Today, dollar for dollar, is the 318 faster than the 340 ???

would you agree ?

  • yep, the 318 wins if buying and building for under 3k

    Votes: 48 41.7%

  • Nope, the 340 always has and always will beat the 318

    Votes: 57 49.6%

  • Actually, never thought about it like this... Good Point !

    Votes: 10 8.7%
  • Total voters
    115
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66fs said:
The "Throw Away 318"
Click to expand...
this bit?
Below, excerpted from an article that originally appeared in Hot Rod Magazine, are the dyno results from a baseline test of a stock 318 engine, and the horsepower gains recorded after various modifications.

  • 186 HP at 4000 RPM (Base Platform):
    • 318 non-roller 8:1 compression cop car short block
    • Production 318 cam with 240* adv. dur. .390"/.400" lift
    • Heads were the 4323302 casting (302s) high swirl mileage/emissions heads with the heart shaped chamber (9.0:1 compression installed)
    • 4BBL cast iron cop car intake manifold
    • Thermoquad carburetor
    • Stock exhaust manifolds
    • Factory stock (non lean burn) electronic ignition system
  • 217 HP at 4200 RPM:
    • Added a 360 2BBL cam (252* adv. dur. .410" lift)
    • Mopar Performance Electronic Ignition conversion kit
    • Cam and MP Electronic Ignition swap was good for a 31 HP increase.
  • 225 HP at 4500 RPM:
    • Added stock 1.88" intake/1.60" exhaust 360 heads with stock springs, retainers and keepers
    • Gave the heads a performance valve job
    • Head swap was only good for an 8 HP increase.
    • Power was weaker than the swirl head combo below 3500 RPM.
  • 251 HP at 5000 RPM:
    • Added Mopar Performance P4120249 valve springs to the 360 heads
    • Added Mopar Performance P4286669 cam (260* adv. dur. .430" lift)
    • Holley 0-3310 750CFM vacuum secondary carburetor
    • Edelbrock 2176 Performer aluminum intake manifold
    • Mopar Performance P4286437 headers (1 5/8" primary tubes with 3" collectors)
    • The above items added 26 HP.
  • 290 HP at 5250 RPM:
    • Ported and polished the heads
    • Upgraded heads to 2.02" intake and 1.60" exhaust valves
    • Added Mopar Performance P4452033 chrome-moly valve spring retainers with 8* keeper grooves
    • Mopar Performance P4120620 8* hardened valve stem locks
    • Added Mopar Performance P4286671cam (272* adv. dur. .455" lift)
    • Mopar P4120600 Gold Box competition ignition control unit
    • This combo added 39 HP
  • 331 HP at 5750 RPM:
    • Swapped the 360 heads for ported and polished 302 heads modified with 1.88" intake/1.60" exhaust valves
    • Mopar Performance P4120249 valve springs
    • This combo produced a 41 HP increase over the previous combination, netting 1.12 HP per cubic inch!
    • This combo also produced more power than all of the other combinations from the lowest RPM on up

Notes:

  • All tests were conducted on an engine dyno stand with an unrestricted exhaust system.
  • 4323302 casting heads (302s), 4343646 castings and similar castings are 1.78" intake/1.50" exhaust high swirl mileage/emissions heads that were used on all civilian duty M-bodies from late-1985 to 1989.
  • Actual cop car engine compression per the 1987 Factory Service Manual was 8.4:1 due to the open-chambered 360 heads. Compression for civilian model 318s with closed-chambered factory 302 heads was 9.0:1.
  • The base HP for civilian model 2BBL 318s was about 140, so expect HP numbers a bit less than the above baseline test if you add a 4BBL intake/carburetor and convert to electronic ignition.
  • Modifications usually work together to produce results. The 41 HP increase recorded in the last dyno test was achieved because the camshaft was much stouter than a production cam, and it was designed to take advantage of superior breathing heads. A similar increase should not be expected with the same heads and a stock cam.
 
mygasser said:
so, if you found a running 340 for $1500 and added those heads it's be pretty darn good for $3000 :thumbsup:
Click to expand...
Yeah that would kill the budget through. Can we use the "spare parts laying around? I have two eddy aluminum intakes...(something tells me "no"on the spare parts ) but still, theres wight savings with just the heads I suppose.
 
Dartswinger70 said:
.........I also seem to recall UTG and Lunar Outlaws 318 only pulling 230 or something so all UT's grinding and porting on the heads did nothing for that engine in terms of HP ...............................
Click to expand...

