408 Valve train noise??
Type: Flat Tappet
- .474 Intake .474 Exhaust
233 Intake / 240 Exhaust duration
@ .050 - 110 degree lobe separation
Hydraulic or solid flat tappet?
As I understand they are magnum heads on an LA block.
Sounds to me like pushrod length may be suspect.
If you have a solid cam, you're trying to run it with a non-adjustable valvetrain. Custom length pushrods are required with this setup, but no matter how carefully you measure, you need adjustability built in to dial in your valve lash.
If you have a hydraulic cam, your pushrod length is critical with a non-stock head/block combination; if too short the lifters never achieve adequate preload, if too extreme you run the risk of the lifters coming apart.
Is this something you pieced together from a crate short block and Mag heads, or did you purchase the entire engine assembly? Reputable builder or EBay special?
