MP 292H cam too big?

COMPRESSION RATIO CALCULATOR
Static and Dynamic Compression Ratio

(Considers Cam Timing and Rod Ratio)





ENTER YOUR DATA

CALCULATED DATA



Cylinder Head Volume (cc)

66 (casting #4027596, 66-72.5 cc. 80'-84' 318 HP police sedan head with port/bowl work, 3 angle grind, and stock 360 intake and exhaust valve diameters. Deck milled to true, don't know how much, combustion chamber depth is .105, another unmollested head measured the same). looking for quality singe springs that don't require grinding the seats but support .508 lift (unreasonable?)

Cylinder Head Vol (cubic in.)

4.026



Piston Head Volume (cc)
-1.2 (KB 190-30 with .050 dome)


Piston Head Vol (cubic in.)

-0.073



Gasket Thickness (in.)

0.040 (compressed thickness MP gaskets 4.060 bore)

Swept Volume (cubic in.)

45.665



Gasket Bore (in.)

4.060 (I have MP 10.5:1 max composite gasket with this bore at .040 compressed thickness. Let me know if you think I will need more. Did not want to pony up almost $200 for cometic gaskets).

T.D.C. Volume (cubic in.)

4.484



Cylinder Bore Diameter (in.)

4.030 (360 bored .030 over)

Gasket Volume (cubic in.)

0.518



Deck Clearance (in.)Note: Neg. nubmer above deck, Pos. number below deck

0.001 (using info here based on several abody users' posts about thier build experiences with KB pistons having 1.675 comp ht and un millled 360 block. (How would i figure this while bench racing? Using chrysler block deck height of 9.6", comp ht of piston and crank to deck clearance info from KB @5.999?)

Deck Volume (cubic in.)

0.013



Stroke (in.)

3.58 (Crank has been turned and polished, rotating assembly has been balanced with damper and flex plate (TCI, for externally balanced 360 with 0 balance torque converter). Have matched King main bearings.


STATIC COMPRESSION RATIO


11.184



OPTIONAL DATA



Rod Length (in.)

6.123 (Rods have been resised and fitted with ARP bolts and maching King bearings)

Adjusted Stroke (in.)

2.530



Intake Closing Point (degrees)ABDC @ 0.050 lift plus 15 degrees


74 (Using online Victory library info for MP 292H cam)

DYNAMIC EFFECTIVE COMPRESSION RATIO


8.197


This is KB silvolite CR calculator using all available info and bench racing. If I look at lunati, comp, hughes cams; etc. the intake closing on a similar size cam (duration, LSA, and valve lift) the intake generally closes around 40 ABDC which would give a dynamic CR of 10.302, way too high for pump gas and the street. Recomended pump gas machines should not exceed 8.4 dynamic CR and it is recommended to try to achieve 8.2:1 dynamic CR on high performance streetable machines. I tried to copy and paste but only got some of the info. I filled in the rest. Correct me where I am wrong or offer info please. Dave