That was the most STUPID Youtube Vid I ever saw. First pull, Nick should have just yanked that PUKE off the dyno and dumped it in the scrap bin.

Can't ever get that time back, ;)
 
mygasser said:
this bit?
Below, excerpted from an article that originally appeared in Hot Rod Magazine, are the dyno results from a baseline test of a stock 318 engine, and the horsepower gains recorded after various modifications.

  • 186 HP at 4000 RPM (Base Platform):
    • 318 non-roller 8:1 compression cop car short block
    • Production 318 cam with 240* adv. dur. .390"/.400" lift
    • Heads were the 4323302 casting (302s) high swirl mileage/emissions heads with the heart shaped chamber (9.0:1 compression installed)
    • 4BBL cast iron cop car intake manifold
    • Thermoquad carburetor
    • Stock exhaust manifolds
    • Factory stock (non lean burn) electronic ignition system
  • 217 HP at 4200 RPM:
    • Added a 360 2BBL cam (252* adv. dur. .410" lift)
    • Mopar Performance Electronic Ignition conversion kit
    • Cam and MP Electronic Ignition swap was good for a 31 HP increase.
  • 225 HP at 4500 RPM:
    • Added stock 1.88" intake/1.60" exhaust 360 heads with stock springs, retainers and keepers
    • Gave the heads a performance valve job
    • Head swap was only good for an 8 HP increase.
    • Power was weaker than the swirl head combo below 3500 RPM.
  • 251 HP at 5000 RPM:
    • Added Mopar Performance P4120249 valve springs to the 360 heads
    • Added Mopar Performance P4286669 cam (260* adv. dur. .430" lift)
    • Holley 0-3310 750CFM vacuum secondary carburetor
    • Edelbrock 2176 Performer aluminum intake manifold
    • Mopar Performance P4286437 headers (1 5/8" primary tubes with 3" collectors)
    • The above items added 26 HP.
  • 290 HP at 5250 RPM:
    • Ported and polished the heads
    • Upgraded heads to 2.02" intake and 1.60" exhaust valves
    • Added Mopar Performance P4452033 chrome-moly valve spring retainers with 8* keeper grooves
    • Mopar Performance P4120620 8* hardened valve stem locks
    • Added Mopar Performance P4286671cam (272* adv. dur. .455" lift)
    • Mopar P4120600 Gold Box competition ignition control unit
    • This combo added 39 HP
  • 331 HP at 5750 RPM:
    • Swapped the 360 heads for ported and polished 302 heads modified with 1.88" intake/1.60" exhaust valves
    • Mopar Performance P4120249 valve springs
    • This combo produced a 41 HP increase over the previous combination, netting 1.12 HP per cubic inch!
    • This combo also produced more power than all of the other combinations from the lowest RPM on up

Notes:

  • All tests were conducted on an engine dyno stand with an unrestricted exhaust system.
  • 4323302 casting heads (302s), 4343646 castings and similar castings are 1.78" intake/1.50" exhaust high swirl mileage/emissions heads that were used on all civilian duty M-bodies from late-1985 to 1989.
  • Actual cop car engine compression per the 1987 Factory Service Manual was 8.4:1 due to the open-chambered 360 heads. Compression for civilian model 318s with closed-chambered factory 302 heads was 9.0:1.
  • The base HP for civilian model 2BBL 318s was about 140, so expect HP numbers a bit less than the above baseline test if you add a 4BBL intake/carburetor and convert to electronic ignition.
  • Modifications usually work together to produce results. The 41 HP increase recorded in the last dyno test was achieved because the camshaft was much stouter than a production cam, and it was designed to take advantage of superior breathing heads. A similar increase should not be expected with the same heads and a stock cam.
Click to expand...
Nice recipies. I see they didn't bump compression with pistons. Heads and cam make sense. I see they went from 2.02s down to 1.88s? I seem to think that that makes sense. I have heard that 1.88 J heads will flow real nice on a 340. It's an almost unnoticeable difference, but opinions vary. I believe the 340/360 head casting is superior, free breathing, opened up...I never got the "head porting on 318 heads, unless you can open the runners all the way you'll always have a bottleneck. I am talking the LA casting
 
Dave_J said:
That was the most STUPID Youtube Vid I ever saw. First pull, Nick should have just yanked that PUKE off the dyno and dumped it in the scrap bin.

