ok a little background 1976 f250 I6 300cid manual transmission. forward sticker on valve cover is faded completely. emissions sticker says exempt . bought the truck last fall . owner had lowered it put 24s on it and done a bunch of engine work. I wanted to use it as a truck so I drove it approx 20 miles to schwab. bought wheels and tires and had them reverse the axle flip. then it was towed to my home ( a very short drive convinced me that was necessary until front end was addressed). Got the springs also a 14" air cleaner assembly because what was on there was stupid. there was emission hose from oil filler cap to manifold under base of carb (new carb cheap single barrel) i also grabbed a pcv and hose made a hole in the bottom of air cleaner plate and stuffed it in there routed from the hole at the rear of the valve cover which was wide open. no shop or covered area, winter setting in so got done what I could on nice days as far as suspension and the ride height change. There is some rust in the tank, the fuel pump was bypassed with a really simple electric pump mounted directly on the block. and a drip at the pump that took many attempts to resolve... (HOLY ....... i already know... )over the winter there have been some short test runs limited to on my property with a hyper focus on i just need to get to dmv and get the paperwork done before i dump any more money into something that i dont even know if i can legally use it on the road. So as of two weeks ago first road test. only CHANGES was pcv added and air cleaner size. previous drive tests to the back of my property were fine. made it 1/4 mile down the road and it bogged down coughed chugged and then backfired and died. towed it back and now have a crank no start issue . i have gone through everything. and just discovered what appears to be a pcv in the oil filler cap. I had assumed it was a simple 90 fitting as i could find no reference to anything else without added emissions systems. I know enough to know that if that valve is indeed pcv along with the one I added that it could be very bad. I am having a lot of trouble confirming anything and really need some guidance.

 

i did indeed manage to do about the only thing that could hurt these motors now i need to figure out the best way to test while not creating more damage. and be able to determine from said tests what is an acceptable range of poor readings that can be addressed later and what is absolutely necessary to put my truck in "limp mode". documentation helps keep my brain ordered so..... #1 carburetor single barrel obvious leakage at all gaskets also a source of hope because outside mounting stud has a good 1/4 in gap between nut and face of where it should seat and very old rusty with a nice little hook that would have made it a nightmare to get the nut on there. so i see this as of evidence of pressure escape. Sooo options ... parts store in town is the most unfriendly unhelpful ive ever been to and its 4 miles 500ft elevation climb then 4 miles other side. 5 yrs ago woulda been fun challenge. Didnt see anything obvious with borescope in spark plug holes unless all valves should be seated ... kinda seems like should be .. rear seemed pretty clean could read 4 written on piston in the #5 plug. forward lot of gunk lot of oil around threads #1 plug. oil pan might have deformation on drivers side cant really tell without comparison no wrinkles very uniform. just seems like corner is not as sharp as the other side. there was already grease flung everywhere cant really tell if there is more. truck tried to fire couple times so going to narrow my focus to just the carb and hope motor is no worse for wear than my dart was. (loved that car). carburetor cheap chinese so wont waste my time trying to find a diagram or specs. lots of stuff on the property maybe ill get lucky finding a diaphram that will work. have rolls of different films that i will check for fuel resistance that im pretty sure i can make one if i am able to tell what its supposed to look like and isn't shredded. gaskets... um... couple random ones floating somewhere glue it if i have to . springs? maybe don't know yet ...remember to take pics!!! today: tune bike pray i don't need a tube
tear apart carb

 

Welcome to FTE
I wished you did paragraphs to make it easier to read.

Ok lest go back to this PCV and how you got it hooked up.
The valve should go into a rubber grommet at the back of the valve cover. The hose then goes to the vacuum tree on the intake manifold.
The oil fill cap should have a hose that goes to the air filter. I think you said you put a hose to the bottom of the air filter you can stick it there.

I dont know what you got going on with the carb, hard to read, but if you grab it at the top and try and move it it should not move.
The carbs on 240 / 300 motors have been known to shake loose. Think you said something about a gap in a gasket and leaky carb?
Make sure the screws are tight and fix that gap.

If you can post a picture or 3 of the motor so we can see what you got going on as we may see something else.
Dave ----