Should I port my j heads?
 

Got a 340 with stock J heads should I port them or buy aluminum heads? I can't really find the specs on these things

How much rpm do you wish to run to.
How much power do you wish to accomplish.
Most every decision depends on budget and end result required.
Aluminum heads will be less expensive than an all-out/Super Stock type porting job.

Rebuilding the stock heads with a good grind, valves, springs, keepers, retainers, and assembly could run you up to the comparable cost of aluminum heads. And you still have old iron heads!

what are the flow numbers of stock iron heads, I see aluminum heads are about 66-67cc and about 170cfm trying to compare that to the iron heads. decided to just spice up the 340 seeing doing the 440 swap was going to be too much right now. maybe down the line Ill find a gutted car and throw that in but for now its just gonna sit the garage lol

Totally agree with what Drag says. Here are some numbers and some pretty pictures.

http://www.shadydellspeedshop.com/moparheads.htm

Just looking for more hp than stock read they only have like 300hp lol

Stock 340, assembled correctly with the correct, timing curve, jetting, accelerator pump adjustment, 10" converter, headers and nice exhaust, 3.91:1 gears and it's an easy 12.90 - 13.0 car.

Depending on the weight of the vehicle, correct? Or does that not factor in as much?

I've got a friend with a 69 Dart GT 340, it's stock but has the old Hemi grind DC cam, headers and a converter, 12.70s.

so called a few local spots to see how much porting will cost they will port heads and intake, and open valves from 1.88 to 2.02 for 500 bucks. seen some port work they have done and looks great. I will definitely be going this route. don't really care about an extra 50lbs.. nothing nitrous cant fix lol.

Check with your builder ! Nitrous may make a difference in the valves he installes

Buy a set of aluminum heads. You'll get better flow and power.

Guys -
OLD thread.

Having gone through this with Edelbrock, Trick Flow, Mancini Racing and a few others, the consensus was that a decently ported set of cast heads will not, repeat, NOT suffer when compared to off the shelf aluminum heads in street applications.

Porting aluminum heads or using legit race cams and things might change.
Remember, dyno readings are (usually) reported only for max torque and HP, not in the rpm range a street car usually lives.

As much as I'd love to throw pair of Eddy heads on my 440, I'd be doing it more for looks than performance.

Archer