Can't ever get that time back, ;)
Click to expand...
. If you recall , the truth "came out" as the vid progressed. You can go to the comments today, and UT is there "citing the lifters" as the issue...:)
 
ir3333 said:
i'm betting most 340's peak around 5200 even though they are probably shifted much higher with 4 speeds.The stock 340's rev past 6000 easily
Click to expand...
My 340 goes to 8500, the X and J heads don’t stop flowing, it’s the carb that stops, reason for the TQ. Schools in
 
My son has a 318 with Mag heads and Mag Eldy airgap, small Voodo FT cam, ProCom headers in a 68 Dart 270 with 3.90:1 8 3/4 and 325 50 22's that will pull the left tire just off the ground. He has not ran it at the track as he need a windshield.

But I have a StupidRoo XT Outback 2.5 Turbo with lots of mods and a ECU tune. It too will lift a tire on launch. Has 4.44 Posi AWD and over 400 HP
 
My factory stock, tired 318 in the '80 D150 (aka Drag Truck) will turn 6k with only headers and 4bbl added. Everything else is "tired factory stock". I shift at 5k because that's where it likes it, but it will hit 6k no problem.
 
mygasser said:
this bit?
Below, excerpted from an article that originally appeared in Hot Rod Magazine, are the dyno results from a baseline test of a stock 318 engine, and the horsepower gains recorded after various modifications.

  • 186 HP at 4000 RPM (Base Platform):
    • 318 non-roller 8:1 compression cop car short block
    • Production 318 cam with 240* adv. dur. .390"/.400" lift
    • Heads were the 4323302 casting (302s) high swirl mileage/emissions heads with the heart shaped chamber (9.0:1 compression installed)
    • 4BBL cast iron cop car intake manifold
    • Thermoquad carburetor
    • Stock exhaust manifolds
    • Factory stock (non lean burn) electronic ignition system
  • 217 HP at 4200 RPM:
    • Added a 360 2BBL cam (252* adv. dur. .410" lift)
    • Mopar Performance Electronic Ignition conversion kit
    • Cam and MP Electronic Ignition swap was good for a 31 HP increase.
  • 225 HP at 4500 RPM:
    • Added stock 1.88" intake/1.60" exhaust 360 heads with stock springs, retainers and keepers
    • Gave the heads a performance valve job
    • Head swap was only good for an 8 HP increase.
    • Power was weaker than the swirl head combo below 3500 RPM.
  • 251 HP at 5000 RPM:
    • Added Mopar Performance P4120249 valve springs to the 360 heads
    • Added Mopar Performance P4286669 cam (260* adv. dur. .430" lift)
    • Holley 0-3310 750CFM vacuum secondary carburetor
    • Edelbrock 2176 Performer aluminum intake manifold
    • Mopar Performance P4286437 headers (1 5/8" primary tubes with 3" collectors)
    • The above items added 26 HP.
  • 290 HP at 5250 RPM:
    • Ported and polished the heads
    • Upgraded heads to 2.02" intake and 1.60" exhaust valves
    • Added Mopar Performance P4452033 chrome-moly valve spring retainers with 8* keeper grooves
    • Mopar Performance P4120620 8* hardened valve stem locks
    • Added Mopar Performance P4286671cam (272* adv. dur. .455" lift)
    • Mopar P4120600 Gold Box competition ignition control unit
    • This combo added 39 HP
  • 331 HP at 5750 RPM:
    • Swapped the 360 heads for ported and polished 302 heads modified with 1.88" intake/1.60" exhaust valves
    • Mopar Performance P4120249 valve springs
    • This combo produced a 41 HP increase over the previous combination, netting 1.12 HP per cubic inch!
    • This combo also produced more power than all of the other combinations from the lowest RPM on up

Notes:

  • All tests were conducted on an engine dyno stand with an unrestricted exhaust system.
  • 4323302 casting heads (302s), 4343646 castings and similar castings are 1.78" intake/1.50" exhaust high swirl mileage/emissions heads that were used on all civilian duty M-bodies from late-1985 to 1989.
  • Actual cop car engine compression per the 1987 Factory Service Manual was 8.4:1 due to the open-chambered 360 heads. Compression for civilian model 318s with closed-chambered factory 302 heads was 9.0:1.
  • The base HP for civilian model 2BBL 318s was about 140, so expect HP numbers a bit less than the above baseline test if you add a 4BBL intake/carburetor and convert to electronic ignition.
  • Modifications usually work together to produce results. The 41 HP increase recorded in the last dyno test was achieved because the camshaft was much stouter than a production cam, and it was designed to take advantage of superior breathing heads. A similar increase should not be expected with the same heads and a stock cam.
Click to expand...

