XE264HR/XE258HR Piston to valve clearance

[fishinman78]

I have been reading threads on these two cams:

XE264HR and XE258HR. I have a 351w with stock pistons and I am planning on running one of these cams with Ford Racing X306 aluminum heads. I am not especially savvy on cams so I wanted to find out for those that have installed either cam did you run into any problems with piston to valve clearance?

 

[nvrstuk]

Need more info...

-how far are the pistons sticking out of the block
-what thickness head gasket are you using
-what ratio rockers are you using (stock or ?)
-stock pistons ? what block '69 or '70 model?

 

[Amac70]

i run the the 258 with stock flat top pistons stock bottom end 96 roller block and edelbrock rpm heads with 1:6 roller rockers I clayed the valves and had plenty of clearance with flat top pistons.

 

[latrucker]

You can put clay on top the piston to check PTV clearance but neither one of those cams have enough lift or duration to be a problem. When a cam has valve overlap (choppy idle) is when PTV clearance becomes a problem. I ran the 258 with flattop pistons and .005" piston to deck clearance and had miles of clearance. I think you will be fine either way. Do your homework but that is my .02 cents.....