I’m pretty sure you can use the stock Hemi rockers with 36lb springs. I think that is what I have right now.
If you go with NR Racing’s Hemi rollers, then you’ll want shorter pushrods. I think all roller rockers need shorter pushrods, but I’ve only used NR’s. Since you say you have 36lb springs I imagine you already have had the spring pockets cut to accept the larger diameter springs.??? Is the head milled as well? Thinner gasket and milling affects the length of the pushrod needed as well.
I’ve used an aftermarket valve cover on my build using the roller ratio rockers, but I wanted it for the looks. However, I’m pretty sure there was interference with the stock, unmodified vakve cover.
There are spacers to use with the stock valve cover, or a few sellers make taller ones that work fine. Or a dremel to the inside of the valve cover can probably give you the clearance you need. Jody from ARC has a video.
If you do use roller rockers, do you have enough piston to valve clearance? A 308 cam with 1.2 rockers is about 0.370”. Have to check for coil bind (especially on the exhaust side) and piston to valve clearance.
Call ARC and ask for Jody. He’ll get you straightened out if you can’t get hold of Russel at NR.
Or if on FB, you can shoot ARC a message. They always respond promptly to me and give great support. I’ve tried to learn as much as possible about these engines, but I’ve only put 3 Hemis together. So my knowledge and experience is limited.
https://youtu.be/QuKsRRrDeXk
