Thanks John. The timing marks are on the pulley. It does have power brakes, but I disconnected the booster and blocked it off to eliminate it as a leak source. I do not see any fuel leaking from the large screw, but occasionally there will be a little bit around the vase of the two vertical tubes. The only time I see the one rear bowl fill is when the secondary butterflies open. It will hold the fuel until I manually open the butterfly, so I think they are fully closing. While I do think the carb has issues that need attention, could it be bad enough to make the manifold vacuum half of what it should be?

I'm still puzzled why the the timing has to be so far advanced for it to run. I had mentioned before that when the previous owner had it in a shop (foreign car shop, don't know how much they know about Y blocks) that they pulled the timing cover to check it. It could be that they were expecting to see the two dots on the gears lined up, which I understand is not correct for a Y block. So it may or may not be right. That said, with the balancer at the TDC mark, both of the rockers on the number 1 are loose, so the lifters must be pretty close to the bottom of the cam lobe. Also, when at the TDC mark, the rotor is pointing to number 1 on the distributor, but I guess that you can stab the distributor in any orientation.

I'm going to pull the rocker shafts this morning to make sure that none of the pushrods are bent. They spin freely when relaxed and all the valves look to travel as far as you would expect when the cam turns.

i was having a lot of trouble getting mine timed, i'd rotate until i got tdc on the compression stroke, look at the rotor and it'd be pointing somewhere around 1 on the cap. wouldn't run. finally i was told to rotate the engine to 10 tdc (i basically guessed as my damper has no numbers on it), loosened the distributor hold down, and brought it counterclockwise until the rotor was pointing at #1 and the points were open. that got the engine running pretty well. i realize you don't have points anymore though, so i don't know how you'd know when the pertronix would be "open" or sending spark...

Be aware that no.1 cylinder is the front passenger side, ie. on the left looking at the engine from the front of the vehicle.

.


South Australia

remember if you upgrade the distributor you have few options re the tack drive(just 57 tbird)and the newer carb must go with it.like others the original 55carb and dist can work well. is your vacume advance ruptured? is the vacume valve for dist working? the earlybirds need lots of inital advance even when all elce is working ,sounds like some good advice re power brake and othe vacum leaks . get hold of a 55 56 motors repair manual they explain the carb and dist advance process. i had 2 55 birds and made the last one run great with original carb ,dist,and points and 6volt. 1st 0ne came with elct.tack so any 57dist worked and 57 int manifold and carb ran well but i prefered the the purest rout. be patent and it will be a fun project

What do you mean by vacuum valve to disributor?

Update: Pulled the rocker shafts and ensured that all of the pushrods are straight. Reset valve lash at .019" with everything cold. Started back up and valves were quieter, but vacuum now in the 7-8 range. The previous shop had it set at .035", maybe in an effort to increase the vacuum, not sure. Anyway, it still has the same miss. I did notice that the rotor had a ton of play (the shaft itself seemed fine), so I will see if I can find another rotor that fits better.

I did make a discovery that will hopefully lead to a solution. I scanned all of the inlet ports on the exhaust manifolds and realized that there's a problem with #5 & 6 cylinders. The other six cylinders were between 400 & 425 degrees, while #5 was about 190 and #6 was 285. Both cylinders were getting good spark and the plugs were not fouled when I pulled them yesterday. Compression of both cylinders were in the same range as all the others, so I think the issue is that that corner of the engine is not getting enough fuel for combustion to occur. That has to point to either a carb or intake issue, I would think, but would sure like some other opinions.

Thanks again for all of the advice.

Doesn't sound like a carb issue, because 5 and 6 are fed from different sides of the carb. Cylinders 1,4,6,and 7 are fed from one side of the carb, 2,3,5, and 8 from the other. A lack of intake manifold seal at the left front could be a problem Hey! I just got an idea. If the front valley cover bolt is sticking up too far, the manifold rests on the head of the bolt and doesn't pull down tight. A lot of front ears are broken on Y manifolds because of this. See if you can slide a thin piece of metal or cardboard between the bolt and the manifold.

John - "The Hoosier Hurricane"

Did a test for vacuum leaks this afternoon with a homemade smoke machine, but didn't see anything leaking. I'm going to pull that valve cover again and watch the rocker movement on #5 closely.

I'll look closely at the valley cover bolts and see what I have.

Thanks.

OK, the issue on 5& 6 is solved. I seemed to swap those two plug wires when i reassembled it this morning. I meant to do a continuity test then, but got sidetracked and forgot. Vacuum is back in the 11 range, but it has a bunch of initial advance. When I crawled underneath to investigate an exhaust leak, I did notice that the rear main seal is leaking badly and there's a good bit of smoke vapor coming from the road draft tube, which makes me think it must be seeing a lot of crankcase pressure. Not good.