Extra hp out of my 340.

hux340 said
Hi All,
I've got a 71 Dodge Demon 340. Don't know what's been done to the motor as it was rebuilt before I bought it. Seems very strong though & with maybe 10,000 miles on it. We put it on the dyno recently & it's getting 340 hp at the flywheel. I would like to get some extra hp without tearing down the motor. Has no after market mods on it besides a 670 holley street avenger. Was looking at doing the following -
1. Alloy Heads
2. Dual plane alloy intake manifold &
3. Headers (or as we call them here in Aust. extractors).
Not sure about a cam change as I don't want to sacrifice torque which it's got plenty of.
With the alloy heads I would like them to fit under the factory rocker covers. I will also paint the inlet manifold the hemi orange. Trying to keep the engine bay as original as possible.
If I do the above what hp increase would I see?
Cheers,
Glenn.

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We here also call alloy, aluminum.

Is your car an automatic trans?
What gears does the rear have and your current tire size? A cam change would need these known factors before a cam is purchased as well as IF your willing to swap a converter to a higher stall unit.

A good and properly done converter will allow a bigger sizeable cam to be used without a loss of drivability. A lack of low end torque is well covered by a good converter.

Generally speaking without much fan care or issue, a basic swap of parts is the first and easiest upgrades to do.

Holley or Edelbrock carb, Edelbrock intake and prepped Edelbrock heads make an excellent first step.

Knowing of your pistons pop up out of the block is the first BIG question as this dictates which heads to purchase. Edelbrock makes a head for this stock positive deck height piston.

The best Extractors (or headers) are ether Doug’s or tti. Expensive but OH! So very worth it.

72Dart6pack said
E3 spark plugs add a easy 20 hp. Just a thought? :poke:

LMAO... stop it all ready!!! LMAO!!!