Technical SBC guys, help me get my 283 runnung right before i put a match in the gas tank

So about a year ago i pucked up a survivor 39 deluxe coupe out of long indoor storage with a bad flathead. My last five cars were flathead cars so i really didn't want another one. I decided to do an early 283 although i hadnt worked on a SBC in about 40 years. I picked up and early 60's 283 that was running but tired.All complete and never been rebuilt.I ran it on the engine stand a bit, noted it had a misfire under acceleration but it had been sitting for years,old plugs and wires etc and as i said it was tired.Fast forward 6 monthes, had the block cleaned and machined 40 over,crank was good so just had it polished.Had the powerpack heads cleaned and machined , reused the original valves and springs at the advice of the shop. Put in an rv type cam frpm summit,new lifters,pushrods and rocker arms.New timing set cleaned up the orig dist and carb,new points and condenser, new wires. Before i installed the engine i put in a new gas tank ,carter elect fuel pump and fuel line so no dirt and rust.Included a wix inline filter. I found tdc before installing the heads and marked it on the timing tab and dampner.I also ran the engine on a stand before putting it in the car. Primed the oil pump , put in break in oil etc. The cam and lifters were luber with isky moly lube. Motor started right up, seemed to run fine although i could tell it needed some tuning.Ran it at various rpm's during the app ropriate break in time.OK, get the engine in the car,fires right up no backfiring or weirdness.Go to take it for a ride and it dies as soon as i get on the gas,then comes back a bit but breaks up and misfires and essentially runs like crap . I've rebuilt the carb ( rochester 2 jet) with a quality kit from mikes carb parts.It was cleaned thouroughly ,soaked in Gunk carb cleaner etc,blown out with air, new accelerater
pump all new gaskets. I replaced the dist with a remanufactured one,changed to a mallory condenser, new plugs. Messed with the timing for days,checked that i didn't wipe a cam lobe,checked the valve timing over a few times,checked the firing order multiple times switched coils , bypassed the ballast resistor and a bunch of other things i can't even remember. I should mention that i mounted the carb on the intake backwards so i could use the original early ford throttle linkage. I know this is a trick thats been done forever and shouldn't effect function.I had to machine a special adaptor plate so the carb base would,'t suck air.Also i checked for vacuume leaks and could not find any. I get about 16 inches of vacuume which goes up and stays steady at higher rpm ( i thought i should lose vaccume when the throttle plates open ,not increase it?) Anyway, if anybody has any thoughts i would sure appreciate it.
By the way, the carb was a parts house rebuilt unit when the motor was removed from the original car a few years back .I had been run for a while but not much. It looked clean inside but i don't have much faith in the rebuilder. When i took it apart to rebuild it again it had 2 different size main jets in it..

Some questions : How do i determine if i'm having a fuel delivery problem or an ignition problem? Tweaking the timing does nothing to fix the problem.
Can a carb as simple as a 2jet just go bad and not respond to a rebuild?
How does the new cam impact tune up specc's like timing and vacuume?
Just to be clear, this engine starts up in one revolution or less and responds well to the throttle when the car is stationary.The trans is the original 39 ford 3 speed.

HELP! i should have been driving this car months ago!
Don't make me go back to another Flathead !
Thanks in advance guys for any help
Bob

 

The vacuum sounds about right for a mild cam. It'll increase with rpm as long as the throttle isn't open very far. With serious throttle the vac will drop way down.
Have you tried a totally separate power source to the coil-like right from the battery (include the resistor) to rule out wiring trouble? If you have a manual choke that would help diagnose a fuel issue.
This intake doesn't have the exhaust ports that come up into the carb base does it?

 

For starters, try 16 BTDC at idle with the vacuum disconnected and plugged - until it runs better.
Verify the accelerator pump is squirting.

Did you replace the points and condenser? Start there with good parts from Napa. The condenser may be bad, which will make it stall under load.

 

Thanks for the response!
I have tried hooking the coil directly to the battery,no change plus i checked the voltage from the switch to the coil a dozen times and it's fine. I have rewired the entire ignition circuit.Carb is set up for a manual choke,squirters are squirting Put in a new accelerater pump when i rebuilt the carb. The intake does have the exhaust ports on the carb base. Is that a problem? They are clear and i used the correct base gasket on the carb.

