340 Static Compression Numbers and Test Procedure

Ignore the dots. You MUST degree a cam to know where it is.

Like I posted above, pull the drivers side valve cover, roll the engine to TDC number 1 cylinder on crossover (overlap) and LOOK at the rocker arms.

If the intake rocker is further open, the cam is advanced. If the exhaust rocker is further open, the cam is retarded. If both rockers are open the same amount, the cam is in straight up.

How far advanced or retarded the cam is can only be known by degreeing the cam.

That piston is a claimed 12.5:1 but you have to be about 64 cc's on the combustion chamber and the piston is out of the bore at least .020 or more, depending on the head gasket thickness.

I'm betting unless the heads have been milled to hell and the block decked a ton, you're probably at a true 10.5-10.8:1 range and that thing should be able to run full timing on 91 pump premium with no issues.

I doubt you'll be able to run a vacuum advance with that, unless you run it off of manifold vacuum and curve the distributor for that.
The real issue is even with manifold vacuum the mechanism works way too slow to pull timing back out and you get tip in rattle.
YR question regarding the compression if using the TRW L2322.

I am wondering if my compression is indeed 10.5-10.8:1. Wouldnt explain the static compression I measured. I verified my static cylinder compression measurements with another gauge type All are "high" `200.

Below I found this info on the TRW pistons (which are indeed .030) If my heads are 64CC (from below table) then si the information below correct indicating ~12.7 CR? Or am I missing something? This does jive with the 200PSI cylinder pressures I am measuring and also why I had seen detonation......... Not saying I have the right CAM as I think its a 4spd grind what every difference that might mean.....

NEW OLD STOCK


FORGED PISTONS

PART NUMBER

224-1836 PERFECT CIRCLE ( SAME AS L2322F TRW)

STANDARD BORE

340 CHRYSLER

DOME PISTON

63CC HEAD-- 13.09 TO 1

65CC HEAD-- 12.68 TO 1

68.4CC HEAD-- 12.05 TO 1

71CC HEAD-- 11.61 TO 1