I'm thinking I'm real close to the max travel on the stock stamped steel rockers that are on my 5.7 SBC - I'm running the XM270H cam with .480/.489 lift and from what I've read the stock rockers are good to .460 or .470 lift. In turning the engine over by hand it doesn't bind or hit, but I don't have a good way to check for the .060-.080 clearance between the slot and stud so I was just going to swap to some roller rockers instead of long-slot stamped rockers. I'm looking for a recomendation on what rockers fit without changing everything else... (width to clear and height clearance)

I'm running stock "Centerbolt" valvecovers on it and don't think I can clear tall valvecovers with the stock exhaust manifolds on there and really don't have the funds to swap the exhaust for some headers right now just so I can run a taller valvecover...

Also - would using a set of 1.6 rockers cause reversion problems if it's currently "on the edge" of reversion (don't know for sure but this is the biggest cam comp recommended for stock manifolds and I'll check when I get it in the water) - I know the lift will change to ~.512/521 and the spring setup is good to ~.550 lift and .58x coil bind if I remember right so I should be OK there.

Camp Pro Magnum with Mr Gaskets Ultra-Seal Extra Thick valve cover gasket and they fit and do not hit .

WOW - that's a nice looking engine - those valvecovers look like aftermarket aluminum ones - I called comp before posting and they said that the pro-magnum's won't fit under the "Stock" valvecovers - actually I think it was more because of the breather baffle between the two cylinders where the PCV goes - does that valvecover have the ~1" wide baffle that is under where the PCV/breather goes?

Yes it has the baffle and you can get the Valve covers from Jeg's or Summit for about $90.00 a set.

I used summit racing aluminum full roller self aligning narrow body center bolt valve cover rocker arms part# sum-g6935-16 running a comp cam xm270hr with stock valve covers and didnt have any clearance issuse.

Crane makes a set of narrow body self aligning rockers as well. I had them on my old 350 when I still had the iron centerbolt heads and stock valve covers. I don't recall the part number but they are the Crane Gold Race rockers.

I know this a old thread how did you like the stainless steel marine manifold/riser set up ? Power gains ? ease of installation, access to spark plugs ?

Yes I do like them, We put them on our 515's 600hp and never looked back.

Did the valve covers clear the SM manifolds ok?? Sharp engine!

Yes they did, With the valve covers we used and the thick gasket you could take off the valve cover without removing the manifolds.