So, a Stock bore and stroke 9.0:1 Teen???
Who'da thunk 331 HP at the crank?
 
318willrun said:
If I was to build a 3k 318, I'd be expecting 375 gross hp minimum. That would be my expectation. Just for funs off the top of my head, something like this parts list:
  • Promaxx heads -1400 fully assembled
  • maybe something like the lunati 702 cam kit - 240
  • edelbrock timing set - 75
  • KB167 standard bore pistons/rings - 390
  • Full gasket kit - 70
  • used RPM intake - 200
  • If the engine ran good, I'd most likely re-use the bearings and oil pump
  • 750 carb - 450
I have change left over....... You'd be pressed to buy and build a 340 to run with my combo.....
Click to expand...
You forgot the fee for getting those pistons in the block
 
Ceedawg said:
You forgot the fee for getting those pistons in the block
Click to expand...
how much to press off a piston and press on another...??? been a while. Or do it myself Steve Dulchich style...
They are standard bore pistons.
 
Ceedawg said:
You forgot the fee for getting those pistons in the block
Click to expand...
Its been a day or 1000 but when I had a set of pressed pistons replaced on 360 rods it cost me $175 so maybe $225 now. My 360 had no bore taper so just a WD40 and Ball hone to clean up glazing. I went from stock pistons to a set of 9.5 dished and new Hasting rings.

Edit, that $175 included resizing and hone the big end. I reused the old bearings as they mic'ed OK and had no embeded crap.
 
Last edited:
Dave_J said:
Its been a day or 1000 but when I had a set of pressed pistons replaced on 360 rods it cost me $175 so maybe $225 now. My 360 had no bore taper so just a WD40 and Ball hone to clean up glazing. I went from stock pistons to a set of 9.5 dished and new Hasting rings.

Edit, that $175 included resizing and hone the big end. I reused the old bearings as they mic'ed OK and had no embeded crap.
Click to expand...
So you put a nice set of pistons in a 40 year old bore? Getting real stupid now.
 
Ceedawg said:
So you put a nice set of pistons in a 40 year old bore? Getting real stupid now.
Click to expand...
Actually, I'm not sure pistons would be necessary for the 318 to outperform the 340. To be truthful, it would gain compression just by using the 63 cc heads.
 
Ceedawg said:
So you put a nice set of pistons in a 40 year old bore? Getting real stupid now.
Click to expand...
What part of a straight, untapered and still cross hatched good bore is stupid?
It had a small carbon ridge that cleaned up with a razorblade...

Why should an over bore help? ????

Remaining stupid I guess.
School me o'l wise one.
 
Last edited:
Dave_J said:
What part of a straight, untapered and still cross hatched good bore is stupid?
It had a small carbon ridge that cleaned up with a razorblade...

Why should an over bore help? ????

Remaining stupid I guess.
School me o'l wise one.
Click to expand...
Some people overbore out of general principle. If you have a "holy grail" 340 I'd measure taper, make a decision wether you think your oil rings will seal, and save .030-,.040 over boring when you don't need it is likevsanding a quarter inch off your brake pads before putting them on...
Also, some like the 6 extra cubic inches. 030 gives ya...
 
Ceedawg said:
So you put a nice set of pistons in a 40 year old bore? Getting real stupid now.
Click to expand...

Dave_J said:
What part of a straight, untapered and still cross hatched good bore is stupid?
It had a small carbon ridge that cleaned up with a razorblade...

Why should an over bore help? ????

Remaining stupid I guess.
School me o'l wise one.
Click to expand...

The reason to pull the stock 8.4:1 pistons and replace with 9.5 dished was 1 Exhaust valve rotator failed and a valve kissed the piston at idle and we shut the engine off. Engine had not run in 5 years so we did a quick fire and in 5 minutes of idling to get to temperature it went THUNK and we killed it. Valve was wasted and the guide was bad too.

We bore gauged the block and found it well in spec. We then mic'ed each piston and the small diameter ones went into the A bore's and the fatter pistons went in to the E and DD bores.

So, again, someone school this stupid foke.
 
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