340 cam timing, 1.6 rockers?

[RustyRatRod]

So exactly how do you change cam timing on a 318 or 340? Just advance the gear a tooth?

No. That would be way too much either way. You can advance or retard camshaft timing with the offset camshaft woodruff keys or a crank sprocket with multiple keyways, or both. Of course to know "where you are", you certainly need a degree wheel.

 

[AJ/FormS]

Pistons are cast, they come up 0.1045” shy of the deck. They have 4 valve reliefs cut in the flat top.

The only things that are saving your combo is the clutch, and the low-lift cam, which points to a short period.
With flat-top pistons down .105 inch, in 4.07 holes, that is 22cc, add the rest up and you might be looking at 105cc total, making your 340, a 7.73 Scr 345 cuber.
TM (Torque Multiplication) is the great equalizer; what rear gears are you running?

Like Wyrmrider said; put some compression test results on the table.

1.6 rockers at this level, is a waste of money.

 

['63GT]

So exactly how do you change cam timing on a 318 or 340? Just advance the gear a tooth?

NO. a tooth is like 20°. You'll need an offset key like below. (IF you need 2°)
Mr. Gasket Crankshaft Keys 987G

 

[Terry Will]

No. That would be way too much either way. You can advance or retard camshaft timing with the offset camshaft woodruff keys or a crank sprocket with multiple keyways, or both. Of course to know "where you are", you certainly need a degree wheel.

Thanks, Much!

 

[AJ/FormS]

I did that once, in my teenage years. I installed a seriously used 340dual row on a 318, complete with the used sprockets. Advanced one sprocket tooth. Buttoned her up and ran her for years like that.

 

[furrystump]

If your plan is to continue to chase power and you need new rockers, you can grow into the 1.6’s. But like stated before, you are really getting close to an all out effort when you start “needing” a 1.6 rocker. Increase in total lift is not the primary benefit, snapping the valve open faster to a usable lift number is. At that level there won’t be many parts remaining on the motor that are there now.

 

[Krooser]

Old school cams had tons of duration but not much lift. The heads back then could not support more lift anyway.