318>390 Stroker.......Your thoughts

Dave81 said

318 (76) taken out to 390:
Scat cast crank and rods.
ARP everything on the bolts.
Diamond forged pistons (16.7cc).
Eddy RPM 60779 Cylinder heads (standard) c/w felpro 1008 head gaskets.
Hughes Cam - Solid flat tappet - HUG STL4246AS-8 Hughes Engines
I've calculated 9.9:1 SCR at 0 deck Low 8's DCR

Click to expand...

HUG STL4246AS-8
SB SLD FLAT TAPPET CAM 242/246 -108ºLSA
.376"/.389" LOBE LIFT
That's a pretty big cam. With alloy heads, it will want a lot of Scr. I wonder if you are using the DCR calculator properly. It needs the advertised numbers, NOT the .050s. Yur gonna need a lot more than 9.9 to get to low 8s Dcr. Alloy heads will easily support 185psi on pumpgas. I have run that on 87E10
Your swept is 799.18cc
Your total chamber at zero-deck is about 63+8.6+16.7=88.3
Your Scr is thus (799.18 +88.3)/88.3= I get 10.05.

But Hughes does not publish the advertised, which is a pita.
so you have to either guess or call them.

If I guess , I will get 288/292/108 and in at +4 I get an Ica of 68*
Now because that cam is a solid, your Ica might change after lashing to say 65* and
Wiki says you are at 236ft elevation.
Plugging those numbers into the Wallace calculator, I get a Dcr of 8.0 @163psi.. That is fine for Iron heads and pumpgas, but with alloys, that is leaving a lot of performance on the table, especially low-rpm torque.
To get to 185psi, will require a change in Scr to ~11/1..
So, I would call Hughes