Quote:
Originally Posted by Bored&Stroked
There is nothing wrong with Chevy valves - they are a bit longer and the reason that I run them is due to the fact that I run very high performance cams - which means the base circle is a lot smaller than a normal setup. So - having longer valves helps take of that slack. Another reason is that I like some of the valve options for chrome stems, performance profiles below the head, materials, etc.. I have my own valve grinder, so I do massage them to achieve the profiles and head thicknesses that I desire. I usually run Manley Pro-Flow valves in most higher-performance engines.
There are other ways to deal with the issue of smaller cam base circles (and too short of valves in a stock valve situation) --> like using lash caps on the stock length valves. Or, running stock lifters and welding up the valve stems (like in the old days).
Regardless - if you're using adjustable lifters, the goal is to NOT have to turn adjustable lifter screws a long ways out (like you would with stock length valves and a high-lift cam). The reason you don't want the adjuster screws all the way out is that there are not enough interference fit threads to hold the adjusters in their original position -- what happens then is that they usually thread back into the adjustable lifter . . . making all sorts of valve noises and low-lift on the associated valves.
I learned all these things the hard way (40 years ago) . . . running a .450 lift cam with stock length 49-53 valves and Johnson lifters - they were always loosening up and I was constantly adjusting them.
Good luck - stick with it and you'll get it sorted out. You have a lot of "cooks in your kitchen" at the moment - hopefully you create a fine flathead meal as a result. 
B&S |
Yes B&S,,,,,,,,Totally agree with you.
Just to clarify,,,I should have stated, I see nothing wrong with using Chevy valves and quite a few flatheads out there are running them, but I would question the builder that installed them and what, if anything was done to the seats and where the valve springs came from. The crank gear and timing mark problems raise other possible red flags in my opinion.