which motor mount insulators, 64 dart 273 V8

Link to the ones you're referring to?
Beware- in many places (including parts stores, both brick & mortar and online) the thin ones (2266) are being incorrectly listed as being correct for the '66 and earlier A bodies. They aren't! Those are for '67-'72, and their use on early As can and probably will cause various clearance issues (oil pan to tie rod, exhaust/header to t-bar, manifold/header to steering column, etc.), necessitating the use of additional spacers to get things lined up correctly again. The correct mount is a number 2338, Which seems to be getting harder to find, at least correctly listed. The common replacement is either a 2469 (mid '80ish Dodge truck V8) or the 2710 ('90ish Cummins diesel) which both have the interlocking fingers and negate the need for a torque strap in high performance applications. They are both thicker than the 2266s, and nearly identical in thickness to the 2338, with the 2710 being a hair thicker than the 2469.
2266:
602266_1__ra_t.jpg
2338:
2338-001__ra_t.jpg
2469:
EM-2469__ra_t.jpg
2710:
602710_1__ra_t.jpg