Valvetrain questions?

[1972 DART]

I am building a 360 for my Dart. The cam is the 508" Mopar Purple Shaft hydraulic. The block and the heads were decked to give them a fresh surface. My question is will stock pushrods and stock shaft mounted rockers work because of the decking? Or should I get adjustable rockers or pushrods? I also read about the valve retainer hitting the guide on over 500" lift cams. If I run into this can the guides be driven further down into the heads or do they have to be cut? Thank you in advance, Bill

 

[moper]

Hi Bill, Welcome.
Were the heads done with an eye for performance, or just re-done stock, or not done yet? The issues with 360 heads are first the exh valves on most have a different spring retainer called a rotator. These valves and rotators should be discarded and replaced with std intake valve spring retainers and std exh valves. Second, the guides are tall and use the umbrella type seals. I dont think you'll have a problem with a .508 cam because after the factory rocker ratio and pushrod angle, if you actually have .480 lift at the valve I would be surprised. But if these are for a performance engine, I would have asked for the spring seats and guides to be cut during the valve job. At that point it's like $50 more. Doing it later is closer to $300 after cleaning, disassembly, cleaning, and reassembly.

 

[1972 DART]

The heads have 2.02/1.60 Manley valves with Comp Cams spring and retainers recommended for the cam. They didn't say anything about the seats or guides being cut. I guess I can visually check for clearance when I assemble it? Do you lose some lift with stock rockers/pushrods?

 

[moper]

Look at the valve springs and seal first... There are three types you might find: Stock springs that have a single would wire (Comp's generally will not be these). Second is a high performance general use spring, which has a single round wire plus a flat wire inner dampener (you can see the flat metal winding...) Third are higher performance dual springs which have the round outer wire spring, then the flat wire dampener, then a single smaller round wire inner spring. The second type can use either type of valve seals I mentioned. Umbrella type seals are factory and are large and black. They will fill up the spring. Positive seals are smaller and usually white or gold in color.