crane timing retard control ignition question.

i have crane hi6 trc ignition on a 6 triggered by a standard hei bosch distributor. i guess its simular to the MSD 6al btm.
the standard bosch electronic module is removed and the trigger wired directly to the hi6.
i have a blower now fitted with a single SU 2" carb and want to fit the optional map sensor and timing retard control.
do i
a) leave the vacuum advance and mechanical advance standard and wire up the hi6 trc with
the map sensor?

b) lock the mechanical advance, block vacuum advance, advance the timing and let the map sensor retard
the timing with the trc controller?

C) get the distributor regraphed to suit cam & blower and keep vacuum advance?

 

You will likely get different opinions on this and alot will depend on your particular motor set up compression ratio amount of boost etc...
On mine (MSD6btm) I dont use the VAC advance and I recurved the distributer to have only 12* of mechanical advance. My initial timing is set at 22* and by 2500 rpm is at full advance of 34* then the BTM pulls timing out from there while under boost conditions. But it can be done succesfully other ways too. Locked at full timing with no Vac advance or using the Vac advance and mechanical advance too. Blown motors (in my experience) typically like alot of initial timing and fine tuning the timing can greatly affect the performance. More than likely recurving your distributor will be needed to achieve the best results no matter which way you end up doing it.
Maybe Squirrel will chime in here he would be better to explain it than me
and Im ***umng the Crane set up works like the MSD BTM box.

Do a search there was a really informative thread about this not too long ago.

 

i did a search and read this- http://www.jalopyjournal.com/forum/showthread.php?t=412468&highlight=boost+timing

i am still confused, i thought maybe i could lock the mechanical advance and just rely on the crane hi6 trc with the map sensor.
that would save $$$ on getting the distributor regraphed and i could do it now.
do i just leave vac adv, mech adv and the trc to all adv and retard the timing at once?

the car currently runs ok with vac advance with no pinging, the reason i want to wire up the trc and map is becuase i am going to change from 4 psi to about 12 psi