Squeaking out a little more performance

[Billschroeder5842]

Yes, I am an optimist....

Is there any tricks that any of you have tried to squeak out a little more performance from our late 70"s machines?

Mine is a 75, 400 4bbl with dual exhaust, Canadian build. It is very stock---even the emissions junk works.

I know that cams, headers, intakes... yada yada will make a difference- been there and done that. I'm interested in little tweaks that you all have done to pull a little here and there while keeping things basically the way things are.

Anything?

 

[Photon440]

Quickest fix that won't disturb the "underhood stockness" would be some 3.55 rear gears...unless you already have the 3.21 and then it wouldn't be worth the change.

 

[roadrunnerron]

I took away somewhere near 100 lb of bumper weight by cutting away most of the U beams. This will weaken the bumper, but my Doba will still cave in most cars on the street.

 

[HEMI-ITIS]

A little wiff of nitrous:naka:

 

[Darter6]

Some minor upgrades while looking factory stock. The intake, remove carb, you will see the fittings inside the intake for the EGR that stick up disrupting airflow.They can be removed and replaced with flush pipe plugs. Remove the heat riser valve on the passenger side exhaust. is your car equipt with a cold air tube from air filter to innerfender for fresh unheated air ? If not you can install a set up from a 79 B body.Not many will know that it didn't come that way. Little things to try.

 

[1778ppr]

Tricks for any car. For a drag car: Assuming it is a street car and in good tune to begin with and working with what you already have.

Lighten as much as possible, (Take as much out of the car as you can.) spare tire, jack, washer fluid, ½ tank of gas, tools, misc. stuff. It all adds up. They say every 100 pounds removed equals 0.100 seconds off your ET.

Flip the air cleaner cover to allow more air through the air cleaner while keeping the air cleaner on. Some would say remove your air cleaner all together to increase CFM.

Richen your carb up some

Advance your timing

Raise the front tire pressure and lower the rear tire pressure a couple of pounds

Keep the intake (induction system) as cool as possible (ice) keep the hood up as much as possible

Windows up and keep everything turned off while making a run so that the alternator is not trying to charge the battery as much. The only drain on the battery and therefore load on the alternator should be from the ignition system.

Removing the belt(s) to make “a run” can make a noticeable difference in the ET depending on the car. Not driving a fan, water pump, alternator, power steering pump, ac compressor, etc. makes a difference.

Darter6 makes some excellent car specific points. I did that on my 400 and blocked the heat cross over with the "race" intake gasket. I really only drive my car in good weather any way.

 

[PoppaSmurf]

if your running the stock ignition box, change to the Hipo(orange box), a little larger spark plug wire 8.0 Taylors , Accel, Mallory, and you can get them in black, up grade your coil(40K volts or better), as stated turn your breather cap upside down, richen up your carb a little you'll have about 2 inches of exposed air filter showing, bump a little timing with 93octane...should notice a difference

 

[Darter6]

I've only owned my 79 300 for 2 years but that thing must have over 100 lbs of thick tar paper insulation sound deadener in the trunk alone.I haven't pulled up the rugs to see if the same is underneath. I have no idea if Dodge or Plymouth used this much sound insulation.

 

[Mr75Runner]

Greetings, fellow 75 Runner-man!!

Tweaks: Carb and ignition.

On a money-for performance basis without changing major engine parts, I've always gotten the biggest snap from re-visiting the basics. Carbs and ignition seem to get old and tired slowly, sneaking up on us, and only when we work on it, do we know how much.

How's your carburetor? Still have the factory ThermoQuad? A rebuild may put some snap back....especially a professional rebuild. (I've done my own, and I've paid to have it done.) If it's fresh, you might consider switching the jets and metering rods, to richen-up the power curve. Cheap and easy....if you have a guy in the area who knows what he's doing, and who has a dyno, that's the best way. Or, you could just bump it up 2 steps. Easy to do with Carter carbs.

Ignition -- orange box? How is your distributor's health? That's a big one: I've found that just replacing the vacuum advance unit on the distributor makes it run like new.
You "might" want to consider hiding an MSD installation....MSD and hotter coil. That would help, too.

BTW: I truly love the color of your bird. "Deep Sherwood Green Metallic".....my favorite color!! You're very fortunate to have the rare 400 in her. Isn't this the 75 that Herb's Parts had for sale a while back?

 

[droptop]

Bill, I used 906 heads, intake and exhaust manifolds, cam, and carb from a '69 383. It woke up my 400, and still looks close to stock to the untrained eye.