TBART1970 wrote:WBR33 wrote:I didn't see it posted anywhere, so I'll ask?
What heads are these? Edelbrock? Which model, what valve size? Looks like they may have had some chamber porting/polishing? Any other work to them?
What model spark plug are you running in them?
Edelbrock Performer RPM. 2.250 Intake. Chambers pushed. Bowl work.
NGK BPRE11 I think.
IMG_20170325_204841.jpg
Thanks for posting the cylinder head info up.
Engine made 690HP/750TQ. With heads that flow
With heads that flow 323cfm peak and approximately 313cfm at .650 lift,
which is the cam lift the op is using.
A couple of things here, first I am surprised that these heads do not have higher flow numbers
for the valve size and given they are a bbc head. This puts us at 2.2HP per cfm which is on the strong side, I would think air speed has to be getting up their as well.
Cam #2 (new cam) is closing the intake valve 7.5* later.
The cam is longer duration by 5 degrees (intake) and has a wider lobe separation by 2*
I would like to see the new cam on a 108lsa installed straight up not 2* early which
would keep the intake close at 51.5 atdc and add some overlap which I think will help this deal.
Seems to me like this big engine is somewhat starving for air, and is going to be done at 5600.
Thoughts?