68 300 upgrades from stock (cams/heads etc.)

[Will98ow]

Recently picked up a Black 1968 Chrysler 300 2 door. 350 HP 440, single exhaust, 2.76 rear gears. Semi verifiable 71k on the clock, mostly original, drove it at interstate speeds for about 4 hours after buying it.

Looking to do some modifications to it to increase power and get it to spin the tires. Planned dual exhaust, headers, tune up, and a gear swap to 3.23s as I don’t care for the 2.76 gear set with the factory tire size. Potentially a timing chain/head/cam swap. I cruise around 70 where I live, lower elevation, and have access to higher octane fuel if it matters much in my case. Weighs 4540 with me in it with a half tank. What combos are you guys running for your comparable c bodies or slab side mopars?

 

[413]

Good plan on the gears. Headers and dual exhaust won't help it spin the tires. Gears and timing will help that.
A 68 440 350 horse is a great engine.

Absolute first thing is dump that 2.76 for 3.23.
Now check out all the tune up parts. Are the plugs old and fouled? How are the plug wires?
Does it have 91 octane or more? If it has regular run that out of there.
Does it ping at wot? Advance timing till it does, then back off 4 degrees. The pinging will change with the gear swap

What carb is on there? Is the choke adjusted right?

 

[Will98ow]

Good plan on the gears. Headers and dual exhaust won't help it spin the tires. Gears and timing will help that.
A 68 440 350 horse is a great engine.

Absolute first thing is dump that 2.76 for 3.23.
Now check out all the tune up parts. Are the plugs old and fouled? How are the plug wires?
Does it have 91 octane or more? If it has regular run that out of there.
Does it ping at wot? Advance timing till it does, then back off 4 degrees. The pinging will change with the gear swap

What carb is on there? Is the choke adjusted right?

Thanks for replying! It has the original 4 barrel carter AFB or AVS. Going to be going through it, or perhaps throwing a spare edelbrock I have on it. It is rich in the secondary’s. I plan on doing a full tune up for the easier things (points,plugs,wires,carb etc.)

No pinging at wide open throttle, ran a timing light on it immediately after buying, it was about 4 degrees shy of whatever the manual I had said it should be, so I advanced it. I use 91 octane ethanol free or better, I have access to 110 leaded that I use for my other vehicles.

 

[413]

That stock carb will be better than an edeldork.

Get the number off the front passenger corner of the base of the carb.

Advance the timing more.

It will be a different car just swapping the gears so do that ASAP.

 

[Boydsdodge]

Every engine wants a different initial timing, total timing is a mostly at 34/36 deg mechanical. Lighter springs in the distributor will help as well. Gears and dual exhaust is good for seat of the pants feel.

 

[Will98ow]

Every engine wants a different initial timing, total timing is a mostly at 34/36 deg mechanical. Lighter springs in the distributor will help as well. Gears and dual exhaust is good for seat of the pants feel.

Thanks. Any cam recommendations? I’ll eventually be that deep into it. Also looking to add 440 source aluminum heads. No comp cams, or lunati though. Had parts fail from those manufacturers.

 

[Boydsdodge]

You want a cam the works right away from idle to 4500 rpm
big torque with wide curve.
For finding your timing you will need a dial back timing light and a vacuum gauge with test drives. Then you need to recurve your distributor with what info you found and the total the engine is good with.
Do a compression test first.
One of these comes in handy.
Tall John is a good source.

 

[MEV]

Before you do anything, put as much timing in it as it will take, when my 66 newyorker was stock with its 440, with 2:76 gears, it would burn tires for days, completely stock.

 

[bronze turbine]

I agree with that last post, you should be able to break the tires loose with everything stock if it's all working right. Dual exhaust is nice, but I think headers is overkill. Changing the rear gear will give you a lot of bang for the buck, but don't overdo it if you still want to be able to cruise the interstates in comfort. I have a 3.23 in my 300 I wouldn't want any more.

