[thefloyd1973]

on a sbc 383 stroker with 9.8:1 compression. what kind of compression should i get with the compression tester roughly? the cam is a comp cams part number:12-239-3. the specs are:Operating Range: 1300-5600 RPM
Duration Advertised: 262° Intake / 270° Exhaust
Duration @ .050'' Lift: 218° Intake / 226° Exhaust
Valve Lift w/1.5 Rockers: .462'' Intake / .480'' Exhaust
Lobe Separation Angle: 111°

second. with the leak down tester i set it at 100 psi. than take the rad. cap off and air cleaner. and all the plugs and see where the leaks go right? and what % should i look for?

thanks al.

[carsavvycook]

Your compression should be around 190 give or take about 5 psi.

On a leak down test you will want to have the rockers backed off, and real loose, so that both valves are closed and will not open if the engine turns over from the air pressure. Listen for air in the tail pipe, and crankcase, along with the intake and cooling system. Zero to 20% leakdown is OK depending on whether the engine is new, or not.