I recently tuned this motor and carb to perfection. Seriously, I set everything to get the best MPG's and performance possible, rebuilt carb, jets, float adjustment, de smog etc etc etc. This motor is .60 over, 260 cam fully rebuilt longblock with 5000 miles on the clock. This header came with the old motor and I have had it on since. The muffler is OEM. Someone stole my cat so its not there
What my issues are: I would like to get better MPG's I am around 17 right now and I would like a little more power.
Who makes this header? Is this header holding me back? Is the exhaust and issue? If so, what would you recommend to pull better milage and power?
Thanks

 

for best mpg, run all the oem stuff. Tire size and gearing also play a huge roll in mpg. And Just fyi, there is no real Mpg and power setup. Its either one or the other with these trucks

 

yes I understand.
I thought the LC Headers helped with MPG? I noticed a few MPG more on my 94 after I put and LC in it.
On these older 1st gens you think running the stock manifold, stock all the way back will help with MPG???

 

anyone on this?

 

I personally think tubed headers are better than the cast stock ones.
That one looks in decent shape. Unless there are any exhaust leaks I'd say it's good.

 

No way. The first gens were so choked with "emissions" B.S. you were wasting power right and left. Your engine is way underpowered/choked you're gonna floor it every time just to get up to speed at a reasonable rate. If you have it running with some higher HP you won't have to giv it so much gas to get going. People will blow holes in this argument all day (go right ahead guys) but from my experience, my best mpg wasn't at stock or at my present config, it was a middle ground on my way to dual sidedrafts.
That being said, I don't know what brand those headers are, maybee downey's? I have a nwor tri-y on mine that looks similar and I have been quite pleased with it for many years. I can't remember what all you have carb/intake wise, but my best mpg in the '81 was stock gears, webber 32/36, offy dual plane, tri-y, trd s2 cam, stock gears and 31's. Totally de-smoged of course.
I don't know what you can get away with being from the land of the smog nazis (cali) but I feel most of that stuff (especially the early versions) just hurt. Hopr my rant helps in some way.

 

555y-c doug thorley headers

i'm getting these (today, actually)

 

Oh, you said you de smogged. If those pics are current you need to block off the air inject ports?(don't know what they're really called) on the top of the headder flange (shown in the top 2 photos). You don't wanna be leaving those open. Other than that they look fine.

 

You mean that hole in the upper left hand corner? I don't think there is anything behind there? There is no exhaust leaking there. At least I don't hear it. I don't think there are any threads there either. what do you suggest?

 

those are emissions crap stuff. if you can stick a pencil in there and it goes deeper than .5", you need to block it all the way off.

 

IMO, that looks like the tri-y from NWOR, similar to the thorley's. I'd leave it. That will help with low to mid range torque which is everything in city MPG, and shouldn't be any worse then an OEM manifold highway wise.

Opening up the OEM exhaust piping to 2 1/4 and throw a free er flowing muffler on will do you wonders as well.

 

thorley:



nwor:



definitely dt's, possibly ceramic coated.

 

Yup, closer to the DT's I guess I will have to agree. Only thing is toyo's don't look coated??

 

i probably just don't know what ceramic coating looks like

i will this evening, though

 

I am just guessing based on the surface rust of the header. Either way, I'd leave em.

 

I agree
I knew it wasn't NWOR by BOTH flanges. Definately leave it on. 2" or 2 1/4" pipe and a better muffler would help as well.

 

DANG I wish my header looked as good as that one above.
Thanks for the help!
I pulled the rig in out of the rain and did a number of tests on the dizzy. Turns out my numbers are 64!!! That is not good. TOO advanced, WAY TOO advanced. FSM specs are 42. I did mechanical, ignition and initial timing. 38 vac on, 20 vac off connected to manifold and initial is 6 that = 64! DANG! This dizzy is less than 6 months old from NAPA. It is a NAPA re-man. Our napa here is great. I do so much business in there they opted to refund me. I just ordered a new Dizzy from LC.
No wonder I was having MPG issues

 

Don't worry, there's nothing behind there. That thing with the hole in it is a block plate =)

And Bingle - you are right, those are called Air Injection Ports, or PAIR ports.

 

those plates block off the air injector. I beleive you are supposed to have an air injector if you live in cali depending on the year of your truck.

 

Like someone already said the weber 32/36 is supposed to increase mpgs from the stock Asian, but from reading up a 32/36 is better suited with a stock motor, since your motor is bored and cammed, you would need to order a jet kit with some bigger jets.