This is my first question on this forum, so please bare with me. I have been looking
at this forum for about 2 months, and there is a lot of good information. This question may have already been ask. But I thought it would be a good time to get my feet wet. While changing spark plugs in my 1976 360 4x4 I can't seem
to get back plug on drivers side out. The brake line is in the way somewhat,
but I was able to work around it. But can't seem to break spark plug loose.
I sprayed rust loose around it. but did not help. Would it help to start engine and let it get hot? My engine had been rebuilt before I bought the truck. It has a 4 barrel carb. and it runs real good. I don't know what else was done to engine. While I had the no 1 plug out I turned engine over so no 1 piston was at tdc. I measured the distance from the top thread of the spark plug opening to the top of the piston. The distance was about 1 and 1/2 inches. I then
turned engine over until no 1 piston was at bottom of stroke. Then I measured it again from top thread of the spark plug opening to the top of piston and the distance was 5 and 1/4 inches. The difference is 3 and 6/8
inches, which is about 3.75 inches. A friend of mine told me I could measure the stroke this way and it would tell me if my engine had been changed to a 390. Can anyone tell me if this true or do you have to go in to the engine to tell.

 

3 3/4 makes it a 390, 3 1/2 makes it a 360.

And like you said, the spark plug is hard to reach. It could be that someone gave up on it before, and did not change it when the others were changed. All I can suggest is to get a cheater bar for your spark plug wrench.

Also, there is a good FAQ link for this section http://www.clubfte.com/users/ratsmoker/FAQ.html

Welcome aboard and keep asking questions.

 

Sounds like a 390 crank with a 3.78 stroke. As ***** said try a small breaker bar. I use a lenght of copper pipe sometimes for better leverage. The plugs are just hard to break sometimes and this one being rusty isn't helping. After time the rust spray should help. G.

 

Take a blow nozzle hooked to an air compressor and blow away any accumulated crud in that area so that when you do get it loose nothing falls down into that cylinder.

 

Thanks for the info. I will continue to spray rust remover around the spark plug and try
a cheater bar. I used the air compressor around the plugs before I removed them
I could not believe how much trash came out.