Any input on what shaft mounted rockers to use?

[zrayr]

Originally Posted by Mark O'Neal

".................
If you're not racing it, what do you intend to gain by changing what works well already.

If you are racing it....consider a stud girdle.

a big block Ford engine will turn over considerably easier by hand than a small block. The difference is the increased friction of the small blocks rocker arm system over that of a big block. Even a non race engine will benefit from the "free" horsepower from the friction reduction of a properly designed shaft rocker arm system.

Z.

[Mark O'Neal]

Originally Posted by zrayr

a big block Ford engine will turn over considerably easier by hand than a small block. The difference is the increased friction of the small blocks rocker arm system over that of a big block. Even a non race engine will benefit from the "free" horsepower from the friction reduction of a properly designed shaft rocker arm system.

Z.

So, a roller in a shaft setup, rolls easier than a roller in a stud mount.



Very well, then.

[Frank Messina]

Originally Posted by zrayr

a big block Ford engine will turn over considerably easier by hand than a small block. The difference is the increased friction of the small blocks rocker arm system over that of a big block. Even a non race engine will benefit from the "free" horsepower from the friction reduction of a properly designed shaft rocker arm system.

Z.

I have to disagree. That only holds true if you're speaking about the factory stamped rocker arms. When you move into the high quality stud mounted roller rocker realm all bets are off. The only possible advantage might be high RPM stability under high spring loads but not even that is a slam dunk since a good stud girdle can take care of most any flexing issues. I used to run my drag race motors to over over 8000 RPMs with Crane rockers and a Ridgeway stud girdle with no complaints from the valve train. What will make an engine hard to turn over though is heavy valve spring pressures which is likely what you'll encounter in a high revving race motor vs a more sedate hydraulic cammed boulevard cruiser.
Frank

[zrayr]

Originally Posted by Frank Messina

I have to disagree. That only holds true if you're speaking about the factory stamped rocker arms. When you move into the high quality stud mounted roller rocker realm all bets are off......."

I'm willing to bet a 6 pack of your favorite brew, that with similar valve spring pressures, a 289 or 302 with the spark plugs out & with a flat tappet cam & roller rocker arms will be harder to turn over by hand than a 427 engine with the plugs out & with a similar non-roller camshaft. The difference won't be as much as with a small block with the stamped rocker arms, but the BB will still turn over easier.

Z.