harascho

Hi folks,

I am thinking about some carb upgrade for my 1966 Toronado. Despite all actions my old carb is still leaking from the fuel bowl into the manifold. After just one day sitting it needs serious cranking to restart.
I repaired the well plugs with threaded plugs and glued them in. They withstood the soap and pressurized air test, but there was no change from the very beginning.
I am tending towards the complete aluminium casting beeing the cause of the trouble. Over the years it might become porous..

To give me something to work with I am looking for the latest electric choke Quadrajet comming of a 455 V8 to start with.
In which years of a 455 Toronado could I find something suitable? The younger the better...

Here's a more brief summary of the current situ:

The engine was overhauled, bored, mild cam, roller rockers added, still flat tappet lifters.
The pistons are + 0.040“ from Racetec and the engine now is a 434 cui instead the original 425 cui. Compression is around 9,7 :1

I overhauled the carb after a lot of research as I guessed my experience would be ok.
I cleaned, straightened the body, bushed the shafts, installed new Cam, a gasket kit, removed the idle tubes, cleaned everything and installed new ones, drilled out the well plugs, threaded the body, built threaded plugs and glued them in place….

This is what I’ve got now:

Problem 1 „Starting after sitting a while“:
Once started and driven it starts after the first turn oft he key. Sitting a day or two you have to crank it a lot until it will start. Sounds to me the carb is still leaking fuel although the well plugs were addressed. I installed a glass bowl fuel filter to see if that empties in that time.. -> NO. It stays at the same level and with the turn of the key the new fuel pump immediatly pumps fresh fuel through the filter.

Problem 2 „ Performance“
I would have expected a little more uuuumph from that new setup. I’m not able to „smoke the tires“, it still doesn’t feel like a almost 400 hp car.
It has good VAC, a nice rumbling idle, there are no VAC leaks around the carb, from the plugs color it runs a little lean. What I see at the carb that the top gasket always is a little wet with fuel.
The secondarys open, the throttle blades open to a full 90 deg.


cheers

Harald

joe_padavano

Before jumping into a carb change, are you SURE the problem is a leak. Yes, your 66 Qjet is one of the early ones prone to leaking bowl plugs, but you've fixed that and it wasn't the problem. How about verifying that you really DO have a leak before condemning the carb? Simply remove the carb from the engine, prop it up over a piece of paper, fill the float bowl, and let it sit overnight. If the paper isn't wet in the morning, there is no leak and your problem is elsewhere.

TripDeuces

It's probably leaking internally from the little tower in the bowl next to the needle and seat. It will have a brass plug in the top.
Mine leaked so bad it poured fuel out of the bowl. I fixed mine with an aluminum plug and JB Weld but I'm concerned the JB Weld may not stand up to gasoline over an extended period. Not sure really.

joe_padavano

Still a very easy thing to test BEFORE spending $300 and hours fixing collateral damage to install a different carb.

shiftbyear

Harald,


The carb you are using is a 71 chevy unit according to the number. An original 66 Toro might be expensive. I would suggest the later 77-80 Chevrolet qjets. Better castings and electric choke. I can't imagine what is leaking but Joe gave a good suggestion. As a last resort I'd call Cliff Ruggles.

shiftbyear

Oh, by the way, nice plant. 66 Toronado's shred, they are my favorite year. Good luck