This simple info seems a little spotty to find and I try to research a little bit before breaking out the grinder. The first engine I built had Crane 'Gold Race' 1.5 $$ narrow body roller rockers that fit under the stock centerbolt covers with no issues. My current engine uses Comp 1.6 stainless steel self align roller rockers that have a wider body to them. I'm not much for spending money on 'show' so I wanted the stock covers to work if at all possible...and they did including the full length poly locks with guide plates. It took about 45 minutes for the pair to cut one brace out X 8 and contour the remaining brace. With a vise I had to squeeze the baffles about 1/4in. Works great and the price is right. PS, I was looking for LT4 and LT1 plastic rocker covers (good luck)- but this works for any truck rocker cover as well after selecting the pcv/vent/oil fill configuration you want to run.

So, you have pro magnums correct? And that's all the trimming you had to do? Seems easy enough, they don't leak or anything now?

It's been awhile.
The rockers are Comps older style steel bodied self aligning full roller rockers- even so there was enough slop, that the machine shop still installed the guide plates. Works great. Also I run RHS Vortec heads and a Edelbrock TPI set up which requires an external Corvette style EGR tube pulling off the passenger rear header- which didn't allow the use of taller aftermarket valve covers without rewelding the tube- works for me and cheaper.

Did you do all the mods at the same time? Or did you install the roller rockers separately, if so did you see any decent gains?
I wanted to do comp cams ultra pro magnum roller rockers, the updated version of the pro magnums. And I just bought new stockers that have been chrome plated and I got a sick deal for them. I just want to make sure if i buy roller rockers that I can run them with these valve covers...

If you're buying these for hp gains- put your money into something else. I bought for friction reduction- lowers engine temps, easier on the valve guides too, will be noisier. Mine are 1.6 to add to the cam. You'll have to talk to CC about the newer fitment- the only r rockers I know to fit without mods are Crane Gold Race $$.

Been thinking about it. And don't think roller rockers will give much gain on a bolt on engine...

Don't get me wrong- you see many rr applications (factory LS) because they work and are popular. You just need to understand where they fit in for effeciency. Only buy good quality and be aware of what happens if they fail. I would say the Crane Gold Race are way overpriced- with this mod it may even allow you to use regular sbc r rockers which are cheaper again.

I was gonna go for the pro magnums, but theyre discontinued. So my sights went on to the ultra pro magnums, and they are $373 cnd, so i'll just do my intake swap, headers, ypipe, tune, cai, and that stuff. Roller rockers wouldnt give me much on a stock engine with bolt ons anyways.