exhaust, carbs, etc. for most power, least expense

[pflaming]

I'm close to having a driver: power train details are next. I have a standard 218 and will use a 3:55 differential, been following a dual carb thread, and conclude I will stay with a single carb so. . . recommendations for:

1) exhaust with a single pipe:

2) fan: electric? helpful?

3) fan: shroud? fishing is at 7,000':

4) Electrictronic distributor?

5) OTHER:

[MBF]

I had the local Midas shop mandrel bend me a header pipe with a single 90 degree bend. I think that cost me about $40.00, and then bought a standard type muffler from NAPA-the glasspack I had on it was too loud. On the output side I added a 15" turndown pipe. I have a 9' flatbed so I wasn't concerned about going all the way out under the body with a tailpipe. When I did my 12V conversion, I switched to a 12V coil, and left the standard ignition point setup in place. I've never seen a shroud on a PH radiator, but that doesn't mean they don't exist or couldn't be made. I'm running a 4 blade fan for many years now w/o a problem. I have a 6 blade fan hanging on the wall that I was going to try, but if it aint broke, I'm not fixin' it. Mike

Edited February 13, 2012 by MBFowler

[Dave72dt]

Will the engine be apart? Milling the block and/or head will help the compression ratio. Otherwise some time spent smoothing the insides of the exhaust ports and manifold will help. Mandrel bent exhaust tubing. I wouldn't go bigger than 2" tubing. You won't gain anything going bigger with a stock engine and it may cost you some on botttom end torque. One of the best things you can do is make sure it's tuned well. Tires need to be inflated properly ( less rolling resistance) and aligned.

[pflaming]

My engine is "complete". I did nothing to the exhaust manifold. I'm learning that getting exhaust OUT is almost as important as getting air IN. Maybe they are equal. Being a former English teacher, this field of automechanics is really fasinating. But like the English language, if you don't know the nouns and verbs there's not much sense in teaching about gerunds and participles!! So get the air flow correct and alot of other problems will be reduced or eliminated. . . is that a fair statement?

[Dave72dt]

Pretty fair. Maybe more like improving the efficiency of what you have. Compare it to driving into a head wind. It just takes more energy to maintain speed or to accelrate than it does with a tailwind. Without changing anything inside the engine to improve it's effiency, all you've got is things on the outside of it that rob from what you do have.

[Rusty O'Toole]

If you have all the parts keep it stock. If you need to buy a carb and exhaust you can get a Holley/Weber progressive 2 barrel and adapter for about the cost of a rebuilt carb.

If you get the 2 barrel carb the most economical exhaust is to use the stock manifold but have an exhaust system made up that is 1/2" larger in diameter.

The 2 barrel carb and 1/2" larger exhaust, is basically the same as the Super Six option on the Slant 6. This was an optional engine for Valiants and Darts in the 70s and early 80s, that gave 10 extra HP.

These 2 mods will free up a little more power. If you can find a 1957 or newer cylinder head it will have higher compression, or get your old head milled. I wouldn't bother with this unless you have the head off anyway.

Edited February 19, 2012 by Rusty O'Toole

[Jim Shepard]

I'm close to having a driver:

Are you going to make it to the BBQ at Tim's on April 7th?

[Don Coatney]

Biggest single bang for the buck is mill the head for increased compression. Once you have done that drive it for a while. If you want more then open the wallet and spend away.

[Boss Hog]

Can you let me know about the installation and how on the 3:55 Differential?

Thanks..

[Rusty O'Toole]

You mentioned electronic ignition, fan shrouds and electric fans.

On flathead Chrysler products the radiator is so close to the fan that a shroud would be unnecessary.

The electrical improvements would depend on having 12 volt electrics. In that case an electric fan would save you horsepower, and improve gas mileage. Would also reduce under hood noise. If you do this mod you will need a fan that goes in front of the radiator. The best junkyard source for this type fan is a GM minivan. They have a good sized fan and they are in front of the rad. German cars often use an auxiliary fan in front of the rad too.

If you do this you will need to add a temperature sensitive switch to the cooling system to turn the fan on when needed. You will also need a relay. And of course the wiring.

For electronic ignition I have had good success adding a Ford thick film ignition module. It will work with points ignition.

Or, a simpler alternative is Pertronix ignition.

Both these would be nice to have but not worth converting to 12 volts for.