Hey all, I have a 305 TPI with a crane cam, specs are 420i/442e, 262i/272e. I am still running the stock 1:5 rockers. I am about to pick up a set of summit 1:6 rollers. My question is, with the cam I have and the 1:6's will there be a clearance issue with my valve covers? If so, how much taller would I need to go? Thanks. James.

 

The cam won't make any difference as far as valve cover clearance goes.

Really depends upon the specific rockers you're talking about. Many interfere with the baffles in the covers more than anything else.

 

are you going to use poly-locks? These are rather tall locking nuts to hold the rockers. Most roller rockers require them, and if they are a problem, you may wish to find an extra-thick valve cover gasket.
Other rockers let you use stock-style rocker nuts, and I's suggest you go with Comp's Magnum toller-tip rockers. These will clear everything easily. If your heads have round holes for the pushrods, get the "rail-type" rockers, but if your heads have pushrod slots, use the "non-rail" rockers.
So-called rail rockers are self-aligning to the valve tip, so any pushrod guidance will cause binding and damage with these.

 

if you dont have self aligning rocker pre-86 heads you MAY have problems with the pushrod holes in the heads and having a little rubbing going on with your pushrods

 

My heads are the 416 castings, its an 86 motor. Here are the rockers by the way, http://store.summitracing.com/partde...7&autoview=sku

 

No problem at all. Basically the same thing I'm running under standard covers.

 

Awesome, thanks for the info.