Ok I need some help big time... :banghead: i feel like I'm chasing my tail!
To start, this is what I have...1969 383 h code .40 over, Holley 650 cfm, mech secondaries. Mopar heads, Edelbrock performer intake. Melling 23302 cam straight up. Fresh rebuild (although I didn't do it, so there could be ??)
Vacuum is a huge issue or should I say lack of. Off the intake three different gauges read 5 inches with steady needle. Give some throttle up it comes to 17 or so then smoothly back to 5". I obviously suspected vacuum leak. I've tried the propane method nothing, the brake cleaner nothing, the starter fluid (very carefully) nothing and even blocked off the air to the carb and stalled immediately!
I should mention timing, and vacuum advance, the Initial at 11 and all at 38. Vacuum advance unhooked because when the engine gets throttle, revs up but only drops back to about 1100-1200 rpm. Unhook vac line to advance drops right back to idle at 750 rpm.
I thought might be leaking at brake booster if not installed correctly. Bypassed that. Checked vacuum lines to headlights and door actuators all seemed hooked and correct. But getting vacuum right off Edelbrock bypasses all of that anyway.
Where / what else could cause only 5 inches of vacuum? Do I see a rebuild coming up? What do you guys think?
Thank you!! And hopefully you guys can stop the bleeding!!
Myraman:lol::lol2:
To start, this is what I have...1969 383 h code .40 over, Holley 650 cfm, mech secondaries. Mopar heads, Edelbrock performer intake. Melling 23302 cam straight up. Fresh rebuild (although I didn't do it, so there could be ??)
Vacuum is a huge issue or should I say lack of. Off the intake three different gauges read 5 inches with steady needle. Give some throttle up it comes to 17 or so then smoothly back to 5". I obviously suspected vacuum leak. I've tried the propane method nothing, the brake cleaner nothing, the starter fluid (very carefully) nothing and even blocked off the air to the carb and stalled immediately!
I should mention timing, and vacuum advance, the Initial at 11 and all at 38. Vacuum advance unhooked because when the engine gets throttle, revs up but only drops back to about 1100-1200 rpm. Unhook vac line to advance drops right back to idle at 750 rpm.
I thought might be leaking at brake booster if not installed correctly. Bypassed that. Checked vacuum lines to headlights and door actuators all seemed hooked and correct. But getting vacuum right off Edelbrock bypasses all of that anyway.
Where / what else could cause only 5 inches of vacuum? Do I see a rebuild coming up? What do you guys think?
Thank you!! And hopefully you guys can stop the bleeding!!
Myraman:lol::lol2:
