sbc 400 ??? @ DCR & CR

[g71rs]

ok some/ most of this over my head...
so if my deck cleans at 9.010" (machines of .015)
68cc heads
-5cc on flat tops
3.75 stroke and 6" rod
4.165 bore

if he uses a cometic gasket thickness are .040, .051, .065
gasket bore 4.200
and the cam above...does the cam have to be degree
can anyone tell me cr...i just want to see if the calculator works right

what would be my dcr...what value should i have.

its more of a street / performance set up, want to be able to run on 93 with no additives

Here is my engine information....any desktop would be great also




sent my information below to comp cams and that is the cam they suggested (below) thumpr retro roller 12-601-8
Cam hydra roller rpm range 2200-5900, advertised duration 291 in 311 ex duration @.050 in 235 ex 249, valve lift .521 in 507 ex, 107 lobe sep

SBC 400, th350 2800 stall, 411 gears, 26 tire
cast Scat Crank internal balance 3.750 stroke 6” Rod Forged Pistons +.040 Scat I-beam 6” Rod 4340 7/16” bolts
Dart Pro 1 alum head 200cc intake 2.02 /1.60 valves 72cc
1.5 crane alum roller rockers
Victor Jr Intake gasket matched...alum
750 double pumper mech sec
Msd Hei Bullet Distributor
Msd 6al BoxElectric
7psi holley fuel pump
1 ¾ headers


I got my dart pro 1 alum heads back today from having the combustion chambers machined...I did the bowl blending and intake runners...
SuperFlow's SF-1020 Flowbench tested at 28.2

my bowl blending and intake runners porting

https://static1.pt-content.com/images/noimg.gif (http://img409.imageshack.us/my.php?image=headflow010zv6.jpg)

blow blending,intake porting, combustion chamber machining
https://static1.pt-content.com/images/noimg.gif (http://img409.imageshack.us/my.php?image=headflow011fr8.jpg)

https://static1.pt-content.com/images/noimg.gif (http://img409.imageshack.us/my.php?image=headflow015ox6.jpg)

how much did it help for hp and torque?
The owner talked me into machining the combustion chambers...He said it would provide more proformance..

My second question is using the above heads and this piston
je piston flat top -5cc 64cc 11.6, 76cc 10.2
heads 68 cc, 4.165 bore with the bock decking never done
what would i have to do to run pump gas 93 octane..
I dont have a lot of piston choices...like to keep cr 10.5 to 10.75


https://static1.pt-content.com/images/pt/2006/08/user_online-1.gif

[Davezz28]

Well since no one answered yet I will chime in.

If you run your first combo with .010 deck and .040 gasket you will have 10.93 static compression. With the listed cam (you did not list the ICL so I used 108) you would have a dynamic CR of 8.11, which would be streetable with alum heads.

IMO there are better cams out there than the one they suggested. My preference for a street motor is to run a little more lobe sepperation, like 110-112 range.

I would also dump the Vic Jr. intake and go with a dual plane like the air-gap or Brodix HVH1016 w/a HVH spacer. For a street performance engine you will have better response and torque down low with a dual plane, they just don't look as kewl as a single plane intake.

[KsKustoms]

He's got it right, DRC should be at about 8:1 for 93 octain street use.