Back to the old 390 Holley:

As you may recall I jetted up the 60’s, and regained highway performance, or rather that 40 to 80mph passing response band of operation. She pulls real strong with these jets, and feel real good, however I’m now sucking gas to beat the band. Fuel usage is way up with this state of tune.

I’m going to re-tune the idle mixture, and idle speed one more time, but don’t hold out much hope that this aggressive consumption condition will change much. The engine is running rich, but power feels as if it is up at all rpm levels.

Later tonight I’m going to pull a plug or two to see just how rich I’m running.

Second plan will be to remove power valve plug, install 1 inch Hg power valve, and jet down to 57’s. Hopefully this will still provide good passing response, but lean out highway speed band, and idle, thus improving fuel mileage.

Bill

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Bill,

Now you know how to set it up for drag racing........ Good test!
I like your plan to swing the pendulum back a little.
Good work!
You will find the balance that will keep the mystery cam and you happy.

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Fell asleep last night on couch too early to pull a plug.

Ted:
[quote]You will find the balance that will keep the mystery cam and you happy. [/quote]

As long as I’m not making “Big Oilâ€￾ happy, I’ll stay happier…

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

In my experience, Holleys are good for racing, but are very hard to tune for mileage and power, especially with a bigger cam. The 1950s spill-gas-allovertheplace design to change jets/valves is also really annoying.

You might consider trying a BBD or an Edel AVS or AFB 4bbl. AVS is most tunable, and is way easier to tune and more flexible to tune for cruise and power than any Holley. For pure racing, a Holley might be better, but for all around use, there is no comparison to a Carter/Edelbrock.

2 more cents...

Lou

_________________
Home of Slant6-powered fun machines since 1988

[quote]You might consider trying a BBD or an Edel AVS or AFB 4bbl. AVS is most tunable, and is way easier to tune and more flexible to tune for cruise and power than any Holley[/quote]


Lou you’re probably right, and are not the first to one to propose that hypothesis. But, I guess at this point I’m going to play cheap skate, no piker, and keep on with the dreaded Holley, as I have blown my wad on this heap for this year.

Where I don’t race, perhaps before a new carburetor purchase, I should install a more reasonable camshaft tuned for torque and mileage, dropping the power band to a more highway usable range.

Currently the cam I have now likes 3K to 5K rpm for power & torque. 3000 rpm translates to the 60 mph range.


Test drive results:

1 inch Hg power valve, and 57 jets installed give 1 to 6 “ Hg in gear idle of 550-600 rpm.

Not as punchy at highway speed as with 60 jets. Fuel consumption is unknown. I suspect that unless I’m on a hill, WOT that 1â€￾ valve is acting just like a plug.

Spark plugs from 60 jet tune looked in “good rangeâ€￾ on the rich side of the chart. Numbers 2,3,4,5 plug show darker color on one side of center electrode than the opposite side. Ground electrode shows gray to light gray deposit.

Bill

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Bill,

I see a 500 cfm Edelbrock AVS in your future..........
it is quicker to change than the cam.....

Thanks for the plug report. It sounds like you got a real race engine on your hands that your trying to tame....it will take some very fine tuning on the Holley from here on out. Keep a log book of each change so you can go back if you need to.......

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

AG Ted:
Roger that on installing a carburetor. I’ll be checking my stockin the end of December for said carburetor…

Still I suspect a cam change would be less laborious, cleaner, and much easer on the old carcass than this weekend’s flex plate change-out… I’m really starting to dislike pulling transmissions from cars suspended by ramps & jack stands. LOL
I have been keeping a record of what has been done on every repair & up grade in two loose leaf binders containing 10 subject tabs. With each subject I have included different ideas, builds, and systems from this board, and other sources of things that strike my fancy that may or may not come to fruition.

The previous owner, from Danvers, Mass., built this car in the early nineties judging by the title. He started with a 50,000 mile cream puff girly car, and took it drag racing around the north shore of Massachusetts, and pounded on 65,000 miles. The Dart than sat unused for some time until July 2007, when the car went through the Owl’s Head Transportation’s annual auction, where it didn’t sell. From the time of the auction and when I purchased it February 2008, the car went to four owners, two of which were car dealer/repair operations.

