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Old 04-29-2019, 03:45 PM
fastsr20det fastsr20det is offline
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Default Roller rockers help

So I'm trying to change my roller rockers that is the last thing I need if I have to change them I need help on what to get. I have cm push rods(standard), 308 cam, 36lb springs, billet lifters, standard SS valve stems, cm lash caps flat top piston, .010 head gasket. I know there are some rockers that you have to modify have the valve cover or something like that which is fine but if I dont have to that would be nice.i have a hemi predator 212..please help yall thanks you guys for all the help kinda new to this so I'm trying to make this build right.
Old 04-29-2019, 06:40 PM
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Joe-405 Joe-405 is offline
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Bob know all..........he be answering shortly.

I been out of the predator engine game too long as I been using bike engines lately. But it sounds like you got everything I would think. You could also call NR Racing. He’s a super big help when I did my last one.
Old 05-01-2019, 08:33 AM
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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.

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