my 408 build

moper said

They sold the right springs to you...lol You just ran stock length valves...lol. It's common to cut the spring seats down, or use .110" longer valves, or a combination of those with tall retainers to get the required installed hieght. I always consider it a mild risk not using what the manufacturer spec'd, but, going slightly heavier should not hurt it so long as you break it in properly (without the inners) and use a good oil. These will definately be able to run way into the 12s in a street A body with these setups and properly matched drvielines.

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The machine shop told me that cutting the spring seats down by .100 was too much. They did end up cutting them .020 or so to use the springs I ended up with.

I did not think much about it until I was reading the Mancini Racing flyer and saw the Comp Springs they had for sale. I looked up the specs on them and realized they were double springs that were sized to fit on Mopar with stock val;ves and they cost the samme as the springs Comp Cams had included in the kit. DUH, if they make springs that fit the MOPAR why not recommend those for use and include them in the kit???

Guy at shop told me they had the same issue with a Buick engine using Comp cams kit just recently, and it happens all the time.