cheap heads-free 340 heads on a 360

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justthatguy

justthatguy

Josh(69 Valiant)
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I have a set of 340 heads floating around one of the many barns here that are still in the plastic and have never been opened(bought from chrysler many years ago). After years of posting here, I finally have secured a drag car to race this coming summer. It has a 360 with a Stealth intake, 750 double pumper, a huge cam(not sure what, was my dad's build years ago), hooker headers(that will be unhooked from exhaust to race). I believe its a smog motor though, running stock compression. Question is, assuming these are j castings(can't actually remember what they are), is there any benefit to putting them on the engine or is it just a waste of time?
 
340 and 360 heads were all very similar. The 2.02 valve versions can flow more but really won't be a benefit over 1.88" valves unless it's more modified, higher rpm combo. If the heads you mentioned are NOS, you will have nice, high valve seats which will flow better over a set of heads that have had a few valve jobs. But I would save them for a better build or sell them to someone looking for a set of NOS heads for a restoration.

I am curious about the casting numbers.

"Huge cam" with stock compression is not a good combo as it will hurt power overall.
 
depends on the valve sizing of both heads
if the heads on the car right now are 2.02 exhaust then I wouldn't even touch them
if the heads on the shelve are the smaller ones (what is it, 1.60?) then I wouldn't even touch them

even if the ones on the shelve are the larger ones you should consider what work might have been done to the heads that are on the car right now
if the heads are ported, blended, maybe even milled down a bit then there is a good chance you will loose power by swapping
 
I don't believe anything was done to the motor other than the cam. I don't think any of the internals were ever touched.
 
Doesn't it have to have heads to run?
 
Then you will basically change nothing.
 
I'll race it this season and maybe the next but if I have my way it won't be 360 OR auto for long. Thanks everyone. It may be slow for the noise it makes but it beats a Fox body.
 
There are MANY more ways to make a car fast besides the engine. Once you get it super tuned just right, move on to the rest of the car. It's the car that's most important anyway.
 
RustyRatRod said:
There are MANY more ways to make a car fast besides the engine. Once you get it super tuned just right, move on to the rest of the car. It's the car that's most important anyway.
Click to expand...

:thumbup: Agreed. No sense in adding a lot more horsepower if you can't get it to the ground efficiently. (i.e.: drivetrain and suspension, but also consider frame connectors) Otherwise, you'll be literally spinning your wheels!
 
RustyRatRod said:
There are MANY more ways to make a car fast besides the engine. Once you get it super tuned just right, move on to the rest of the car. It's the car that's most important anyway.
Click to expand...

No kidding about making it fast...the engine is only about 1/4 of making a car "fast"...nothing like seeing a guy at the track with a car you just know makes over 450 hp only pulling a high 13 because it's not geared correctly or can't get traction.
 
Probably 15s as is, maybe 16s. The Suspension is pretty well set up for the amount of power it has, though.
 
Whenever I tried to get cheap head, my GF got mad at me.....
 
Whenever I tried to get cheap head, my GF got mad at me.....
Click to expand...

Nice ;)

I'm with locomotion on this one, a big cam will kill a smogged 360's powerband, unless you build the rest of the car to deal with the soft lower end. If you're rocking a stock 360, match the cam to the stock compression, induction, and exhaust then put your money into a good converter, and set up your tires/gearing to how you want it to run...be it for 1/4 mile or around town driving...there's trade-offs in every decision, but a good converter will benefit you in either case.
 
Converter is definitely first on the list. And I just wanted to see if I could get any sort of budget build out of what I had.
 
The 360 in my 73 Duster has the stock bottom end with J heads that have 1.88 valves. I did some minor porting to the heads to gasket match and clean up the runners. It has a Edelbrock RPM Airgap inake with a Holley 750. Comp cams XE268H cam and springs. Heddman block hugger headders with 2-1/4" dual exhaust. I didn't dyno it because it was just a throw together motor but it goes like a cat with it tail on fire. The car is a 4speed with 3.23 sure grip.I raced a 68 GTX 440 4 speed that was running 425hp and by the time I shifted into 3rd I was a car link ahead of him.
 
If you have a big lift cam in it someone probably cut the heads for
Spring bind, was this engine ever run or turned over ?
 
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