I myself use the magnum 257hp with a magna force 350hd it has 2 2879's, dead key set at 2 watts, works well and amp never gets warm. Open your palomar up and have a look at the transistors. If it's true high drive box, you should be okay like posted above, if it has the 1446 or similar transistors, the radio may have too much total pep power. I am not really familiar with MOSFET amps, like said, pull the cover off and see what's inside. It all comes down to the transistor type and the bias settings. My magnaforce 350hd is biased b and talks well for a 2 transistor amp with the 2879 transistors. Specs for mine stated up to 4 watts dead key with a 120 watt pep, my radio does 60-80 watts and it matches well with the magnaforce.
Take some photos of the inside and post them if you are unsure about what to look for. Hope you get it figured out, and make sure that you put a watt meter inline before putting the amp in and set your radios dead key for around 2 watts, mark it if possible with a silver sharpie. Saves a lot of headache trying to keep looking at the watt meter and driving and stuff. JMO and it's what I did to mine, and remember that the magnum 257hp works a little different on ssb and requires the power be set all the way up for proper operation, I have found that if the radio isn't right and I mean right as in tuned and aligned and set properly that your amp may go into oscillation trying to use it for ssb mode with the magnum 257hp. These are just my findings after using 2 of them for over 6 months now everyday. Good luck and hope this helps some. God bless .