Gas mileage with 4-2 intake

[Walt Dupont--Me.]

Just thought I'd mention this. I checked the gas mileage on my 40 with the 4-2 intake, 19.3 on the 100 mile trip I took last Sat. This was not turnpike, 2 lane road with a town with a few lights, not babying it, 60-65 mph most of the time. Pic of the car and engine in down below this page may be on page 2 now, it down at the bottom of the thread where they are talking about 4-2 intakes. The engine is a 276, hot track cam, milled heads with almost 10-1 compression, T-5 trans, 9in. rear with 3:50 gears. Uncle Max setup the four 97's with the right jets and power valves, I pulled a couple of plugs when I got home, they we white, BTW it's set up for direct linkage, not progressive. Cain't kick with that. Walt

[Richard in Florida]

Originally Posted by Walt Dupont--Me.

T-5 trans, 3:50 gears.

WOW! Attaboy, Walt. Do you mean 3.50 or 3.54? What's your 5th gear ratio?

[Jack 34pu]

WOW! I'm getting about 10-11 mpg around town and 15 on the road. Stromberg 48 on 221ci w/ 4:11 rear. "I'll give you a hunert bucks fur yours!!" Ha! You fellows with the experience can sure bring out the best in these old flatheads. Keep us posted on any new "tricks of the trade".

[38 coupe]

And there is the value of tall gearing. The 3.5 axle plus the overdrive 5th will really drop the rpm. That plus high compression and good jetting = decent milage.

I have a friend with a stock 50 4 door, fresh rebuilt engine, 0.7 overdrive, and 3.73 axle. Cruising 55-60 mph he gets 23+ miles per gallon!

[Walt Dupont--Me.]

Originally Posted by Richard in Florida

WOW! Attaboy, Walt. Do you mean 3.50 or 3.54? What's your 5th gear ratio?

Richard, I installed that S-10 T-5 and the Bronco 9in. rear 10 yr's ago, I'm pretty sure it's 3.50, I don't know what the 5th ratio is with the OD and 3.50 rear. I do know that at 60 mph with a GPS I'm turning 2000 rpm. You couldn't run that high of a ratio with a stock engine. I have alot of HP but on a long upgrade I have to kick it back into 4th. Walt

[flatjack9]

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I've got a 3.70 ratio and with my Ford top loader OD, I'm turning 2000 rpm at 60 mph with 225-75R15 rear wheels.

[Vergil]

Walt that is great mileage, love the 4X2 setup, thanks for the update.

Vergil

[Ol' Ron]

Great job walt, I think the forums have contributed to the advanvement of oue old flathead by bringing together the ideas of many. 40 years ago a friend of mine tried to run a 4 carb intake, but it just didn't work right, fast idle, bucking at low speed, just a bummer to drive. One thing we didn't have was Uncle Max. One of our problems is the choice of camshafts. In JWL's book "Flathead Facts" the Max#1 cam lost 10 ft/lbs of torque at 2000 rpm. Imagin how much you might loose with an L-100 or 400jr or any other long duration cam. The stock cam is a much better choice if you mlan on running a nurmericaly lower gear. The Max#1 cam produces 10 ft/lbs more than the stock cam at 2500. Ignition curves also play an important pat in fuel economy.

[3blapcam]

I love this kind of data!

Here's a link to an extensive article on the T5:

http://www.flatheadv8.org/ernie/ernie-t5.htm

Summarized: S10 OD's range from 0.86-0.72
But, there are OD's as low as 0.63!

3blap.

[Walt Dupont--Me.]

Originally Posted by Ol' Ron

Great job walt, I think the forums have contributed to the advanvement of oue old flathead by bringing together the ideas of many. 40 years ago a friend of mine tried to run a 4 carb intake, but it just didn't work right, fast idle, bucking at low speed, just a bummer to drive. One thing we didn't have was Uncle Max. One of our problems is the choice of camshafts. In JWL's book "Flathead Facts" the Max#1 cam lost 10 ft/lbs of torque at 2000 rpm. Imagin how much you might loose with an L-100 or 400jr or any other long duration cam. The stock cam is a much better choice if you mlan on running a nurmericaly lower gear. The Max#1 cam produces 10 ft/lbs more than the stock cam at 2500. Ignition curves also play an important pat in fuel economy.

Your right OL,Ron, I couldn't have done it with out Uncle Max setting up the carbs with the right jets and power valve for direct linkage. I never ran 97's before, always used 94's, I would have never known what jets an PV to put in. To me the 94's are alot simpler, I have 3 on my dragster and she comes off the smooth as a smelt. Your right about ideling a little fast, it don't take much air leakage around 8 butterflys for it to idel a little faster than you would like, I set the carb up with a U-Syc so there all 4 perfect. Walt

[Ol' Ron]

Keep putzin, you'll get it.

[HotRodmicky]

So which jets and PVs did you use?
Michael