Can I run a standard Felpro 1275 intake gasket on my 500efi or do I need to run the Felpro 17342 does anyone know the difference ?

I think I put the 17342 on mine, 26 bucks on ebay

the 1275 has 6 bolt holes, the 17342 has 8 holes,either will work but with the 1275 you skip the 2 bolts on top .

1275 is for dart heads I believe, they dont have the "dip" between ports.

dip between ports?if you mean the area near the xtra bolt holes that only the gm heads have that is because dart,afr brodix,etc only have 6 bolt holes.

you really want the 1275S-3 cored and with print seal, does not have the middle holes. Your plain old 1275 tends to leak as it's not a cored gasket, only good for about a year, then comes the milk shake

yep