Agree. This would be the best use of your money. However I did note...
Swapping carbs to go to the track is a PIA. Would you really want to do that to gain what, a couple of mph? If so, OK? But either way if you're going to do any retuning with the current carb, then do it first and check the manifold vac to see if there's really any decent potential in a larger carb.
They have advantages and disadvantages but in principle, the work exact same way.
I just checked that ad out. Unfortunately that's not a good build. If you want to pickup one, get an early one, and preferably one thats not been modified.
Here's a great place to start. Learn to clean to clean 'em and put new gaskets in. There's really no reason why it should have clogged due to a restoration other than portions of fuel turns to varnish over time. The rebuild will cost you time, some gloves (get the black ones), carb cleaner and some gaskets.
Apparently the change in intake and headers and/or the carb overhaul made it run rough (at warm up? on the road? on the track? somewhere anyway - it wasn't the original question, so I didn't create an off-track. but maybe now is the time to ask).
The change from the summit racing intake manifold to the EdleBrock RPM Air Gap changed the performance of the carburetor. The engine has a slight rough running acceleration and is prone to backfiring up the carburetor. It isn't too bad when it's warmed up but it's still subtle in roughness acceleration.. It reminds me of when it running before I had it optimally tuned. It was fine before the changeover. The Airgap is a bit talker and where I had a 1" spacer between the carb and the intake manifold, I could no longer use the spacer due to hood clearance. Since I've had it optimally tuned at one time, I thought I'd go for the 750 rather than spend another $600.00 on a tune.Of course, I realize I probably have to spend that anyways on the 750, if I get a good 10 HP out of it, it may be worth it to me. I'd like to see Mid 12's in my quarter mile run if possible but even if I break 13's I'll be happy. Best time so far, is 13.58
I've had good luck with the electric choke and yes, the current quick fuel double pumper 650 has an electric choke setup. Works good starts up nice and warns up good. I would be more prone to experiment with this carb if I had the 750.i understand the cleaning process, but how are the floats adjusted for optimum performance and how does one determine what jets and metering rods to use? Back in my high school years when it had the AVS 525 Carter I messed around with the carb only to burn up my valves experimenting with the jets/metering rods. I developed severe backfire out the exhaust and it wasn't too long after I had reassembled the engine from a rebuild. I would hate to burn up my current build, so I'm good with leaving carb tunes to the professionals.
Yeah, after the intake was installed, I noticed it was pinging in 5th gear, where it never had before the switchover. I was going to see where the timing marks were lined up but when I put the timing light on it, it was not reading anywhere on the timing mark scale. I knew I had to retard it to get rid of the pinging, so I backed it down very little. Pinging was gone, but it runs slightly rough and has that backfire up the carb especially when cold. Should I try advancing it again. I don't think I must've moved it more than a couple of degrees. It really shouldn't backfire for that , should it?
Ordered my Holly 750 ultra double pumper...we'll see how efficient it is while I experiment in tinkering with my 650....learning how to clean it out and shelving it for a later time to use. Maybe I'll get it tuned at a later date with the car again. Thanks for all your input and suggestions. Might anyone know where I might find a cold air intake for this car rather than sucking the hot engine compartment air? The hood clearance between the carburetor and the inside of the hood is minimal....
My theory of option...
I know a good tune on my current carb would be necessary, but I've opted to try more CFM. We'll see how it performs. Thanks for your offer of tuning and helping out. Although you are a pretty far drive to help me. I'll keep you guys in touch once I take her out to the track this Spring
Sure, why not?
So why go back to what you know is no good? Keep going 'til its better (or gets worse in some way). Signs of too little advance will be that it acts sluggish and runs hot.
Too many unknowns. Was this done with vacuum advance? Plug the vac advance for base timing measurement. When done, if the base timing was anywhere from 12 to 20 BTDC, make sure the the vac advance hose is attached to the timing port on the side front metering block.
