i recently purchased a 1967 fairlane gt. it currently has a 289 in it, but i am opting to go with a big block. at first i was thinking of using the 390gt engine but after a little research decided that it wouldn't be too hard to use the 428 crank and make the 390 a 410. here is where i run into trouble. i understand that the 427 heads provide the best airflow but have trouble with valve clearance because of the 4.05 in bore. i've heard that the 390 gt heads are a good replacement for airflow and clearance in the vehicle for headers. is this true? what heads were originally used on the 410 and were they decent? also, what would be a good intake manifold? i don't want to sound like i have no original ideas. just looking for some guidance.