HI SLADE,
AS BILL SAID, THE THERMACTOR / NON-THERMACTOR IS THE METHOD USED TO DETERMINE WHICH DIZZY ORIGINALLY CAME WITH THE CAR. AS FEW OF US ARE RUNNING ORIGINAL EQUIPMENT VEHICLES THIS METHOD OF DETERMINING THE CORRECT UNIT FOR YOUR CAR MAY NOT WORK (PROBABLY WON'T). FOR THE RECORD IT IS THE DISTIBUTOR DRIVE THAT MAKES THE DIFFERENCE. ONE OF THE PERTRONIX UNITS FITS THE DIZZY WITH A "D" SHAPED DRIVE, THE OTHER FITS THE DIZZY WITH THE SLOTTED DRIVE, I.E., IF YOUR ROTOR HAS A KEY IN IT YOU NEED THE PERTRONIX UNIT FOR THE "C" / SLOTTED / KEYED DRIVE. I DON'T REMEBER WHICH IS WHICH NOW (THERMACTOR OR NOT), BUT PERTRONIX IS VERY GOOD ABOUT TAKING TECH CALLS. AS A MATTER OF FACT, THEY EXCHANGED MINE FOR ME WHEN I DISCOVERED I HAD THE WRONG ONE.
AS FOR THE DIZZY IN YOUR CAR, I HIGHLY RECOMMEND THE DUAL ADVANCE UNIT (VAC + MECHANICAL) AND CONVERTING TO MECHANICAL ONLY SYSTEM. THIS TOPIC HAS COME UP IN A NUMBER OF IGNITION POST, BUT IN YOUR CASE, I SUSPECT YOU WILL NOT GET THE BEST OUT OF YOUR TRI-CARB SET-UP TRYING TO USE A VAC SYSTEM (SINGLE OR DUAL). THE CONVERSION IS VERY SIMPLE, BUT YOU WILL NEED TO START WITH A DUAL ADVANCE UNIT. PM ME IF YOU WOULD LIKE MORE INFO. I USE THIS SET-UP ON MY CAR. I BELIEVE THERE ARE SEVERAL OTHERS WHO HAVE MADE THE SWITCH.
LOOKING FORWARD TO HEARING MORE ABOUT YOUR CAR WHEN DONE. MAJOR UNDERTAKING. MAY TAKE A LITTLE TIME TO SORT OUT WHEN DONE, BUT, THERE IS A VERY SIMILAR TRI-POWER CONVERT HERE IN SO CAL I HAVE VISITED WITH SEVERAL TIMES AND HE IS QUITE CONFIDENT HIS CAR MAKES 180+ HP (USES MECHANICAL ONLY DIZZY - I GOT THE CONFIDENCE TO TRY IT FROM HIM).
STEVE