 

Thanks for the response!
I have replaced the points and condenser and yes, with napa parts and also a mallory condenser. It really does feel like a condenser issue,which i have had in the past. I have played with the timing to the point of being rediculous and have had it advanced that far. Timing has made NO difference with regard to the problem.I'm back to about 8 degrees now which seems where it runs the best but still cuts out and breaks up under acceleration. I've also switched out the distributor for a reman one. No difference. Squirters are squirting

 

When you said you turned the carb around backwards, you mean the floatbowl ended up towards the rear instead of the front of the engine. If that's correct, you might try accelerating slowly to see if it runs okay. What could be happening is the main jets uncovering under acceleration. Holley mechanical 4 barrels would have a stumble under hard acceleration as all 4 barrels could be wide open, and fuel would slosh away from the secondary jets. Holley make extension tubes for this.

You may have to turn the carburetor back around to the normal position and reconfigure your throttle linkage.

 

What is your fuel delivery pressure? What is your fuel delivery volume? Does fuel delivery pressure nose dive on acceleration?

 

Thanks for the input!
So on a rochester 2 jet,the bowl is very narrow front to back, maybe 2 inches at the most . with the main jets down in a well at the bottom.The bowl would have to be just about out of fuel for the jets to be uncovered. Also, if i take off real slow it sometimes doesn't die out but will start missing badly as soon as i give it the fuel. That is a good point though . I think im getting way too much furl volume for the bowl to be that low on fuel.I'll triple check my float setting again.I am thinking of maybe turning the carb around and changing direction of the throttle shaft (if thats possible)

 

I have no fuel pressure gauge so the only thing i have to go by is the manufacturer's spec. I think from 4-6 lbs. of pressure.Carter says no pressure regulator was necessary. As far as volume, i can tell you it will fill up a coffee can in about 15 seconds so volume seems fine. It doesen't come out of the line with much pressure at all.

 

I hate to be the one to suggest this but.....how bout swap out the points & condenser in the distrib with a protronix to rule out the old-style unit..... The coil they recommend is 40,000 volts. With new wires it should be a bullet proof ignition.
Still no fix??!......Then look harder at the carb/fuel system. (fuel pump and filter to the carb in good shape?)
6sally6

 

Thanks,
I have thought of that but truthfully i've been running and dealing with points type ignition systems for over 50 years amd have always been able to manage pretty well.In this case i have tried 3 condensres,3 sets of points , 2 caps and 2 rotors and a whole new distributor.None of it has made any difference so i find it hard to believe all those componants could be bad. Fuel pump is new,fuel filter is new,fuel tank is new and fuel line is new.I've been thru the carb twice ,again no difference.. These carbs are very simple so not sure what else i can do there.Pump seems to be supplying plenty of fuel.

 

Might want to verify you have good ground to the frame, battery and engine, also check the continuity of the wire from coil to points , actuate the vac advance while checking

 

Check float, not just setting, but make sure it does-float. Original brass could get pinhole and partially fill--been there/done that. Could be getting too much fuel, due to overfilling bowl.

 

I’m a little behind.
You bypassed the ballast resistor?
So are you running points on a 12 volt system?

 

Regarding the exhaust holes in the intake....if the exhaust is getting into the intake air you will have a problem. I'm not sure how things line up with the carb turned around so you'll have to look carefully to see. It's probably not your issue but worth a look.

 

Thanks, put in a brand new brass float when i rebuilt the carb and checked it for leaks.

 

So the holes for the exhaust match up the same without regard to which way the carb is facing.I checked that with the gasket when i was making the baseplate to mount the carb. By the way, are those holes really necessary?

 

No, not necessary.

 

Yup, bypassed the ballast resistor temporarily just to make sure i had no issues with the ignition circuit, which i had completely rewired already. It was a temporary test.

 

So if i wanted to, i could make a new solid base plate that would seal those off with no negative effect?

 

Thanks, all that has been checked

 

Try backing off the rocker arms nuts 1 turn and see if it helps.

 

Yes, those were used to provide exhaust manifold heat to warm up the fuel mixture quickly. Just plug up the
holes using little plugs, like the ones they sell for oil passages. Here is a 4GC baseplate that has them blocked
off.

 

Maybe a partial turn, 1 full would take a normal engine right out of adjustment, but good idea.

 

Okay, i did recheck the valve lash but maybe i'll loosen them all like a quarter turn.

 

Thanks, i'll loosen them up a bit

 

I disagree carb heat is a good thing for proper atomization. The cast iron bases were the best. With todays fuel the passages with never carbon up.

 

I am betting it is fuel related. I am betting it is a vacuum leak. When you have checked EVERYTHING and found NOTHING, check again for what you missed.
per Percy Schook, " this ain't no oujie board, boys".

Ben

 

So ive been checking for vacuume leaks for 2 months and haven't been able to find any. It seems a vacuume leak weather the engine was under load or not . Also, been thru the carb twice ( that still don't mean its good) but i don't know what else i can do regarding those 2 issues.

 

I have no issue with keeping them as long as they are not adding to the issue i'm haveing.