Quote Originally Posted by 1project2many View Post
Does anyone know how GM populated this table? It seems like the L30 and L31 tables should have some type of relationship that's easy to see. Base engine friction seems like it's going to be affected by stroke and bore more than anything else. The L30 and L31 are very similar, with the only major difference being the bore and possibly a slightly smaller cam on the L30. Yet comparing this table between the two engines shows some unexpected differences. Has anyone played with this or maybe heard something about how the tables were developed? Any theories???
L30 and L31 use teh same 191/196º .412".428" 111ºLSA cam. Same cam used in the 1994-96 Impala SS/Caprice/Roadmaster/Cadillac GEN 2 5.7's with iron heads as well as the 94-96 GEN 2 4.3 V8(VEE eight) Caprice engine(200hp). That cam was pretty popular.

Between the L30 and L31, I'd think the L31 would have slightly more friction due to the greater ring/bore contact vs. the smaller bore L30, but who knows.

So I looked it up, here you go.

Vortec 350 L31
0-400-800-1200-1600-2000-2400-2800-3200-3600-4000-4400-4800-5200-5600 rpm
14.00 17.00 20.30 23.70 26.59 31.00 38.41 45.91 54.00 61.30 68.59 75.09 82.00 89.00 96.00 0kpa
17.16 20.92 25.09 28.09 29.92 34.08 41.31 49.89 57.72 62.27 69.67 75.05 80.61 87.59 94.55 20kpa
19.83 24.77 30.52 33.13 33.44 36.64 43.61 52.70 61.23 63.66 70.48 75.20 79.92 84.77 91.64 40kpa
23.33 30.36 34.78 37.27 36.86 39.05 45.56 55.08 62.70 65.13 70.78 74.09 77.83 81.94 87.27 60kpa
26.83 32.67 39.13 41.44 40.19 41.19 47.03 55.91 61.98 64.39 69.31 71.16 75.05 79.11 84.36 80kpa
29.17 35.63 42.25 43.91 41.80 41.69 47.31 55.16 61.39 63.08 65.44 69.50 73.66 77.70 82.91100kpa

Vortec 305 L30
15.92 16.92 18.11 21.36 26.09 30.70 35.25 40.69 47.50 55.28 62.39 69.86 77.03 84.00 91.00
19.77 20.77 22.13 25.00 29.42 33.78 38.09 42.53 48.73 56.27 63.20 69.56 76.94 83.80 90.41
23.39 24.39 25.86 28.72 32.75 36.70 41.50 44.94 49.95 57.23 64.16 69.73 77.42 83.00 89.50
27.47 28.47 29.53 31.98 35.88 39.34 44.44 47.47 51.31 58.08 65.42 69.55 76.52 80.00 87.00
30.63 31.63 32.91 34.97 38.56 41.52 46.09 49.17 51.70 58.28 64.25 68.75 72.70 77.00 82.00
33.59 34.59 35.91 37.70 41.09 43.50 47.59 50.70 52.09 58.41 63.80 68.00 70.00 73.00 76.00

Vortec 454 L29
22.39 27.09 31.88 34.67 40.72 48.83 59.95 75.03 90.53 104.47 114.80 121.06 125.23 131.30 136.55
27.98 31.44 35.17 37.11 43.08 50.36 60.77 75.53 89.91 104.05 114.48 120.72 124.75 130.83 135.16
39.19 42.92 44.77 43.95 49.23 55.50 63.86 77.08 89.91 103.20 113.75 119.70 123.77 128.45 131.91
48.14 49.86 51.16 50.30 56.42 61.67 67.98 79.14 89.91 102.16 112.19 117.97 121.33 124.64 127.27
54.86 55.92 56.48 55.09 64.63 68.88 72.09 81.70 89.81 99.42 107.92 112.89 114.48 118.94 120.77
52.63 53.11 54.36 50.80 54.36 60.64 74.16 79.14 87.33 93.11 99.14 102.72 106.66 107.52 111.47

peace
PAuly