I recently bought a 1985 F-150 with a 5.8L HO Windsor and a Holley H4-4180 carb. The guy I bought it from was trying to get rid of the emissions on the truck as it was a farm truck and it's running rich. I'm not sure if all the vacuum lines are hooked up right. I'm not a vehicle mechanic and I'm trying to fix it myself. Does anyone have any suggestions on where to start?

 

Start by reading the caption of this diagram:



...filling in your signature (https://www.f150forum.com/profile.php?do=editsignature), and posting a LOT of clear photos (follow the link in that caption to learn how free). But I'm guessing there will be too much missing for you to fix it right, and you'll end up having to finish what the PO started to get it running "better".

 

He might have eliminated the PCV valve which will give you a rich condition, especially at idle and low speed. I've seen people do this thinking it was going to make a power and/or mileage improvement.

 

I'll post some pics. so you guys can see what all is there and what is not as soon as I can get back to it. Does anyone know what the compression should be per cylinder on the factory engine? I haven't even had time to check the compression yet so thought I'd make sure I don't have a burnt valve first.

 

135-150 psi is typical. Probably more important is variance. A healthy engine will have all it's cylinders within 10% of each other.

 

Pressure is not specified because it varies with local barometric pressure, and MANY other factors. Read this caption:


(phone app link)