Summit Pro LS "LS3 Variant" Stage 4 cam test in 5.3L
 

We have an interesting report from Richard Holdener on the SUM-8711 cam in a 5.3L truck motor over at Westech. The reason for choosing this cam is it’s the biggest one Summit makes that normally fits with a big intake valve 61cc 5.3 head along with a factory true flat top piston (as used in this engine) without flycutting.

The power gain over a factory LS9 Cam is impressive as it's already great as shown in this test, More impressive is the SUM-8711 made sizable torque gains from the lowest point of the pull (3000)....even being a “stage 4”.

The 5.3L has some Katech ported factory heads on it, but the initial test was done with the early Third Gen Truck intake with 80mm throttle body that probably held the heads back some.

A later article with a different setup but same cam used a $163 turbo as found in this Hot Rod article was done too. While the SUM-8716 Stage 3 turbo cam would have been a better choice perhaps, the Stage 4 LS3 variant didn't disappoint. Still for anyone that regularly reads Richard's articles, the "WRONG CAM" chant is strong with this one lol.

Same engine I believe in both articles. 475 horsepower with the stock gen 3 truck intake and 502 horsepower with the FAST intake. Damn good numbers for an extremely mild 5.3

I've been eyeing the Stage 3 turbo cam for the next engine in my quad turbo corvette, but I was hoping for something on a 111 or 112 LSA with those durations.
I'll be at the Blue Suede Cruise this weekend at Summit Motorsports park helping out one of the guys in the Nostalgia Drag Racing League there.
Maybe before I head back home I'll stop in and look around.

Yes, we spoke to Richard about that and the test wasn't true back to back. He is super meticulous about testing on the same day etc. to rule out variables.

.625 intake lift is pushing close to the limits with factory rockers.

Yes, just below the limit.