I have a few questions hoping to get answered. I ordered a reman carb from Holley and got what their catalog said was correct for my car- Holley part number 647 306 a q jet which on the body says 7041544 which seems to be a 750 cfm carb for the 350- 1971 skylark my original carb was a 7041540 q jet which was 800 cfm. Holley's rep says that it's fine and that even though the designations of cfm are different that bench testing for all the carbs above are only 680 cfm and regardless of what the outer body says they rebuild it for the specs of each car? 1)My carb has failed and I need to rebuild it- what kit do I use? one of 1540 or 1544- or are these the same? 2)Where do I get the kit and float? Napa doesnt seem to stock these anymore- neither do my usual sources rockauto- or summit racing- TA performance. 3)Should I believe the Holley rep and continue to use the 1544 carb? Oddly the float sank on it after it was less than a year old... Adam
The 350 carb you have is not calibrated for the 455 engine. There is no debate about it. Place an ad under parts wanted for the correct carb and send that one back. It is not correct for your engine. The Holley rep needs to stick with giving advice on Holleys Here is a related issue: http://www.v8buick.com/showthread.php?233288-71-qjet-jet-size-question&highlight=7041544
The Q-jets for 1971 and up big block Buicks are physically bigger in the primaries. For that reason, they are jetted richer. The other difference is in the idle system of the carburetor. A 455 needs more air than a 350. The 455 carburetors have a fixed air idle bypass. That allows extra air to bypass the throttle blades so the engine can idle with a smaller throttle angle. That can be added to a 350 carburetor by someone that knows what they are doing. You can get everything you need from one of 2 places. You need updated parts to resist today's ethanol gasolines. http://quadrajetparts.com/rochester....html?osCsid=dab5948f755775f23d3796b85cb28577 http://www.cliffshighperformance.com/
agreed, and agreed. Should you believe your Holley Rep. No, certainly not on quadrajets. Should you just continue using that quadrajet? You could, if you were ok with the performance and drivability characteristics of the old carb, then it might be ok to use. Heck, you can pretty much throw on any carburetor and it could work, but if you want the best performance, drivability and fuel economy, go with the correct quadrajet for a 455 Buick. JMHO.
you're probably looking for a 7041240 - You could also try Ken at Everyday Performance, he might have one on the shelf....he's listed in the vendor section, and a great guy to do business with...
The 7041544 shares few similiarities with a 7041240, 7041540, or 7041246. It is a smaller cfm casting, with a California emission calibration, using completely different parts and settings that would have been used on a 455 carburetor that same year. It's really not even all that easy to set one of those up for a 455, without intimate knowledge of how they work, correct parts, and what exactly needs to be done for a good end result. I would also add, that Holley "remanufactured" Q-jets are among the very worst I've seen come in here. I hope they send them to a sub-contractor, and are not admitting to doing work of that quality.....FWIW.....Cliff
