89GMCJOHN writes : According to Chevrolet.com they use 1.5 NOT 1.6's in the ramjet .....
Ram Jet 350 Tech Specs
- Part Number: 19355815
- Engine Type: Chevy Small-Block V-8
- Displacement (cu. in.): 350
- Bore x Stroke (in.) : 4.000 x 3.480
- Block: Cast-iron with two-bolt main caps
- Crankshaft (P/N 10243068): Cast-iron
- Connecting Rods (P/N 10108688): Powdered-metal steel
- Pistons (P/N12571703): Hypereutectic aluminum
- Camshaft Type (P/N 14097395): Hydraulic roller
- Camshaft Lift (in.): .431 intake / .451 exhaust
- Camshaft Duration (@.050 in.): 196° intake / 206° exhaust
- Cylinder Heads (P/N 12528913): Vortec iron; 64-cc chambers
- Valve Size (in.): 1.940 intake / 1.500 exhaust
- Compression Ratio: 9.0:1 nominal
- Rocker Arms (P/N 12367346): Aluminum roller style
- Rocker Arm Ratio: 1.5
- Recommended Fuel: Premium Pump
- Ignition Timing: 34° Total @ 4,000
- Maximum Recommended rpm: 5200
- Balanced: External
L31 writes "Here is the Ramjet cammed carbureted 350 dyno test I mentioned before. Looks like GMs rating is actually about 37 hp higher than the engine tested here.
https://www.hotrod.com/articles/how-to-build-a-cheap-small-block-chevy/"
No it actually dynoed with its 98 scrapyard shortblock ,
used cam, shimmed used valve springs ,used rockers and used pushrods and cheap summit non airgap intake 321 hp 4600 399 ft lb 3600 .. so
29 hp and 1 ft lb short which is probably due also partly to the out of the box carb and dist settings they used in this test vs the Chevrolet factory ram injected setup. With carb tuning, a better intake and dist tuning I bet they could have narrowed the gap even more but never equaled the fuel injection. Again basically its a carb setup vs injection .
.
HOT ROD ran the RAMJET crate engine and it scored better than advertised at
Ramjet 413 lb-ft at 4,100 rpm and 364 hp at 5,000.
https://www.hotrod.com/articles/gm-performance-parts-ramjet-350-crate-engine/
My point here is the little 246 duration Ramjet cam does a great job for what it is in the end -
a street torque cam with high vacuum and shouldnt be discounted - again 399 ft lbs and 321 hp at around 9:1
WITH A CARB for a cruiser that does occasional towing imo isnt a slouch compared to the factory L31 ratings at 250HP @ 4600RPM 330FT/LBS @ 2800 RPM which is the starting point and what this thread is about .
...as far as the larger cammed SPO 357 putting out 390-400 hp as you say I think GM marketing would have called it the SPO 360,370,380,390,400 instead if they could get away with it and it was consistently capable of putting down those numbers . 246 256 431 451 109 vs 265 273 473 473 ... Cams arent really in the same class (19 and 17 degree difference)
but surprisingly close in performance IMO PEACE .