I say it is the passenger side motor mount but you should replace both of them and not just one if it is your problem.

 

Motor mount. Mostpeople think this isn't an issue with 6's, but actually it is a bigger issue with aggressively driven 6's than v8's due to the design on the motor mount. This also makes it harder to see the problem. Jack up the motor and pull them out. It will then be obvious if that is the problem

 

+1, but it going to be the drivers side motor mount.

 

like some1 said before, if you replace one replace the other. LH and RH should be replaced in unison

 

well im getting 2 new motor mounts and a tranny mount just to make sure. im pretty sure now that it is my driver side motor mount. and thank you everyone for your help. the "grinding" was my oil breather cap. thanks again.
i have a 351 cleveland that is going in it in about 6 weeks when i get enough money to finish it. =D i found a 4 speed that was in my buddy's attic and i might get that or just build up my c-4. i dont know yet. whenever i get the money. which is better, a ford 9" or an 8" rear end. both being posi. i think 9" but it is heavier so im not sure if an 8" would be good

 

k got it thank you