Dcr

I thought I'd throw something out there;

Suppose you wanted to run a Dcr of 8.0, in your 367(40over) iron-headed streeter, so you could run just about any pump-gas. This will get you a cylinder pressure of about 160psi.
I'm gonna try and chart it so you can compare Scr to ICA, and approximate cam size(seat to seat,on the intake) to get it. All numbers are biased to achieve the 8.0Dcr.Keep an eye on the change in cam size as the Dcr rises.
You could run less Dcr, but if you are already buying pistons, what would be the point?
You could try a little more Dcr, depending on your chambers and tuning ability, but another 1/2 point would probably be pushing the limit.
This is just for informational purposes.


.... Scr........ICA req'd........cam*.......LDA ........ICL ...camchange ............notes
..... 8.4 ....... 31 ............ 202 ....... 114 ..... 110 .....zero .............Just try and find one
.... 9.4 ....... 55 ............. 254 ....... 112 ..... 108 .....52*
.. 10.4 ........ 69 ............ 286 ........ 110 ...... 106 ....32*
.. 11.4 ........ 78 ............ 308 ........ 108 ...... 104 ....22*
.. 12.4 ........ 85 ............ 310 ........ 104 ...... 100 ....02*

Now, I know some of you guys are not into Dcr, and that maybe don't see it as being that important. And I agree that if your long block is already assembled and in good shape, there could be a lot of money spent on very little gain.
This chart/exercise is more geared for those whose projects are in the planning stages, and who wish to attempt to optimize it. Sometimes minor changes, can lead to great benefits.
Check out the last two cams! They are basically the same seat-to-seat, yet the 4* tighter LDA, and the re-time allows/requires, a full 1.0point of compression to be come to the target 8.0Dcr!
Also check out the poor 8.4Scr engine. There is almost no way to even get to the target 8.0Dcr!
To be sure there are many other cams that could be thrown into the mix. I just chose popular and makes-sense LDAs and kept it installed to 4*advanced, as common denominators.The actual cams just fall out of the equation.
My last three combos have all been 10.7 to 11.2 SCr with aluminum heads, and the Dcrs have ranged from 8.6 to 9.2. One of them went 93mph in the Eighth at about 3650pounds,at 950elevation,a small cam, and a street set-up; so it made a believer out of me.
As a comparo; my stock 340 Swinger went 98 in the QUARTER back in 1971.Which is about where we all ran. Boy-oh-boy, I thought that car was fast!We all thought 98 was fast.
Have fun.....