6901 specs;
276/288/114;lift of .441/.441; .050 of 218/228
Summit recommends; a 9/1 Scr, a 2000 stall, and "higher" gearing.
As you can see, the ramps appear to be extremely long, but they don't tell you at what lift the advertised was measured at.
Typically the advertised durations, from most manufacturers are either .008 or .006 tappet lift.
If that was to be the case here, then the ramps from advertised would be 58*/intake, and 60* on the exhaust. Other more popular cams are 44 to maybe 48 degrees. So you know these Summit ramps are a lil on the slow side. By itself this is usually not a bad thing. The cam should last a long time.
However, the cam is on a 114*LSA, so the big picture, installed at 110* is this;
276/288/114/
Ica of 68*
112*of compression/98*of power extraction/54*overlap
and so
In a 9/1Scr 318(+.020),at 800 ft elevation, the Dcr comes to 6.96@132psi, and an extremely low V/P of 95.
read about VP here
V/P Index Calculation
But at 8/1Scr; the numbers are; 6.22Dcr/113psi/81VP
The 228 cam @.050 makes peak power at about 4800, but the peak is long and flat so hard to find..
What the numbers mean;
First off, the 318 at these low VPs, will be a slug at low rpm, the 2000 stall that Summit says will work, will make your 318 feel like a 225 on the start line.
The very low Dcr of 6.22, in an 8/1 318, means you can probably burn the poorest gas imaginable, without detonation.
The 54* of overlap may make it idle with a bit of lope.
At 112* of compression and just 113psi, this engine will be a big disappointment with a 2000 stall, and hiway gearing.
At just 98* of power extraction, she has no-chance at ever making fuel economy, until the rpm is quite high.
But the biggest deal is the 12* difference, in intake to exhaust duration, which IMO makes this a Thumpr-type of cam; unfortunately, not a very good one.
Typically, a 218* intake duration will be found on a 262 advertized cam.... not a 276 like the 6901. At 8/1Scr, this cam will be very soft to at least 3000rpm, then a lil less soft to around 3800.
But it should be easy on the valve-gear. Hooray.
Now recall what I said at the beginning, namely; "As you can see, the ramps appear to be extremely long, but they don't tell you at what lift the advertised was measured at". So if NOT at .006 to .008 tappet rise, then the picture could be worse or more likely,slightly better, but the 12* split is still about double of more typical cams.
Here are my opinions;
A low compression 318 cannot afford such a late ICA as 68*, nor long ramps. While the 218* of intake duration is a pretty good size for a 318, there are many other cams better suited to a 318 than the 6901.
Or if you want to run that 6901, your 318 needs to have the Scr pumped way up; Ima thinking 10.5Scr/161psi/ Vp of 116 which is still crap, just not as crappy as 81
