.................Return to Sumner's Home Page ........................ Return to Tech Info Index

..............- DCR Combinations That Have Worked -

........................................................--- For Big Blocks ---


The purpose of these pages is to helpfully show what DCR (Dynamic Compression Ratios) and SCR (Static Compression Ratios) have worked with what Octane gas.

You have to realize that there is more to this than just the DCR. Other things that will effect the octane you can run are altitude, load, quench, timing, combustion chamber shape, piston top shape, etc.. So use the following as a guide for what has worked for others and go from there.

If you know your combination and would like to share it please e-mail me your information (see this page for e-mail address). Use the examples below to compile your data. The more we have the better it will be.

Note: Here is a link to a DCR & SCR Calculator. Please try and use this calculator so we are comparing apples to apples. If you use a different one please let me know. Also if you can fill in all of the fields then we can double check each others calculations.

...........................(I'll try and keep these in order of lowest DCR to highest DCR)

(Note: I'm not very familiar with big blocks, so help me out with the bore/stroke/rod length of your combinations.)


cruzn65impala -- Troy (on http://www.chevytalk.org/): Runs fine on 91, but really wakes up if I add 5 gal of F&L 111 octane then top off with 91 octane.

DCR = 8.11 SCR = 10.26 Octane = 91    
Heads early closed chamber oval ports (casting 206)  99 cc Chambers

Polished
  Lobe Separation 110  Lobe Centerline 106 
Cam Comp 280 Magnum hyd 
230/230
@ .050
Lift =.520/.520

1.7 rockers
Advertised Duration
Pistons  TRW L2240NF pistons     21cc dome
402 cu. inches Bore 4.124"

bored .030
Stroke 3.76

(396/427)
Rods 6.135 Headers
Piston to Deck Head Gasket
.041 thick,

4.540 bore
Initial Timing
16*
Total Timing
34*
Induction
650 dbl pumper (Proform main body - 780cfm?)
RPM intake


Put your combination here...................

DCR = SCR = Octane =    
Heads   cc Chambers   Lobe Separation  Lobe Centerline 
Cam  

@ .050
Lift = Advertised Duration
Pistons       cc
355 cu. inches Bore 4.030 Stroke 3.48 Rods 5.7 inch Headers
Piston to Deck Head Gasket Initial Timing Total Timing Induction


............Return to Sumner's Home Page ........................ Return to Tech Info Index