Timing ?

[metcoll]

440 with six pack pistons rpm heads that flow around 300@600, lunati hydraulic 240/250@050 520/547 rpm intake 850 carb..where would you guys put timing at..heads were not milled, what approx compression ratio would I have(closed chamber heads

[c00nhunterjoe]

What heads, what head gasket, what part number pistons.

[metcoll]

2355 pistons, rpm 84cc closed chamber heads  & 039 gasket

[firefighter3931]

Depending how far the pistons are below deck.....that combo would yield between 10:1 and 10.5:1 and should run fine on pump gas. 

With that cam I'd be setting the base timing at 24-25* BTDC and limiting the mechanical advance to 10* for a total of 34-35* with a fairly quick curve....all-in by 2400-2500 max. 


Ron

[myk]

Every engine is different, so you have to time it by ear as well as trial and error before you find the right setting.  There is no generalized number...

[Kern Dog]

I ran a similar combo and calculated my CR at 9.7 to 1. This was in 2004.