427Swede
Well-known member
The 427 is running nice and strong, up until 5500rpm where it starts to misfire. Or maybe not misfire, it is more like it is running out of breath.
The Rochester carbuerator is functioning absolutely flawless below 5500rpm without any hesitation or tendencies to bog. It is totally renovated to factory 427/390hp specification with the exception that it has been compensated for todays low quality fuels with alcohol in them.
I'm thinking that my engine probably needs more fuel at higher rpm:s. The carb was built before I decided to upgrade the engine with a comp XE 268H cam and I probably should have done something about the carb.
A friend of mine drove the car yesterday with me sitting at the passenger seat and thats the first time I could actually feel the engine starting to pull like crazy at 5000rpm untill it slows down after 5500...
I have a Carter mec. fuel pump so that should not be the problem or? Could the very heavy pump shaft begin to develop a "float" condition at higher rpms?
Engine: 427 0,030 over, 9,5:1measured comp. Original, restored oval port heads. 268H Comp cam with matching comp springs and lifters. Comp roller rockers. Original alu intake. MSD pro billet dist and 6al 2 box set to 6500rpm. (A bit too high...)
The Rochester carbuerator is functioning absolutely flawless below 5500rpm without any hesitation or tendencies to bog. It is totally renovated to factory 427/390hp specification with the exception that it has been compensated for todays low quality fuels with alcohol in them.
I'm thinking that my engine probably needs more fuel at higher rpm:s. The carb was built before I decided to upgrade the engine with a comp XE 268H cam and I probably should have done something about the carb.
A friend of mine drove the car yesterday with me sitting at the passenger seat and thats the first time I could actually feel the engine starting to pull like crazy at 5000rpm untill it slows down after 5500...
I have a Carter mec. fuel pump so that should not be the problem or? Could the very heavy pump shaft begin to develop a "float" condition at higher rpms?
Engine: 427 0,030 over, 9,5:1measured comp. Original, restored oval port heads. 268H Comp cam with matching comp springs and lifters. Comp roller rockers. Original alu intake. MSD pro billet dist and 6al 2 box set to 6500rpm. (A bit too high...)