I'm getting like 8mpg on my '79 302. That's not very good. I'm planning on putting on a 4bbl Edelbrock carb and aluminum intake so i can get rid of all the EGR equip. I'm also trying to get headers for it. Is there anything else i can do for gas milage? I was also hoping to switch over to a 4 speed tranny for milage reasons too.

 

Can anybody help?

 

What's it in? Somethings wrong for sure if it's in a half-ton, my '78 302 with a C4 and 3:00 gears got a constant 20 MPG highway. Bone stock with 2 bbl, and single exhaust.

 

It's all stock, iknow the carb is all messed up, hence why i'm replacing it, but everything else is stock, all i could figure was 1. Vaccum leaks, and 2. Old Emission equip. Hence why i want a new intake so i can remove the emissions, i really would like 20mpg.

 

4 bbl (if you keep your foot out of it) with smaller primaries, Edelbrock or Weiand alum intake, headers, dual exhaust, new plugs gapped at .045 new plug wires, new rotor and cap for the duraspark, set timing at 10 deg BTDC.
Hows that for a start... should get you up in the high teens at minimum on an F100.. what's your gear ratio?

Make sure your Duraspark "Brain" on the fender is good.. that's the one thing I had screw up that might cause your problem

 

I can only see one notch on the pully that powers the thermactor system, i assume that's the timing notch right? How would i know if my duraspark "brain" was good? High teens would be amazing as this is my DD.

 

Mine didn't have a thermactor, in fact the heads had the thermactor holes filled from the factory. The timing marks are on the harmonic balancer at the end of the crank.Wipe the whole thing off with some Varsol if it's dirty. There's a little tin piece that comes out from just in front of the dipstick where you read the timing. Go get another Duraspark "brain" from the wreckers for $10, make sure the colour of the part where the plug goes is the same as yours i.e blue, brown or yellow. Cheap way to check. results will be immediate.

 

Which peice of aluminum? The one that looks like a pointer? Cause that's pointing past the harmonic balencer too the other pully. Would it run bad if the brain is bad? Cause mine runs alright. My underhood label also says 6* BTDC, should i still go for 10?

 

Mine ran as though it had a fuel starvation problem. You dam near had to hold your foot to the floor to keep it running. The flat edge of that tin piece on the fan side is where you read the timing. (You, of course, need a timing light to read it). The retarded timing at 6deg is for emissions. Dirty it up a bit and set it at 10.

 

While you are at the wreckers try and and find a similar carb to the one you have for cheap.(assuming of course it is not one of those crappy variable venturi things). With the brain and the carb you might be able to fix what you have for around $30-40 bux.

 

I'm rather get the 4bbl anyway cause i want the new intake to get rid of emissions, plus some more HP would be nice. I don't really have to hold my foot to the flow to keep it fromstalling, but it does backfire a little at low rpm.

 

I take it a msd distributer and ignition box would also help HP/Gas Mileage right?

 

It woudln't hurt. It might not make a difference though.
What is the motor in?
What are the tires and gearing?

 

My 79' 302 gave me the same gas milleage - 8mpg. Here is what I did:
1) Replaced worn out Carter AGFB with Edelbrock 600 cfm. I went a slightly bigger carb mostly due to availability at the local store and that I did not want to spend the time to rebuild the carter. I don't think I got any EGR stuff. You can meter the carb for the same spec as the 500 cfm I think - not sure about pros and cons.
2) My tires were way under-size - they were 215/75/R15. I went 10.5 X 31 X 15. That's a little bigger than stock, but much better than what I had. That was a major factor towards my gas savings. Of course, I have a high rear end ratio. Probably 4:11 and that does not help much.
3) Timing chain was about shot, so replaced that.
4) Get this: gas tank had holes on the top ! Replaced that as well.
5) Replaced worn out fuel hoses.
6) Fuel pump seemed to pushing more than 6psi. So, installed a pressure regulator.

Now, after all these changes, I get about 12 - 15mpg.

Next in line is a distributor change. I cannot latch on to the timing. I am hoping that after that, I will get some more milleage. Also, on the plans are a set of headers and dual electric fan. So, I will see what I end up with.

 

Yeah, i was thinking about a regulator. I think i have 10.5 X 31 X 15's but my speedo is way off i think. And i'm gonna get the summit Edelbrock and Carb combo.