I'd buy a Manuel cause there's lots of little things you'll need to know. If the distributor hasn't been removed yrs it may now stuck in the lower part of the block. If engine oil has not been maintained good or the wrong type of oil used. The distributors should move back and fourth while twisting pulling up is the way to remove it. Sometimes it's best to have the motor fully warmed up for it to come out if engine has a lot of sludge buildup in it. Now with any luck the oil pump drive rod will Not fall into the oil pan. Then you'll really be using those 4 letter words. 1. you'll have to pull the pan not ez. That's a thing that you'll wish you never started, a ton of 4 letter words used doing it. 2 Try fishing the rod back out with a flash light and a long handle magnet. There's a little washer retailer on the oil pump drive rod that slides down the rod, causing the rod to move to far up and lets the down of the rod shaft come out of the oil pump as your removing the disty pulling upwards then it falls into the pan area. When this happens most guys don't know it happens and when starting motor they find there's no oil pressure. You must look down in the block disty bore at the end of cam gear where disty end shaft drops into pilot hole to see the little hex 1/4" pump rod shaft tip end. Don't see you'll say those bad words for maybe a week. Okay 3rd way is to get another pump rod and remove retainer washer clip, then use some RTV to hold it in the disty shaft hex end where it fits into. But you must let it setup good so it will not slide out while re- installing the distributor when putting it all back together. Then more luck is needed when the first crank of the motor if you just left the old rod lay in the pan, cause the turn of the crankshaft will bent or push the end through the pan. So best to fish it off remove it.. A good manual is Haynes repair Manual Ford pick-ups & Bronco 1973-1979 #36054 covers the fe motors. Look on ebay. my 2 cents..orich

 

Ouch! What are your plans for this truck?...restoration, working it, or just a fun ride? Reason I ask is the knocking you described is not a good scenario. If this isn't your daily driver, I would acquire an engine hoist and stand and get ready to pull and rebuild it after you run a compression test. From what you describe, I bet the comp numbers on 7 & 8 are gonna tell the tale...time for a rebuild.
Good news is you can get a running, used replacement for probably less than $600, or a rebuilt long block for about $900. That's about what I can get both for here in Texas...302, 352, 360 or 390 doesn't matter.
I wouldn't spend a lot on what you have unless the compression test tells you it's sound.
With a hoist and stand you can do most of the work yourself...from an engine swap to a manifold change. And as Orich says...get a good manual soon.

 

Orich and tmcalavy:
Thank You fellows for your inputs.
I´ll definitely going to get that Haynes Manual.
I´ll consider to swap engine instead repairing this one. That´s a pity because this truck have matching numbers and only 79,650 miles since new.
Anyhow, remember I´m in the Caribbean, so here is not simple and easy to get spares for this old trucks.
I really don´t mind to purchase an engine but need to think that it will be ship out (by vessel) and pay some import or duty taxes. So, having that in mind, is there another engine from another Ford Vehicle that can fit into this truck? I mean like Ford Explorer, Crown Victoria, Expedition or any other like Isuzu.... I know theres a buch of these vehicles around here and getting an engine won´t be so difficult as trying to import one from the states.
Thanks again guys,

 

can you give a little back ground on how you got to this back fire issues or problem before that. or did you buy it with these problems. Was it running? if so did you hear any knocking? Cause what you have going on now sound like the intake gasket. 7&8 have a heat riser port between them. The gasket get extra heat in those areas of gaskets ports 7&8-2&3 cyls also and when these cylinders spark plugs get oil fouled wet it's 99% of the time just an intake gasket. But a bitch to replace for a one man job with out a cherry picker to R&R the intake if your not a young man any more. Hell I'm on my last legs now at 68.But my old truck gets me alive. The aluminum intake is only 35-lbs this why so many guys go with them but still not with there problems. I like the power the fe motors can make but I hate the design it.,,
orich

 

Orich thanks again for your much appreciated father-to-son advise. I´m almost 44 with a vertebral hernia, so lifting weights it´s prohibited for me. I definitely need another guy on this project.
Well, I´ve got the truck like it is. Tru Copart´s auction. Never saw the truck until it came to me here in the D. R. I guess the problem came with it and I strongly believed that this knocking sound came from a broken piston ring in Cyl. #8 mainly because of the long sitting time without firing the engine. Also, when the truck arrived last february, I noticed some water under the carb and all over the intake manifold and inside the air filter, supposed that this was because a missing rubber piece between the firewall and hood.
I really don´t want to swap its engine because I´m afraid i won´t find a decent FE replacement for it here, at least I know they sale motor for Explorers and relatively modern Ford vehicles.

 

..
Not to hi-jack from rusty2872 post, but still on same topic of carb issues+ & backfiring.,,
Gee 69f250 Maybe pull the motor down and rebuild it as needed if you have a knock in #8 cyl. But could be a piston pin ,rod bearing,main bearing.Takes a good ear to tell the difference when you have other issues going on at the sametime the may magnet fie any problems...
orich

 

Well, this sunday i got a compressor tester gauge and this is what i found on my truck:
DRY TEST:
Cyl #1: 135 psi; #2: 125; #3: 130; #4: 135;
#5: 135; #6: 125; #7: 142; #8: 150

Is it possible that the intake manifold gasket has issues or could it be something else?

 

compression looks decent ,
just curious how do you have your PCV hooked up to manifold or ait cleaner ?
have you tried plugging all vacuum ports and see if it still pops ?

 

If #8 was wet oily could be as it has the most compression and next to the heater ehx. riser port. Was your test dry or a wet test. Wet is when a few shoots of oilinto each cyl from a oil can seals the rings from leaking so you can tell the condition on the valves if leaking. Should have carb blocked open for a good pull of air into carb. for your test..
orich

 

Orich: In fact I did a wet test, but didn´t see any relevance in it.
Cyl #8: 165 wet test
Cyl #7: 150 wet test.

MIKES: The PCV is normally attached where it corresponds. I did changed the PCV hose since the later was very old and hard. One end goes to the PCV and into the left valve cover and the other end to the back of the carburetor.
If I disconnect the PCV hose there´s no knocking sound, but the engine shakes.
I already ordered a new PCV.
By the way

 

i have seen strange problems when hooking the pcv tothe back of the carb or manifold .
try capping it off at the carb/manifold and see how it runs . originally the pcv connected to the air cleaner not a full vacuum port .

 

A normal rise in compression with older motors is about 7-10 psi in a wet test then you can figure your compression valves lost. But with what you have should not be causing it to back fire. But running unleaded gas like here in the US will lead to burning up of the vales seats and popping back from the carb under loads..
orich

 

MIKES: Do you think capping off the PCV hose at the back of the carb and on the valve cover won´t hurt the engine?

ORICH: Down here in the D. R. the gasoline is also unleaded. I haven´t drive the truck much, don´t think it will be more than 200 miles, Do you think the valves seats are burned?
The backfire tru the carb is not bothering me much but the knocking sound only when the #8 cyl sparkplug wire is connected. This is the main issue.

 

leave pcv in valve cover , just cap carb port.

 

Ok, will do that and post results...