Thanks Matt - I took Tom's suggestion and bought two brand new floats for the other carb. They havent come in yet, so I've been concentrating on this carb. The carb that needs the floats is my cruising carb, this one is my 1/4 mile carb - I built two so I can leave one in "known good" mode, and screw around with the other, jetting, rods etc..and see how it affects my ET. With this carb for instance, I went up one size on the secondary jets to .086, and put in rods with a .047 power step. I have no idea if thats made the car any faster, but it seemed to make sense after increasing plenum volume with the "doc mod", and it does run pretty good when it's not flooding out. Hopefully I'll be able to get in a couple of runs before the end of the season and see if the jetting/rods have made any difference.
Naw, just get an adapter plate, buy a Holley 750 dbl. pumper. Port match the adapter to the manifold & to the throttle blades of the carb. & you WILL notice a difference. You DON'T want 50cc accelerator pumps, only 35cc's. Some re-jetting will be needed as right out of the box it will be TOO rich. I've had the 750 Holley dbl. pumper on my '64 Riv. for 35+ years now & 2 re-builds. I even made my own auto choke using old parts from older Holley carbs. At the ROA Nats in Hershey, Pa. this past June many were amazed at how I was able to start it after sitting all night & just leave the parking spot with no warming up, stalling,hesitation or otherwise. Same after it was warmed up. All I had to do was turn the key from outside the car & it immediately started. I had to open my hood for all to see that it WASN'T fuel injected. Many were amazed!!!!
I'll have to come down one of these days and check out your set up...This would be a perfect weekend for it, but the car is in the transmission shop...the ST-300 is now slipping under hard accelleration, which is another story for another day....
STAY WITH HIM, TOM,,,,,, SICKEM BUDDY.....:laugh: :laugh: I told him he needed a holley.....:Brow: :Brow:
Would a Q-jet pancake air cleaner fit over the Holley? Honestly, if I could keep it OEM looking I'd consider it.
Rhett,,,, pard,,,, a qjet base will fit,,, if you grind off the 2 little tabs that locate it on the carb.... that is what I used for my air cleaner that I just built,,, a qjet inner flange .... but my original air cleaner was for a carter... and too small for a holley.... but if you already have a qjet air cleaner,,, just grind those tabs off and it will fit right on a holley.....just measure the diameter of the two.... before you do anything...
Yes, it will Rhett. If I remember correctly the adjustable float area needs to be "bumped" up a little to clear. It's underneath & not noticeable.
This might work for you.... I put some later AFB's on my 2x4 intake, they have a larger opening than the originals. I made a spacer about 3/4" high out of a big coffee can. Spacer fits the larger OD of the carbs, and the stock 2x4 air cleaner fits on top of the spacers. It ain't perfect since there's a slightly smaller opening over the carb, but you can use the original air cleaner, so that's a worthwhile benefit. BTW, the later AFB's are shorter than the early originals, so height doesn't change much with the spacer. Hey Tom/Doc, I have a 750-ish Holley vac secondary carb here....how does that compare to the dbl pumper or 3 bbl?
What I like most about dbl. pumpers is the instantaneous response when you put the pedal to the medal. Also, as you tune the secondaries to open when you want, usually sooner, now the spring is lighter. When your foot is to the metal & the secondaries are at WOT, when you release the pedal there is a split second where the secondaries are still open & the engine is still accelerating. DON'T LIKE THAT FEELING!!!! Even the old Ford 4bbls. do the same thing. When I take my foot out of it I want it to start decelerating, NOW!!!!!!
An update - After swapping needles, seats and floats in the current AFB and never solving the flooding issues, I took Tom's advice and bought two NEW floats, and put them in my other "last known good" carb. Now it runs great, makes good vacuum and doesnt leak anymore. Just for fun, I took a set of richer metering rods I got from Carmen and dropped them in... Ran my best ET ever - 14.69 @ 98.3 (as measured by G-Tech meter) Surprisingly, running heavy (full fuel and toolbox) helped great with the launch and 0-60 (6.1), but didn't hurt the overall run. Might have to rethink my philosophy a little. Thanks to all for your input
Next up is a driveshaft loop and control arm braces- it's time. Then a Switch Pitch controller- cant decide to rig something up myself, or go the fully automated route with one of Bruce Roe's controllers - spendy, but pretty trick. The the rear axle - it's an open 3.08 now, and I've got a set of 3.23s. I've gotta figure out if I want to step up to the next size carrier and go with 3.36s or 3.55s.I still drive this car on the highway, and 3.55s will put it close to 3500 rpm at 70, while the 3.08s are around 2900. Limited slip is a given, traction seems to be my biggest issue now.
Yeah, guy, you need to do the rear gears next.... that will add to the go power a tremendous amount....other than the engine swap , the diff swap did more for my original car than any other thing.....
You can test what the car would feel like with different gears by putting on a pair of short tires on.....I wonder what a pair of mini-spares would compute out to. What size tires are you running now?
Running 225 14s - As an aside, can anyone tell me how wide the rear on my 65 Gran Sport is? From where are those measurements usually taken? The axle flange? I've got a line on a free 8.5 rear, I'm going to take a look at it tonight. Although my rear has been fine, I understand they arent the strongest. I wouldnt mind building a 8.5 and swapping it in, and leaving mine box stock on the garage floor. Thanks,
Just reading up on an 8.5 swap, might not be as cut and dry as I hoped.. Apparently there's pinion angle and length issues....
Rhett, I recently installed an 8.5" out of a '68-'72 Olds Cutlass (12 bolt cover) into a '65 GTO conv. The rear was about 1 3/4" wider. Since it was a 4spd. Muncie there were no changes to the driveshaft nor the pinion angle. Even the original Rallye II wheels fit without having to do ANYTHING to the wheel wells or WOM.
