Camshaft choices

[cadillac512]

The Zephyr springs are just a bit higher pressure...not much but they install same as stock and won't be hard on parts.

The rotators are just a different type retainer setup that allows the valve to turn slightly as it operates. The idea is to help reduce hot spots on the valve faces due to carbon buildup and to provide more even wear. That style was used on the last years of engines and uses a shorter spring than all earlier models.
Personally I don't think the rotator type have any advantage over the earlier type. They are not a positive rotation type like some modern OHV engines have used. Modern fuels have much less carbon buildup as well, lessening the need.


Terry

 

[hotrodcbx]

I agree with not needing a 9-inch. As a kid I did terrible horrible things to the 8-inch in my '65 Mustang and never broke it. That was with a stock 289 with 200 horsepower and wide tires trying to do burnouts. I doubt that a flathead could hurt an 8-inch. All the extra weight and gear friction from a 9-inch is just going to suck up your power.

Depending on your tire diameter the 3.55 gears are perfect. I had Mustangs with 3:00.1 and they sucked for acceleration. My ''66 GT-350 has 3.89s and it whining away at 70 mph and not comfortable to drive. I had one Mustang with a 9-inch with 3.50s and that seemed to be the happy spot for good acceleration and freeway driving.

I Looked up the diameter of your 225-70-15 and its 27.4 inches, exactly the same as the 7.75X15 Goodyear Blue dots on my Shelby. That car is a little uncomfortable to drive on the freeway for long periods with those gears It's fun for short drives but you would not want it as your daily driver with 3.89s. I think you will have fun with 3.55s. The rpms on the freeway will be higher than your use to with modern overdrives but its the best compromise between fun acceleration and freeway driving.

I use a 8" in my blown 3 window with no problems. It is 50 lbs lighter than a 9" and takes less HP to drive it. CAUTION: Do not use a early 8" which is readily distinguished by a lack of reinforcement webbing in the center housing. The hp version has heavy webbing, not smooth like the early one. Ask me how I know? I still have wall art in my garage of what once looked like a center section!
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