The Stovebolt Site Forums The Shop Area Engine Shop Need advice to get this 261 running right

I am finishing up the swap to a 261 in my 1950 Chevy Sport Coupe. I have it running, but not well. I need any advice you can offer to help me get this engine running well.

The 261 is out of 1961 Truck. I has a dual Offy intake with two Carter W-1 carbs that are freshly rebuilt. The carbs have been synched using a Uni-synch tool. Exhaust is flowing through a set of Fenton headers and Smitty's glass packs. Ignition is a stock distributor with a Pertronix ignitor kit and coil. All plugs and wires are brand new. New radiator and water pump. Stock fuel pump.


Heres the issues:

The engine is a little tough to start. Takes alot of cranking to finally turn over. After that it seems to run pretty well while parked. The real issues come when I begin to drive. The car seems real sluggish when given gas in gear. The acceleration is real gradual, without any real power. If I give a good stab of the gas pedal it feels like it bogs down, almost dying out. The exhaust has some popping during acceleration but I am not sure if it is just normal exhaust notes playing through the glasspacks. The engine runs nicely if I give it a nice slow, drawn out acceleration. With this approach, there are no noticable problems.

I messed around with the carbs a bit today to see if things improved. The W-1's only have two adjustment screws. The first is idle speed and the other is the fuel misture. After minor tuning I did not really see any improvement in driving performance.

I then tried adjusting the timing. The timing light that I have didn't seem to be getting a good enough signal through the #1 plug wire. The light flash was very inconsistant. The clamp that goes around the #1 wire seems too big and doesn't make very good contact on the skinny plug wires. I made some minor adjustments to the timimg in both directions (advance and retard). I saw some improvement when I advanced the timing a bit, but the engine started running real hot, nearly overheating.

The next thing on the to-do list is to adjust the valves. I hope to get some time this weekend to get that done.

This is my first time working on an inline so I'll take any advice you can throw my way to get this thing running right.

Thanks for your time.
Chris

Forgot to mention that the vacuum advance on the distributor seems to be working correctly. When gassed, the distributor pivots slightly under the vaccuum pressure.

What kind of choke(s) do you have?

Adjust the valves.

After adjusting the valve, if you have a vacuum gauge, set the timing to maximum vacuum and set the carbs' mixture to maximum vacuum (all at idle). These are not necessarily optimum settings but they are close enough to get a smooth running engine/truck.

That vacuum gauge has a large readout and a variety of engine diagnostics printed on the face.

The choke on one carb is pinned open, and the other is a manual choke operated by hand from inside the car.

That works fine for me with dual original-style Rochesters.

It might need heat to the carbs. There are a couple different options for getting heat to the carbs.