Chevy 603 Crate Motor Performance

More Power for Your ‘603 Crate

'603 Crate with "UnderCover Porting".

The stock intake port flows just 188 cfm – that is worse than stock “double hump” heads. With our “Undercover Porting” the intake air flow is improved to over 218 cfm and the port still looks stock!

Unlike the ‘604 Crate, which has excellent cylinder heads, the heads on the ‘603 Crate are just plain awful from a performance standpoint for anything over 5,500 rpm.

If you want to get a huge advantage over the car next to you, get your heads “UnderCover Ported“. Or, don’t get them modified and run just like the rest of the pack.

“Undercover Porting” and Update YOUR Complete ‘603 Heads

Send us YOUR complete new or used ‘603 heads. We will take them apart, perform our “Undercover Porting”, surface the heads and assemble them with our “Look-A-Like” intake valves, valve springs, retainers and locks. Cost is $1,895.00 to rework YOUR complete ‘603 heads.


“Undercover Porting” to YOUR Bare ‘603 Heads

Send us your new or used bare ‘603 heads. We will perform our “Undercover Porting”, which includes CNC machining, modifications to the intake ports, exhaust ports, combustion chambers, “Cover Up” work, sizing the valve guides and machining the valve seats for 1.94″ x 1.50″ valves. Cost is $995.00 labor only to your bare pair of ‘603 heads.


"Look-A-Like” Replacement Valve Springs: More horsepower and eliminate the valve train breakage. They look like the original springs, have more spring pressure and last a few thousand laps vs. a few hundred for the stock spring.“Look-A-Like” Valve Springs
The stock ‘603 springs go away after a few hundred laps; Our “Look-A-Like” springs will last a few thousand laps. They look like the original springs and have a bit more spring pressure.

#603S – 16 “Look-A-Like” valve springs for the ‘603 Crate Motor – $349.00.


dscf0926_000Look-A-Like” Retainers
No more retainer breakage with our chrome moly retainers! Same look as the original retainers and a lot stronger.

#603R – 16 “Look-A-Like” retainers for the ‘603 Crate Motor – $100.00


It is tough to take a good picture of valve locks. So, we don’t have one. But, we do have machined standard height , -025″ & -.050″ Look-A-Like locks are in stock.

#603L – 16 Look-A-Like locks, $65.00        


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.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.

#603CAM3 – New Crate Master ‘603 camshaft – $525.00

See also: Cylinder Head Resources

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