 

[413]

Before you do anything, put as much timing in it as it will take, when my 66 newyorker was stock with its 440, with 2:76 gears, it would burn tires for days, completely stock.

A 1966 440 has closed chamber heads and small exhaust valves. That equals better throttle response and bottom end power than a 68 engine.

 

[sunmountain]

Nice ride! def go for the 3.23 gears, should wake it up a bit.

 

[CBODY67]

Before you do anything, put as much timing in it as it will take, when my 66 newyorker was stock with its 440, with 2:76 gears, it would burn tires for days, completely stock.

Even our '66 Newport with 383 2bbl and 2.76 tires would lay rubber. Back then I was not into "giant smoky burnouts", just some patches at it did that completely stock. Stock initial timing was 12.5* and I ran it at 15* for just a bit more. Add two full turns to the kickdown rod preload for a tad higher part-thorttle shift points and a better driving feel.

If your 440 needs to be on dirt to spin the tires, it needs some driving to get the accumulated carbon out of the combustion chambers AND some fine-tuning, to me.

CBODY67

 

[Big_John]

Recently picked up a Black 1968 Chrysler 300 2 door. 350 HP 440, single exhaust, 2.76 rear gears. Semi verifiable 71k on the clock, mostly original, drove it at interstate speeds for about 4 hours after buying it.

Looking to do some modifications to it to increase power and get it to spin the tires. Planned dual exhaust, headers, tune up, and a gear swap to 3.23s as I don’t care for the 2.76 gear set with the factory tire size. Potentially a timing chain/head/cam swap. I cruise around 70 where I live, lower elevation, and have access to higher octane fuel if it matters much in my case. Weighs 4540 with me in it with a half tank. What combos are you guys running for your comparable c bodies or slab side mopars?

My tire burning days are long gone... That said, when it comes to the 440, often less is more.

The dual exhaust and 3.23 gears will help. TTI makes a nice dual setup. Instead of headers, think about finding a set of HP manifolds. You want to take advantage of the 440's low end torque and IMHO, the manifolds will help that more than headers without a lot of loss of top end, plus being a lot less of a pain in the butt.

 

[496 polara]

If I were going to waste money on HP manifolds I would just put it towards headers. Either the Schumacher tri y or the Hooker Super comps with a 1 3/4 primary tubes.

A good 2.5 dual exhaust off the current manifolds will be plenty. 2.25 tail pipes won't hurt a thing either. A factory high stall converter (like specs for a 383 road runner) will help as well.

I agree with the 3.23 gears and a suregrip.

Nothing wrong with the factory cam in this application IMO and no worries of wiping a flat tappet.

For a power upgrade a set of stealth heads or the like painted to look stock would likely give all you wanted and leave some folks scratching their heads at how well it runs.

 

[Will98ow]

Even our '66 Newport with 383 2bbl and 2.76 tires would lay rubber. Back then I was not into "giant smoky burnouts", just some patches at it did that completely stock. Stock initial timing was 12.5* and I ran it at 15* for just a bit more. Add two full turns to the kickdown rod preload for a tad higher part-thorttle shift points and a better driving feel.

If your 440 needs to be on dirt to spin the tires, it needs some driving to get the accumulated carbon out of the combustion chambers AND some fine-tuning, to me.

CBODY67

Definitely something for me to try. I did notice after about 2 hours of continuous driving, it was running noticeably better if only at highway speeds so that coincides well with what you stated.

 

[Will98ow]

I agree with that last post, you should be able to break the tires loose with everything stock if it's all working right. Dual exhaust is nice, but I think headers is overkill. Changing the rear gear will give you a lot of bang for the buck, but don't overdo it if you still want to be able to cruise the interstates in comfort. I have a 3.23 in my 300 I wouldn't want any more.

3.23s would be all about I could manage without an overdrive unit at highway speeds. I have a 78 Aspen RT with a good 360 and 3.55s, it’s a bit buzzy past 60 (way smaller tires than the 68 300 has.)