Heres what Ive got:
355cid, 200cc Toplines, XR282HR-112*, 10.3:1 static

Ive already got Comp 986 springs installed (at the proper height) but Ive had some second thoughts. I plan on a maximum rpm of 6500-6800, will the 986s control valve float in this rpm range? Comp recommended the 986s, but Ive heard of people having trouble with float at higher revs with these springs. Would the 987s be better for my application?

 

Depends on a number of things, including rocker ratio and retainers.

The 986s will control the valves better around the seat, especially if the cam you use is real low lift (below .550"). The 987s will tolerate a bit more lift.

I ran 986s with that same cam and 1.6 rockers, that combo worked fine for me.

 

Well Im using 1.6 ProMagnums, so that puts the effective lift at .544/.555. Thats right on the border I guess. Im using 10 deg. locks and steel retainers.

 

I used their better roller rockers (part # 1102) and it all worked fine.

Make sure you check you push rod length. Stock ones will almost certainly be too short.

 

I figured that my pushrods would be way off stock length, but the engines at the machine shop and isnt assembled enough to measure them yet. I suppose the situation is only complicated more by the excessive height of the Topline heads. Thanks for the advice.

 

I think you will float the valves at Rs with the 986s.

Ti retainers will help serve your cause, ~130$ though. My buddy just scored a set and damn are they light compared to the steel ones, multiple times lighter, its sick.