360 upgrade

[aceofspades]

... because if it doesn't sell, I want it to run like hell.

'79 Chrysler 300. If memory serves the stock 360 has 8:1 compression. I've heard about ditching the quad/emissions/etc.

These came from the factory with 195 horses. How could I double that?

Performance heads, headers, carb and a slightly bigger cam?

What say you gear heads?

 

[Darter6]

The factory 195 hp was way underrated, it was a net scale and not gross rating.Gross would be near 300 hp.There are things that can be done with little effort. The first is a very restrictive exhaust.If you have no problems with the lean burn I would leave it for now.Mine would not start hot so I ditched the lean burn for Mopars regular electronic ignition.I also don't have to deal with smog regulations so all of that is removed.These 300 came with a 3.21 rear gear so it is good for street use.I Would start there along with a good tune.My 300 will fry the tires at ease.

 

[aceofspades]

I did hear they were under rated. My new exhaust I had put on was pipes with glass packs and bent the same as the factory pipes.

The only problem with the Thermo is a hesitant spot when the accelerator is halfway down. I've been told the accelerator pump could be it. I also here the Thermo is badass when properly tuned. Also, if I jam the pedal from a dead stop it just cuts out.

 

[Darter6]

I would say the carb needs gone thru. But look to see if you are getting a good squirt from the accelerator pump. If good ,,increase the timing till the bog is gone.yes Thermoquads are a great carb when set up properly.

 

[moper]

As was said - net rated at 195, it's closer to 250 gross in factory form. Still not a barnstormer but fun.
1. Replace the manifolds with headers and a good flowing dual system (2 1/4 or 2 1/2 pies are fine - hi flow cats if you have to run them).
2. Rebuild the Thermoquad. They are hands down the best factory carb. If your's is studdering it's probably gunked up. Pay attention to float drop and float level settings too. Reset the accelerator pump linkage to the innermost hole for maximum pump volume. Add 1 turn clockwise to the metering rod hanger.
3. Remove and plug the floor jets inside the intake's plenum.
4. Replace the distributor with either an MP/Summit/stock electronic unit and set the ignition timing curve up. 16* initial, 22* centrifugal for 38* total.
Once that's done, if you want to break into it more, replace the cam with something on the order of a Crane H-260-2, a set of Comp 901-16 springs, and replace the exhaust valve rotators with std stock exhaust retainers and locks (of any non-360 LA smallblock).
You won't get 400hp without tearing into it a ways and losing the power brakes. But you can get a serious boost in torque and horsepower - clearing 300 gross is easy enough.

 

[aceofspades]

Thanks for the advice. Good summer project if it doesn't sell by then.

 

[rumblefish360]

What Moper said and .....

What year TQ do you have and are you running the Lean Burn set up.
(Both need to be dumped.)
An older TQ with the large primary's and a good distributor!

On headers, use ether the Hooker "Super Comps" (@1-3/4) or the full tti system. I would certainly go with a 2-1/2 pipe!

A small cam would be a good addition. Keep it small. Under 220 @ .050.

What gears & tire size are you running?

 

[aceofspades]

It's the original TQ, 1979. Already has a mild cam straight from the factory but not sure of the specs. Has the original 3:23 rear and has 15" tires on the original wheels.

 

[aceofspades]

Honestly I just wish I could sell it. I really need a truck. I can always have a cool sleeper truck and haul stuff when I need to.

 

[rumblefish360]

Well, if you own the car outright, classic insurance is cheap, so actually owning the car is just insurance, plates and inspection? I don't know your laws but those would be it for me.

On the carb, an earlier model with a vacuum advance port is needed for use with a (of course) vacuum advance distributor. This will open up a good few ponies for sure.

Upgrade the ignition to at least a Chrome box or a FBO or MSD.
You can not possibly run 15 inch tires.
I asked you what tire size you have on the car. You told me a 15 inch tire on OE wheels. That is impossible. Go read the tires side wall for tire specs. (225/70/15 or something like that.

 

[aceofspades]

I know what you meant lol.

225/70 R15 on original 15X6 factory wheels.

 

[aceofspades]

Build sheet

 

[rumblefish360]

LMAO! Cool!

OK, for a cam, I'd recommend nothing larger than a [email protected] with those gears and tires. You could get away with more cam if you added more stall to the converter.
An example would be like the Purple 340 performance replacement cam, a XE268H from comp cams, etc....