quote:Originally posted by Aus Ford:
I've seen lots of stock 351c's with 750 carbs and they have worked fine.
It is a vac secondary, so even if the throttle is stood on the engine is only going to see half the carb until the airflow goes up.
1/2 of 750 is only 375 cfm. That should not cause the off idle bog that has been described.
Though if i was going out to buy a carb for a stock motor i agree a 600 is what i'd go for.
Sure. I used a 4779, 750 dp for quite a while BUT the engine could use it, the car needs to be geared for it and I have obviously a different definition of "stumble".
A 600 is definitely going to be "crisper" and the 750 definitely "lazier".
There is no telling what people "expect" the engines reaction to be?
I have run the Shelby 715cfm, Ford "Boss 302" carb and the 428cj 735 carbs on a 12.0:1 cr engine with 3.70 gears and 2.32 1st gear top loader.
They were all slugs.
The 600cfm vacuum secondary R-1850 was by far the most "responsive". That IS the carb you want for your lowest 0-60 times.
The 4779 worked best on the Edelbrock torker but the combination was very "flat" until about 4,200 rpm.
Again, what "stumble" means to one person is not what it may mean to another?
The carb in question here MAY in fact be acting/reacting exactly as it should and the driver not expecting this type of a reaction?
This is very difficult to decipher from afar?