This is the problem. I have a 427 Big Block Chevy Rat motor but i have no low end. The truck feels as if its pulling 10,000 pounds below 3,000 rpm's. The motor is a three month old rebuild with 049 casting heads, full roller rockers, performer intake, headers, Edelbrock perormer cam, Holley 750, 9.5 compression, MSD Off road system, ect. The engine is built for low end but feels dead below 3,000 and then dies off at 4,500-5,000. I have 2%-7% leak down in all cylinders so they are sealing up great. But my cranking compression is low at about 125-127 psi. This I thought was due to incorreect valve timming but i checked and it was correct. No I didn't degree the cam in. Its a truck motor and someone stole my degree wheel, plus the timming chain is a 60.00 comp cams unit, it should be correct. I just replaced the cam with comp cams Extreme Energy 262H. They sugested it and my computer dyno gave the engine 60 more FT at 2,000. 218/224, .504/.510 lift. 110 lob seperation. The old cam looked great and specked out good after removal. The lifters all looked good. With the new cam I see a little more low end but still my old 350 had the same but then again that didn't have enough. I made an attemp at power braking the truck and the engine will not break the tires loose. The engine pulls the converter to about 1,800 and then the engine will not rev any higher the tires don't break loose and then the engine will missfire as it loads up. Every thing checks out good. The engine runs great it dosen't missfire or skip, plugs are clean. I have tunned and changed carbs and ignition systems with no change. I thought a valve problem but my leak down is good my cranking pressure is still low with both cams. The 350 would do the same thing when powerbraking that. I thought the converter a few years back but when the tranny went I replaced the tranny and converter with a set from my other truck and it still did it. Its driving me crazy i can build a 10 secound car but my truck won't get up and go. Even with the problem it rund 15.84 in th 1/4 but 0-60 9 secound times, it comes on hard after the lugging on the bottom end. The cam is ment for idle to 4,500 and thats about the redline. What do you think.