if i had 1 OC ant @ 400 in stock Volt and one UC ant @ 275 with a 2.7-3.0 kOhms would i be able to run it with a 750 watt PSU
the OC ant would be around 360-400 watts and the UC would be like 150-160 watts
The wattage rating of the PSU is not a reliable guide.
You need to know how many 12volt circuits you have and what Amperage each circuit can provide. This has to be balanced across 4 x PCI-e 6pin connectors without overloading any one of the 12v circuits. An ant at 400Mhz is probably going to pull 17Amps per 12volt PCI-e connectors.