Have 1957 Ford T bird with 312 engine. Runs great cold warms up and starts missing when accelerating.
Ignition points, coil, spark plugs, ignition wires, bad fuel, carburetor needs rebuilding… All could cause a miss.
In 1957, cars needed spark plugs, points and condensor, Inspect cap and wires, chech dwell and reset timing and usually a carb adjustment every 10,000 miles. Also, make sure the choke is all the way open when hot and make sure the exhaust heat riser is not frozen shut.
And the fuel system was not designed for ethanol fuels.
Depending if you want to keep it pure stock or not. I would replace the ignition system with a modern pointless system and either go with a new carburetor designed for ethanol or a throttle body FI system.
Those had some choke problems too, or at least ours did, so check to make sure the choke is fully opened when warmed up. A good ear usually tells you if a miss is spark or fuel.
If the choke isn’t causing the problem check the exhaust heat riser valve and the entire exhaust. A restriction in the exhaust on either side will force exhaust gas under the intake and overheat it. Often the heat can get severe enough to make the intake crossover glow.
Vacuum advance hose shot or diaphragm broken? Suck on the hose and see what’s happening under the dist cap.
I would check the vacuum advance too. I had a leak in the diaphragm on a 69 Skylark, idled fine, would bog down as soon as you gave it gas.
The bird only does this once it fully warmed up…runs great cold.
How long does it take to fully warm up?
Some 312 engines had 3 thermostats, 2 in the block behind the water pump and 1 at the intake. One of the block mounted thermostats can cause the cylinders on one side to overheat and miss without affecting the other.
You may need to go to a nursing home to find a mechanic with the right experience to troubleshoot, or get in touch with Jay Leno.
NURSING HOME… I resemble that remark. I have worked on mid 50s Fords including T-Birds with Mercury 312 engines and hope to be busting my knuckles 'till I run out of gas… But realistically getting that car properly taken care of could require a ‘seasoned’ mechanic who enjoys getting under the hood of one of the great cars from the past. And I enjoy a challenge occasionally as do my ‘seasoned’ friends. Asking around for recommendations in the area might be worthwhile.
BTW, does the car have a 3 speed manual?
Funny you should think you need to go to a nursing home. In Automobile magazine this month they had an article on McPherson College in Kansas. They have a four year degree program for automotive restoration. They only take 40 kids a year but they learn all about the old cars, car history, body work, painting, engines, interiors, etc. Plus they have to take the normal course work for a liberal arts degree. Sounded like the grads do quite well and are sought after by car museums. Jay Leno is a supporter. So I dunno, maybe drive down to McPherson, Kansas and have the kids take a look see after class.
Even though I was dying for some practical articles like body work and painting, this is the closest I’ve seen and I’m still not renewing this subscription either.