info on 638

[Dunbeck92]

Ive been esearching more about different engines to put in chevelles and i wanna go big or go home. i wanna eventually build a 638 from the ground up. are there any manufacturers that sell just the bare block? and where would i go for headers? i was looking at hooker but i didnt know if i needed to get higher performance since most of the ones on there are for small blocks and 454. thanks for the inputs