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Paul Ceasrine · 07-10-2010, 11:32 AM

CC'd,
The major difference between the 1969 #LM1 350/255HP engine and the #L48 350/300HP is the compression.
10.25-1 for the 300HP and 9.00-1 for the 255HP.
The 300HP had a 4-bolt main block, and the 255HP had a 2-bolt main.
The Rochester #203 carburetor (750cfm) and #184 spread-bore cast iron intake are the same.
The hydraulic camshafts .390/.410 lift and 258/269 duration, and valve train components are the same.
The cylinder head valves,1.94 intake and 1.50 exhaust valves are the same, but the #L48 350/300HP utilized #041 castings with (63 cc chambers), and the 255HP utilized #441 castings with (76 cc chambers).
Both used flat top pistons with notches.
The #LM1 engine could be ordered in a non-SS car only, the #L48 engine was a SS Package only.
WHEW!!

CC,
Come to think of it, your right. There were alot more guys running the 69' 350/255HP Camaro's with success in 69' thru 73', than the 69' Camaro SS350/300HP.
The 69' SS Camaro's got clobbered in G/S and G/SA (10.00-10.49 wt/hp).
A sneaky class, 69' Camaro 350/255HP convertible automatic in L/SA (70'/71') and/or (SS/NA 1972, National record 12.26; see John Lingenfelter)

07-10-2010, 11:32 AM	#23
Paul Ceasrine VIP Member Join Date: Apr 2009 Posts: 2,546 Likes: 0 Liked 10 Times in 10 Posts	Re: The Best HP Rated Car. CC'd, The major difference between the 1969 #LM1 350/255HP engine and the #L48 350/300HP is the compression. 10.25-1 for the 300HP and 9.00-1 for the 255HP. The 300HP had a 4-bolt main block, and the 255HP had a 2-bolt main. The Rochester #203 carburetor (750cfm) and #184 spread-bore cast iron intake are the same. The hydraulic camshafts .390/.410 lift and 258/269 duration, and valve train components are the same. The cylinder head valves,1.94 intake and 1.50 exhaust valves are the same, but the #L48 350/300HP utilized #041 castings with (63 cc chambers), and the 255HP utilized #441 castings with (76 cc chambers). Both used flat top pistons with notches. The #LM1 engine could be ordered in a non-SS car only, the #L48 engine was a SS Package only. WHEW!! CC, Come to think of it, your right. There were alot more guys running the 69' 350/255HP Camaro's with success in 69' thru 73', than the 69' Camaro SS350/300HP. The 69' SS Camaro's got clobbered in G/S and G/SA (10.00-10.49 wt/hp). A sneaky class, 69' Camaro 350/255HP convertible automatic in L/SA (70'/71') and/or (SS/NA 1972, National record 12.26; see John Lingenfelter) Last edited by Paul Ceasrine; 07-10-2010 at 12:52 PM.