The Evap systems primary function is to keep the fuel and fuel vapor trapped in the system, and from leaking to the atmosphere. The biggest benefit is that it keeps your valuable gasoline in the tanks where it belongs instead of evaporating away. It also keeps the truck from smelling of gasoline on a hot day. If you have ever parked next to an older vehicle from the 50's let's say and smelled fuel, you know what I mean. The system also alows venting of the tanks and the carb fuel bowl when the truck is running.

The various lines from the gas tank(s) and carburetor fuel bowl goes to the charcoal canister where the evaporated fuel vapor is stored while the truck is parked.

Once the engine is running and under the right conditions the system purges the charcoal canister of the fumes and they are burned in the system. After the purging of the fumes, the charcoal canister acts like a one way valve. It alows fresh air to enter the system through the activated charcoal. Fresh air can pass through the charcoal but the gasoline vapor (fumes) cannot. This is the secondary reason for the system the lines to the tanks and the carb fuel bowl are the vent lines.

So the primary function of the system is to trap evaporated gasoline and store it so it can be burned later. Simular in theory to an overflow tank on a coolant system. Then once the truck is running the secondary function alows the tanks and carb to be vented. This alows a closed vented system for the vehicle.

There are some parts differences like non-vented pressure sensitive fuel caps for instance. These fuel caps do not normally alow venting and hold pressure. However if the pressure gets too great they do have a safety release alowing air or vapor to escape. Putting a evap fuel cap on a non-evap equipped truck can have concequences. Colapsed fuel tanks or severe vapor lock are just a few that I've seen. Also I've seen people plug the vapor lines and wonder why the vehicle vapor locks etc...

So hopefully that explains the evaporative system in more detail.

Personally, I'd leave the system intact. It does not rob power from the engine, it saves your fuel from being evaporated into the atmosphere, and improper removal can cause bad side effects, so the benefits outweigh the removal in my opinion.

Good luck.

 

Thank you! That was very informative! There was not a line to the carb when i bought it, sounds like i should run one though. Can i hook one up to an aftermarket carb?

 

Looking at Nicknames. I couldn't give that truck a Female name. I'd have to call it something like Rusty. (not because of damage, but because it's red). But I agree most nicknames don't come around until you're driving, and working on them. I got my Grandpa's bronco, and after he died, I refer to driving it or working on it as spending time with Grandpa. and some of my other cars just get cursed. but the Bronco will come First.

 

after 3 coats of paint......here's the final product and its amazing how much paint can change everything.

 

here is the new 302 ready to be transplanted in

 

Ahhhhhh yeaaa.....Thats a SWEET lookin' engine...

 

Thanks dude! Hopefully if im not too tired from work and the rain holds off, I'll have it in and ready to roll by Monday

 

What intake is on that motor? It looks like a performer rpm or possibly a Victor Jr. That style of intake is for high winding 1/4 mile cars. Not for low end torque like a truck motor needs. Especially an off road truck. You need a dual plane instead of a high rise.

 

The intake is the summit stage 1 intake.

 

Well its listed as a dual plane and says the power range is from idle up. The intake runners look really tall that picture you put up. I had a really tall intake I got in a trade. I was going to run it until I found out that it wouldnt even do anything until 3500 RPM. So I ended up selling it and finding a used Performer. That Summit intake had a really good price on it when I looked it up. The next build I do I may use one of those.

 

I agree, the runners do look really tall in that picture, but they are not, I will upload another picture for you. I've used the summit intakes on many applications and only have praise for them and for the price you cannot beat it.

 

Most aftermarket carbs do not use a evaporative emissions system. So if your carb does not have a port for that, it would be fine to delete the fuel bowl line from the canister, just make sure you have the others from the tanks hooked up and some way to purge the system with the PCV valve etc. The small port on the PCV valve etc, and the canister purge valve, little round looking bluish green plastic thing with three nipples.

Shouldn't be too hard to do.

 

sorry its been a few days since I've posted, worked the holiday

hope everyone had a Merry Christmas!!!

here are the headers i painted and sandblasted....not in that order



here's the motor in finally
im amazed at how significantly smaller the 302 is compared to the 351.



and I'm not sure what this thing is, it was in the oil pan and it broke when we were installing it, any ideas?

 

It looks like a nylon anchor that would be used in drywall. But I doubt that's what it really is. Surely not. Maybe I can't see it well? Can you take another picture from a different angle and/or closer?

 

surely, I took several more, here ya go!