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I am building a 400 sbc using a solid roller and a new set of AFR 220 heads. The heads come with 1.550 springs installed and my open pressure will be around 580 or so. This will be street/strip so I originally wanted to use a steel rocker... I was looking at the comp cams ultra pro magnum XD rockers. Listed as good for 1000lbs over the nose, however, not sure if they will clear the 1.550 spring/retainer on the AFR heads. Anyone have any experience with this set up? Any other rocker recommendations? Thanks
 

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I am building a 400 sbc using a solid roller and a new set of AFR 220 heads. The heads come with 1.550 springs installed and my open pressure will be around 580 or so. This will be street/strip so I originally wanted to use a steel rocker... I was looking at the comp cams ultra pro magnum XD rockers. Listed as good for 1000lbs over the nose, however, not sure if they will clear the 1.550 spring/retainer on the AFR heads. Anyone have any experience with this set up? Any other rocker recommendations? Thanks
It’ll be close, and I’d say you’ll have clearance issues. Why they even make something that won’t clear a normal sized spring is beyond me. But, I may be wrong. I’d call tech. I know they don’t come close to clearing a 1.625.
 

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Harland Sharp and Scorpion must have used THE Foxwell design I suppose then.
Used both of these on that head with no problems. 1.6 HS and 1.8 Scorpion with .100 long pushrods.
 

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I have the exact same setup, and they hit/rubbed 1.55" retainers with a .100" longer than stock pushrod. Bought the Golds from Competition Cams and they had plenty of clearance.
 

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Discussion Starter #10
I have the exact same setup, and they hit/rubbed 1.55" retainers with a .100" longer than stock pushrod. Bought the Golds from Competition Cams and they had plenty of clearance.
Yea, that's what it looks like. Gunna go with scorpion or HS.
 

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Rocker to retainer interference usually comes from not having the rocker geometry right and too short of a pushrod. Whatever rocker you choose, check the geometry. This might help with that;
 

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Nice video Scott.
This mid-lift procedure (minimizing sweep pattern - not centering) is explained quite well.
Solves the valve side of the geometry.
I have heard from some others - R. Malik - that push rod side geometry is as important or more important than the valve side geometry.
I would expect that some rocker arm designs (manufacturer(s)) have a better than others push rod side geometry once the valve side geometry is set.

Cheers
 

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Nice video Scott.
This mid-lift procedure (minimizing sweep pattern - not centering) is explained quite well.
Solves the valve side of the geometry.
I have heard from some others - R. Malik - that push rod side geometry is as important or more important than the valve side geometry.
I would expect that some rocker arm designs (manufacturer(s)) have a better than others push rod side geometry once the valve side geometry is set.

Cheers
Thanks. I agree that the pushrod side is important and the big block rockers that I developed with Sharp got corrected on both sides...pushrod and valve. Unfortunately we can't always do much about the pushrod side. Since there is a lot more "movement" on the valve side and it's much more dynamic, I think if you have to choose, it's best to get the valve side geometry correct. A loss of geometry on the pushrod side may have a dynamic effect but I don't see it having a damaging effect like poor geometry on the valve side can unless it's just really bad- like tossing a pushrod bad. Also have to remember that the geometry on either side is only "correct" for one specific lift. Anything either side of that is a compromise so this is definitely a game of "close enough".
 
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