[QUOTE=piecesparts;2361365]
Quote:
Originally Posted by streetstar
You are absolutely right in your assmptions that an engine has to be fed according to the demand. However for everyday street driven vehicles, the overcarburetion of a 750 will (and believe me, I have seen it) cause a slobbering problem at the stoplights. Your top end will be EXCELLENT but your daily drivving will be poor. The Q-Jet has small primaries and then transition to the secondaries which gives the 750 effect on them. Where a Holley, Edelbrock or Carter square bore four barrel has a slightly larger primary when it is a 750 and that is detrimental to daily driving.
This all depends on a couple of other factors 1) weight of the vehicle--a truck is heavier than a Camaro, so it will respond more sluggishly, unless really geared low. 2) the gear ing is the next thing---people of today are trying to get the gearing high enough to keep the RPMs down, that does not work well with a larger bore carb. 3) The 750 will plate out residue on the intake valves as it works in daily driving and cause more sluggish response as time goes on (seen the effects in a machine shop atmosphere.
Holley and Edelbrock corporations; both will tell you to stay at or below a 650 CFM on a 350 motor and even a 383, if it is street driven; to keep the air flow up and the efficiency of the carb working for you, that way the high velocity will make up for the heavier vehicle weight. Granted, my 383 ran hard all the way up to 6000 RPM with the 750, but I could not get the thing to work right on the street--I had to make a decision, so I did not go to the Edelbrock performer carb, which is a 625 CFM carb, but went with the Edelbrock Thunder AVS--which is actually just over 650 CFM---best of both worlds.
The Q-jet is a great choice, if you have a solid one to start with.
|
Ithink you are right on the money peicesparts with your carb knowledge . I have a mildly built 400 with a holly 650 doble pumper. In your opion , is this agood choice. Also having continued problems fouling plugs. Take out & they smell of gas with black sooty tips. Person that built engine thinks by pumping the gas to get it started (no choke ) maybe gas fouling the plugs. Have put new hot plugs in now & keeping an eye on , & not pumping as hard when trying to start . Any feedback would be great .
