The Fast Burn, Vortec Bow-Tie style aluminum heads on the ‘604 are excellent flowing stock heads.
Unlike the heads on the ‘602 & ‘603 crate motors, which improve tremendously with “UnderCover Porting“, this head will not benefit from “UnderCover Porting” type modifications.
604 Bee Hive Springs
Upgrade Kit #1 : Like most mass-produced factory engines, the valve train is the weak link on the Chevy crate motors. Our 604 Bee-Hive valve train Conversion/Upgrade Kit uses better fitting, longer lasting aftermarket Look-a-Like Bee-Hive springs, retainers, locks, spring locators & 16 original GM valve seals giving you a bullet-proof valve train for your 604 crate. (This kit converts the older style, NON bee-hive parts to the bee-hive parts.) – $449.00.
Upgrade Kit #2: Upgrades your current GM Bee-Hive crate parts to aftermarket Look-a-Like Bee-Hive springs, retainers & locks. (Includes everything in Kit#1 except the spring locators and valve seals) – $395.00.
Early Style, Non-Bee-Hive “Look-A-Like” Replacement Valve Springs
More horsepower and eliminate the valve train breakage, which was common with the early style non-beehive ‘604 springs. Same wire & outside diameter as the stock springs and have a green stripe. They will last a few thousand laps vs. a few hundred laps for the stock spring. $349.00 set of 16 springs.
Our Crate Master camshafts are ground on original Chevy camshaft cores. The duration and lobe centers are changed; the valve lift is the same as stock. If you want to wake-up a ‘604 crate, change the camshaft. New Crate Master ‘604 camshaft – $525.00