As we all know, the major hurdle for the 455's is low compression and non adjustable valves. I had my blocked decked .045 and was wanting to use a set of stage1 heads that had already been shaved .010 on my race Skylark. I was concerned about piston to valve clearence at high rpm due to the valves now being .055 closer to the pistons. After pricing adjustable pushrods and rockershafts, I decided to attempt another solution. My first attempt to run the engine resulted in 5 bent pushrods and a broken rocker shaft when I got the engine over 5000rpm. I was using Poston's 110 cam by the way. After deciding to go ahead and go the extra money, me and a friend came up with a solution. We miked the snap rings from the old lifters (Rhoades) and discovered they were .037 thick. I checked the new lifters (Poston Hi-revs) and discovered the snap-ring channel was plenty large enough to accomidate the additional snap ring. We installed the snap rings in the new lifters and now the motor turns 6500 with no problem. Let me know what you all think, I can see no adverse side-effects by merely limiting the travel of the plunger. This is a free modification when changing cams as most people don't re-use lifters anyway. Also you don't have the extra weight of the adjusters on the pushrods causing valvetrain wear. It was definately cheaper than new pushrods and high compression pistons to achieve the same results. :beer
Good information and advice. It's probably a good idea to take "shortcuts" like this when you get the opportunity and chance to do so, if you can save yourself some money and get the same results, why not, right? :bglasses:
