Hello all. Building out my '63 225, and I'm curious: is there a thread already on here devoted to engine rebuilds and what combinations yield what results?

If anyone has a good setup that delivers MPG and power (without sacrificing it too much), please describe some of the specifics. Thanks!

For starters go to;

Forum Index>Engine>Frequently Asked Questions>Engine Build Matrix

There's good info there including some builds for mileage plus that F.A.Q. thread has all sorts of other links to point you towards Slant Six Nirvana.

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1966 Coronet Deluxe

Where in the thread is this? I've gone through it before and have not found this build. Partly why I asked the question again.

The only changes I would look at is using a 68 - 75 cylinder head and using the Erson RV10/295 RDP cam.
Calculate the needed amount of block & head milling to get 8.0 to 8.2 DCR numbers.
DD

x2 on the 1968-1974 head (to retain the "stock 1963 drool tube look" but have the better combustion chamber)...

I would probably ask for moly rings since they keep the oil where it should be over the iron rings...I would also save on the wallet and go with new stock single springs since you aren't running a race (340 dual damper springs not needed on a small cam like that, if more spring rate needed a set of 318 springs would do it).

After Engine break in has occured, I think a custom distributor recurve would help and recalibrating the carb a bit would go far as well (Ted uses a Holley 1920 Economaster, the Feather Duster/Dart Lite program was a Holley 1945 only).

-D.Idiot

Thanks DI, it would be nice to change that typo some how.....

This is a good start but not all of the story. You have to be willing to make a few more changes to tune the engine and make it function better.

To answer your question directly, my average local driving mileage was 18 mpg. After the rebuild it went to an average of 22+ mpg.
I have a very heavy car 3380 lbs with a full tank, 3600 lbs with me in it. Book specs show up to 3180 lbs. in 1974. Your car is much lighter so mileage improvements would be better.

So you may be thinking how did I go from an average 22 mpg to over 25 mpg?
After many discussions with "Doc" Doug Dutra, he convinced me to forget about horsepower and work on fine tuning and building torque.
My rear end ratio is 2.76, a 489 case with a Sure-Grip, 8 3/4 rear end. I tore up (4) 7.25" rear ends on my daily commutes, 130 mpg a day over about a 5 years. I run 26" tall tires, P215 -70R 14" tires. So torque is a must with a heavy car and high gear ratio.

Doc felt the 1920 Holley Economaster R7585, was a great base line. It has the wagon wheel style venturi for excellent air/fuel mixing. For reference: most stock 1920's are not designed this way. The 9.5 compression ratio is one of the biggest hits on developing more torque. Also longer valve seat time by running .012 and .022 helps mileage. One thing you see Doc mentioning a lot is a free flowing exhaust. I have tested many onfigurations and I really like running 2.5" pipe all the way but, you create more noise, so I run a 18" FM HP2 dual cone muffler up front into a FM 70 in the stock location. This system is super quiet and a pleasure on trips and is very free flowing. I drive with a vacuum gauge and from 2200 to 2500 rpm the engine has massive amounts of power and excellent vacuum, 16" to 22".

Ok, key things to do improve mileage.....after the engine rebuild
1. #56 jet in the Economaster. Rebuild every 5 years do to the ethanol in the gas. Very spunky set up.
2. Dual 10" electric fans. They rarely ever come on and reduce engine drag, and improve intake manifold heating.
3. Heat shield so the intake warms up quicker and keeps the carb cooler, no carb heat soak.
4. Air dam under the car for improve air flow into the radiator.
5. Distributor recurve, this is a big one. I really enjoyed that project. Big mileage improvement and it makes the torque hit very hard.
6. Cold air intake for the carb.
7. Aluminum single barrel intake. This intake is awesome.....warms up very quick for great atomization over a cast iron intake. This plus the intake heat shield are a must. I making a new one which is a little thicker and much bigger so it covers the entire intake.
8. Hotter spark, Pertronix 60,000 volt 3 ohm coil, no ballast resistor, and 8mm wires and MO-3000 rotor with .045 spark plug gap.
9. Mobile 1 Synthetic oil
10. SL6Dan's fuel line mod.

These improvements helped me get to 25+ mpg. My body style is very boxy, 74 Swinger. Doc said to drop the nose a little and that would help. So I have about a 2.5" rake with the new rear 6 leaf springs, plus the air dam. A Duster body style will get much better mileage up to 30 MPG. I have been in the car that got that mileage. It had a 4 speed and overdrive and a crappy Holley 1945 like my car came with.....I could never get over 24 mpg with that carb.

Hopefully my experiences will help you. As you see it is a combination of improvements to keep the engine happy and running at peak efficiency.
Click on the red link below my name to view some pictures of changes over the years.

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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

Thanks for the details, AT, Doc, and DI.

AT - was looking over your Swinger pics. Nice work you've done there. A clean engine compartment too: what a beautiful thing compared to my current greasy mess. Looking forward to getting my rebuild done with new gaskets, seals, and everything that will aid me keeping my engine compartment clean. Had it steam cleaned a year ago, and you'd never know it. Guess that illustrates how leaky it's gotten.

Was looking over the modifications you've done to improve mileage. I'm definitely on board with getting significantly more mpgs. Above 25+ would be fantastic for this car, and you're right, it is far lighter (not exactly sure of GVW) than the Swinger. Had your exact same Swinger myself (below), car was completely stock original, but the 225 always felt underpowered for the weight of the car and didn't have nearly enough torque.



All this said, I need to decide what I'm on board with. It make sense to upgrade for better performance because I'm going to convert the Dart wagon to my daily driver. Out of all the mods you did, which singular upgrades were the most effective? I realize they all work together but some of them that change the overall stock look of the car I may not want to do.

Wow! beautiful car.....

Your right, the stock 74 slant is a real slug that pings a lot........
It used to drive me crazy on how to tune it so it wouldn't ping on some hills. No more zero degree timing......

I would have never thought it possible but, You can turn it into a tire burner with some compression and a distributor recurve. Mine will surprise you by breaking both rear tires loose at a stop light.

My hat is off to Doc (Doug Dutra) as he has been a great teacher!

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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

WOOHOO! just what I've been looking 4!

I was going to make a new Post "Can the pertronix ignitor be considered a electronic ignition?" and if I had to Gap plugs to a different Gap. to many would say Yes and others didn't convince by saying NO.

I was having problems with my Pertronix. car running rough blah blah. turns out it was 2 dead cylinders from valves being too tight. I did SSDan's fuel modification using a glass filter. I've always used them in my other cars, haven't had one break yet "JINX"

Call me Rebellious...
Thanx Agreesive TED