by RodStRace Tue Apr 20, 2010 4:45 pmdestro360, Didn't mean to imply you were wet behind the ears. Your posts show a good knowledge, so I'm sorry if I offended.
Sounds like you have covered all the bases, so either you missed something (doubtful) or it's a problem beyond normal repairs (common on older stuff).
The following are suggestions based on the info you have provided and what I have run across, not indictments of your work.
1. Coil weak. Commonly fails open (no spark) or shorts across the windings (less power). Full throttle is the time when the most spark is needed, so if it's marginal, it could cause this. A 'scope is the best tool to check this. Hooking up the coil backwards can cause issues, but it's normally a high speed miss, not a load problem.
2. Spark scatter. I have never seen this on a Mopar, but have on other brands. Due to the Dist. being off (phasing), the rotor is not pointing at the cap terminal, but in between 2 terminals. This can cause the spark to jump to the further terminal under high load since electricity follows the path of least resistance.
3. Engine issues. Weak rings can also give up the ghost under high load. Usually is followed by lots of smoke which you have not mentioned.
4. Obstruction of exhaust or intake. The exhaust usually hits at higher speeds, your description is at any speed under high load. That's why I suggested a vacuum gauge. Intake clogging also tends follows this, but is more load sensitive.
5. Power circuit in the carb. I've seen a few carbs that will fall flat when opened past a certain point. Quickest test is to squirt carb cleaner down the throat of the carb when it bogs. This can cause a big flaming backfire out of the carb, so be careful!
Sounds like you have covered all the bases, so either you missed something (doubtful) or it's a problem beyond normal repairs (common on older stuff).
The following are suggestions based on the info you have provided and what I have run across, not indictments of your work.
1. Coil weak. Commonly fails open (no spark) or shorts across the windings (less power). Full throttle is the time when the most spark is needed, so if it's marginal, it could cause this. A 'scope is the best tool to check this. Hooking up the coil backwards can cause issues, but it's normally a high speed miss, not a load problem.
2. Spark scatter. I have never seen this on a Mopar, but have on other brands. Due to the Dist. being off (phasing), the rotor is not pointing at the cap terminal, but in between 2 terminals. This can cause the spark to jump to the further terminal under high load since electricity follows the path of least resistance.
3. Engine issues. Weak rings can also give up the ghost under high load. Usually is followed by lots of smoke which you have not mentioned.
4. Obstruction of exhaust or intake. The exhaust usually hits at higher speeds, your description is at any speed under high load. That's why I suggested a vacuum gauge. Intake clogging also tends follows this, but is more load sensitive.
5. Power circuit in the carb. I've seen a few carbs that will fall flat when opened past a certain point. Quickest test is to squirt carb cleaner down the throat of the carb when it bogs. This can cause a big flaming backfire out of the carb, so be careful!
the thing that bugs me right now is i have a brand new webber 32/36 off my old datsun that i would really like to try out on my van but as far as i know i'd have to find a special intake to do so.... im leaning towards defect carb or dist problem.... i just dont know at this point.