i'm putting an edelbrock carb on my nailhead, how many cfm should i get ? my car originally had a rochestser 2 barrell on it. i got a 4 barrel manifold and factory carb for 20$ at a swap meet. will i need a carb spacer or adapter ?
i was going to go with the 600 cfm model 1406 i think the 750 might be overkill. so i am looking for some opinions
make sure you put a metal shield down, then a gasket, then the carb. some people put a gasket, metalshield, gasket. the old rubber type gasket was on my 401, then the metal shield, and the old rubber type gasket again. i don't know what those gaskets were made of, but they were thicker than a normal mr gasket or what ever.
750 is fine for a 401 or 425. Nails love CFM the more the better within reason. D/Q is 1250 CFM. :TU:
What is the code number for your engine? The compression ratio that you have might help in determining what CFM you want. I ran a 750 Carter 9000 series AFB (aftermarket) on my 63 with no problems. The original 4 bbl engines had a 10.25:1 compression ratio. Some of the two barrel engines have a lower comp ratio, 9.0:1. I would think that for the lower ratio, a smaller cfm carb 600-625 would work well. Get the one with the electric choke. I didn't catch the year of your car; the transmissions are different depending on the year of your car. The type of transmission you have will determine what kind of linkage you'll need for your kick down (switch pitch if 65 - 66) Ed
1963 buick lesabre factory 2 barrell. 401 bored 30 over, rebuild about 5000 miles ago or about 7 years ago. new intake of of 4 barrell nailhead not sure year or model. i am unsure which pattern it is because i do not have the intake at my house, its at my garage in wisconsin. i know when rebuild was done they had some trouble getting car to run right, said had to put an extra large accelerator pump in it but i am not sure. i belive the trans is a 2spd dynaflow, which is roasted. but i will be rebuilding soon with the kit from dayco detroit .
Your shift quadrant may have a D and L on it for Drive and Low, but the Dynaflow is not a 2 speed trans. I won't go look it up in my chassis manual unless you insist, but it specifically says that low is to be used only for easing the car out of mud or snow, it's not a driving gear. The dynaflow is a variable ratio transmission that works on the principle of the vanes in the torque converters (plural) changing pitch and decreasing slippage. My 63 Riviera will go from 0 to over 120 without ever shifting gears - smooooooth. For a real cruiser, you can't be a dynaflow. Shifting from L to D at full throttle is not a good idea, the two gear sets are not part of the same setup. One nice thing about a dynaflow, and again I'll quote the chassis manual if you insist, is the ability to push start the car if the battery is dead. Push the car to a speed over 30 mph and pull the shifter into Low. VAARROOOMMMM, and you're off. If the OEM carb you got with the manifold is a Carter AFB (Aluminum Four Barrel) you'll need two gaskets between it and the carburetor. A stainless steel gasket goes against the manifold, and a fiber gasket is sandwiched between the stainless gasket (heat shield) and the carburetor. The exhaust gases that are directed to the base of the carb to warm it for better winter driving, will erode the aluminum base of the carburetor. If, however, you got a Rochester 4GC carb with your manifold, the stainless heat shield isn't necessary because the base of the Rochester is cast iron and the body is pot metal. If it's an AFB, tell me the number - probably four digits and in the 3500 - 4100 range and it could be followed by the letter S - from the base of the carb in front of the bolt hole and I'll tell you the original application. The casting number from the manifold will tell you a date of production. There are some differences due to vacuum demand but nothing a plug won't fix.
thanks for the info on the dynaflow i'm putting an edelbrock carb on it which i belive is aluminum. so i will need heat spacer
I'm at school right now and don't have access to my supplier list, but I'lls send you an email address for a supplier of new thicker heat shields for the AFB. Your dynaflow uses mechanical linkage to control the kickdown so it should be easy to adapt your new Edelbrock to it to make it totally functional.
Taank - Trust me go with the 750 vacuum secondaries PN -1411, and when you buy it get the calibration (jet) kit with it PN-1489. JEGS has the carb for 299.99 and the kit for 49.99 free shipping.
The kit is in case you need to lean-out or richen the carb by changing the metering rods and/or springs, as well as jets. My 750 wass a bit too rich when I used it in a single 4bbl. setup. I will be doing that this weekend. I'll post back with the setup I used, be midful though, I have a D/Q set up now with a 600CFM primary and 750 secondary but I am sure it will be helpful. Just for kicks go to Edelbrock.com, they have a chart and instructions on tuning the carbs.
so today i bought 750 cfm edelbrock carb, and the tear drop shaped air cleaner, accel chrome igniton coil accell plug wires. point and condenser, spent about 500$ after everytrhing, also orderd full gasket set,
I am jumping in late on this thread but, I bought a 750 AFB a few years back and had a bogging problem so I took it to a Dyno Shop and they put the car on a chassis dyno and ended up stagger jetting the carb for a gain of 17 hp to the rear wheels. seems the intake runner lengths difference makes for leaner or richer running conditions. well worth the money. Jim
Jake let us know how she runs after you slap that 750 on. One thing I immidiately did was move the accelerator pump to a lower setting so you get less "squirt" off the line. I'll be re jetting mine on monday - we'll see how I make out as well. :beers2: Jim what jets did you use if you can remeber? o No:
Just my 2cents...return the accel stuff you bought and get ac delco or msd stuff. A stock ac coil works better than an accel...every piece of accel stuff I ever bought turned out to be a P.O.S. ... . 2 sets of wires...one month down the road..open the hood at night with the engine running and it looked like a light show at a rush concert. Their coils break up at 4000 rpm(no, it wasn't the points, I switched back to the 25+ year old stock LEAKING coil and no breaking up till 5800). Alot of flash, nothing behind it(stupid yellow plug wires). They look great but you won't win any races.:rant:
The majority opinion on the YahooNailheadGroup tech site about nailhead distributors is that your first choice would be the drop in MSD, second choice would be to have Dave's Smallbody HEI's rebuild your distributor to HEI status, and third would be to run Crane's electronic ignition to replace the existing points and condenser.
Anthony, it has been too long and too many moves for me to locate. All I remember is it really made the engine come alive. Well worth the money. Jim