I have discovered indications that several quickie patch-up repairs were performed to get it to run & look decent, but not enough to pass a state inspection. Among them; front end work, front disk brakes, and both sides of car were repainted. I suspect each owner soon discovered this little car needed a lot more than met the eye, and dumped it but quick.

Than a sentimental sucker came along looking for a project that could write a check, and has been picking the Board’s collective brains almost daily with each new project undertaken for the last several years.

Believe me; all of your help has been greatly appreciated by this Maineac.

Bill

Ps. Wouldn't a 500 cfm carburetor be a little on the large side for a slant?

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

A bit off topic here, but a quick question for you Bill. You only mentioned the condition of your spark plugs 2 to 5. Are you still running a hotter plug in 1 and 6?

It's been good reading about your 390 tuning in this thread and others, I've learnt a lot

_________________
62 Valiant, 225cid Slant 6/PB 904 with lots of good bits

http://www.moparmarket.com/readersrides ... user=SV162

SV162: You remembered! Yes, Autolite 6 I believe. I numbered each plug using a Sharpy marker when first installed after the valve job 6000 miles ago, so that each plug returns to the same combustion chamber each time it is removed.

Due to laziness I pulled all but # 2 & #5, as the plugs were all looking much the same. I had concern for #4 as that is the cylinder that showed oil starvation to one of its rocker arms that I wrote about in this thread early July. Number 4 showed lower compression by 5 psi from an earlier test, and I’m worried that perhaps a bit of valve burning may have taken place.

My thoughts were; if that cylinder was not functioning correctly, it would show increased deposits from jetting up 9 sizes from the original 51 jets. It didn’t manifest any significant color difference from its short runner mate #3.

As to the state of tune; after changing out the jets yesterday, and starting engine with an empty float bowl, as soon as fuel hit, she fired right up, putt.. putt………putt...putt. I had forgotten to replace four plug wires, and she was happily running on two cylinders, #3 & #5.
I have enjoyed the challenge myself and discussion with all from around the globe, now, do you suppose we could get a reduced group rate from Slant U this semester?

Bill

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Not to ask, but looking over the data, idle characteristics, and vacc. readings...did you map the cam and determine it's installed centerline?
It really looks like the cam is not installed in it's sweet spot... I think
once the centerline has been corrected, the carb will be able to jet leaner
get good power and mileage...and a high vacc. reading as well...

It's hard to get anything close without a benchmark to go from.

-D.Idiot

DI,

I and others have pestered Bill about this already, but good to see another vote...

Lou

_________________
Home of Slant6-powered fun machines since 1988

Some of the guys on this site have found that the 500 AVS works very well. Check their tuning setups. It might get along with your cam better than the Holley.

Reference one of Lou's post....
I believe Lou posted some pretty good mileage numbers a few weeks back like 27 mpg......? :shrug:

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

I and others have pestered Bill about this already, but good to see another vote...

Lou


Ok…OK… OK… I get it. Whip out the old degree wheel, a magnetic held dial indicator, and harmonic balancer puller, and have at it. LOL

I don’t have either a wheel, dial indicator, or proper puller, and I’m not sure where I can bum these items, as most of my car guy buds, GASP!… send their iron out to be worked on for trivial stuff, never mind engine work. Remember, wad is blown on this heap.

wjajr: The method of measurement I will pester you guys for, as well as how to make any angular corrections if needed.

I shall embark on a mission to scrounge up those elusive three items without spending a dime. Car show Sunday, it’s possibly a fertile ground for tool procurement…

So Lou, are you running a 500 cfm Edelbrock AVS? Is this carburetor their Thunder series Summit has listed as EDL-1801?

Bill

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

You can print-out a degree wheel from a few different web sites.
With that, pull the valve cover and find the intake and exhaust valve opening & closing points. (at your current lash and at .050 lash setting)
We will learn a lot about the cam with that info.
DD

I am running the EDL-1801 carb on my Slantkota. No big mileage numbers there with a 2500 stall converter, weird cam (previous owner as well), and big flat truck body - 18 MPG.

My 27 MPG was with the 5spd EFI 64 Dart. Big cam, but more efficient car and drivetrain overall.

Lou

_________________
Home of Slant6-powered fun machines since 1988