detonation. The higher spark plug location in the LA chamber makes the flame front start from a more central location shortening the travel to the cylinder wall. Thus less timing needed for max power. Too much advance can lower power at full throttle and lead to detonation. All bad.
I also adhere to the advice of Rich Ehrenburg of Mopar Action. Double Pumpers are for race engines and have no place on the street. I learned this myself when much younger than now. The DP sucked fuel and will lead to increased cylinder wall wear and fuel dilution in the oil.
