Mike,
The studs put more clamping force on the main caps. That is really the reason to use them. By clamping tighter, they will sometimes distort the cap enough to require align honing. To be honest with you I feel this is something that should be done on any serious perfomance engine anyway. If you were to bolt the main caps on a "perfectly good" block and measure the bearing bore with a good bore gauge, you would agree with me. We do it on every performance motor that we do, it is not an option.
If the block was align honed, you really should not need to replace the timing set with a shorter one. This is usually only needed when the block is badly damaged from a spun bearing and has to be aling bored, not just honed.
As far as RPM on the rat, I would not go much more than 6400, depending on piston weight etc. With stock weight parts this is plenty. Besides with a 454 it makes so much torque and power in the low and midrange that you are really wasting your time spinning it much higher. This is all assuming stock and mild performance parts.
Hope this helps,
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Bill Koustenis
Advanced Automotive Machine
Waldorf Md
1971 Heavy Chevy - original owner
Team Chevelle #100