Previous Thread
Next Thread
Print Thread
Friend Needs 1970 340 Heads - Advice? #2995574
12/15/21 05:55 PM
12/15/21 05:55 PM
Joined: Jan 2003
Posts: 8,032
Highland, MI.
Sunroofcuda Offline OP
master
Sunroofcuda  Offline OP
master

Joined: Jan 2003
Posts: 8,032
Highland, MI.
So my buddy bought a 70 Challenger 340 back in the spring & the car had a running 318 in it, but the original 340 came with it. He just found out the heads are no good. So what would be y'alls advice on what to do heads-wise? Look for a good original set, or aftermarket? If aftermarket, which heads?

Thanks for the advice.

Last edited by Sunroofcuda; 12/15/21 05:56 PM.

No Man With A Good Car Needs To Be Justified
Re: Friend Needs 1970 340 Heads - Advice? [Re: Sunroofcuda] #2995576
12/15/21 06:03 PM
12/15/21 06:03 PM
Joined: Jan 2003
Posts: 41,591
Round Lake Beach, Illinoisy
Rhinodart Online penguin-006
Rhinotruck
Rhinodart  Online Penguin-006
Rhinotruck

Joined: Jan 2003
Posts: 41,591
Round Lake Beach, Illinoisy
So why does he say the heads are no good? Are they cracked or what? Not enough info, what are his plans for the car? You can't get any better stock heads than 70 X heads! shruggy


The funny thing about science is that if you change one miniscule parameter you change the entire outcome to the way you want it.

JB Rhinehart, Realist

A-Body's RULE!
Re: Friend Needs 1970 340 Heads - Advice? [Re: Rhinodart] #2995634
12/15/21 08:39 PM
12/15/21 08:39 PM
Joined: Jan 2003
Posts: 9,000
Freeport IL USA
P
poorboy Offline
master
poorboy  Offline
master
P

Joined: Jan 2003
Posts: 9,000
Freeport IL USA
If the car is a street car and does not need to be the fastest car on the track and doesn't need factory matching numbers, the standard issue 360s heads are bolt on. Mopar used them on the 340 in 73. The extra emission ports on the newer LA heads can be plugged and the heads work fine.

Re: Friend Needs 1970 340 Heads - Advice? [Re: Rhinodart] #2995635
12/15/21 08:39 PM
12/15/21 08:39 PM
Joined: Jan 2003
Posts: 6,029
Abilene, Texas
F
fastmark Offline
master
fastmark  Offline
master
F

Joined: Jan 2003
Posts: 6,029
Abilene, Texas
I agree with Rhino. Found out the details. If you need a set of iron heads, I have a customer that has a set of ready to go, late 70 dated 915 heads from a 340. Long story why he doesn’t need them after he had them all freshened up. Pm me if you want to discuss them.

Re: Friend Needs 1970 340 Heads - Advice? [Re: Rhinodart] #2995671
12/15/21 11:08 PM
12/15/21 11:08 PM
Joined: Jan 2003
Posts: 8,032
Highland, MI.
Sunroofcuda Offline OP
master
Sunroofcuda  Offline OP
master

Joined: Jan 2003
Posts: 8,032
Highland, MI.
His engine guy in CA. checked them out - I don't think either of us know the minute details. I'm guessing they are cracked. He said the heads are junk.


No Man With A Good Car Needs To Be Justified
Re: Friend Needs 1970 340 Heads - Advice? [Re: Sunroofcuda] #2995692
12/16/21 02:11 AM
12/16/21 02:11 AM
Joined: Aug 2003
Posts: 39,264
Bend,OR USA
C
Cab_Burge Offline
I Win
Cab_Burge  Offline
I Win
C

Joined: Aug 2003
Posts: 39,264
Bend,OR USA
Many shops will say they are junk heads if the valve seats are sunk and stock early heads with non-hardened seats for leaded fuel like they came with in 1970 shruggy
Most cracks can be fix by most good machine shops scopeup
Good luck luck


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Friend Needs 1970 340 Heads - Advice? [Re: Sunroofcuda] #2995697
12/16/21 02:38 AM
12/16/21 02:38 AM
Joined: May 2006
Posts: 1,170
Phila
P
PhillyRag Offline
super stock
PhillyRag  Offline
super stock
P

Joined: May 2006
Posts: 1,170
Phila
Quote
running 318 in it, but the original 340 came with it. He just found out the heads are no good


Which heads are junk?

Find some nice mid-70's or so nice 360 heads. Hopefully from some full size car that hasn't been "raced".
But not the smog ones.
Lots of 340's were driven hard early on.
After all: the 340-6 heads were based on a 360 head casting.
X-heads seem to have some "mystical" following, that ups the price for them.
Once installed, the difference is visibly nil.

Re: Friend Needs 1970 340 Heads - Advice? [Re: PhillyRag] #2995702
12/16/21 06:26 AM
12/16/21 06:26 AM
Joined: Nov 2020
Posts: 348
Isle of Sheeps
Gtxxjon Offline
enthusiast
Gtxxjon  Offline
enthusiast

Joined: Nov 2020
Posts: 348
Isle of Sheeps
Plenty of 'J Heads' around...

If they were good enough for the T/A engines they is good enough for me lol...

Yes they do crack across, to the spark plug mainly on the intake seat.

I have run them like this, but a new seat would easily fix this problem.

They can be ported to easily run 400hp and more!

This is me copying a Weslake Engineering Demo cutaway J-head from 1970... luck

J head porting.jpg340 J- head port floor to wall mods.jpg340 J cutaway with floor template.jpg
Last edited by Gtxxjon; 12/16/21 06:34 AM.

Carpe diem, quam minimum credula postero, thanx Horace!

There’s no point trying to fix stuff that ain’t broke,,, 'but if ain’t broke',,, you is not trying hard enough...
Re: Friend Needs 1970 340 Heads - Advice? [Re: Gtxxjon] #2995704
12/16/21 06:46 AM
12/16/21 06:46 AM
Joined: Nov 2020
Posts: 348
Isle of Sheeps
Gtxxjon Offline
enthusiast
Gtxxjon  Offline
enthusiast

Joined: Nov 2020
Posts: 348
Isle of Sheeps
The old Mopar performance book...

The best advice for iron heads on the Planet!

Once you read this, all the new stuff is just Chinese copies lol...

Everything that is around now was done over 50 years ago,,, 'ALREADY' LOL... drinking

Bob Mullen the god of small block iron heads... beer

YES that top picture says 500 horses, 'back in the day'... eek

Mopar performance book.jpgBobby Mullen TA heads.jpeg
Last edited by Gtxxjon; 12/16/21 06:50 AM.

Carpe diem, quam minimum credula postero, thanx Horace!

There’s no point trying to fix stuff that ain’t broke,,, 'but if ain’t broke',,, you is not trying hard enough...
Re: Friend Needs 1970 340 Heads - Advice? [Re: Sunroofcuda] #2995764
12/16/21 11:03 AM
12/16/21 11:03 AM
Joined: Apr 2003
Posts: 11,485
Looking for a way out of Middl...
IMGTX Offline
I Live Here
IMGTX  Offline
I Live Here

Joined: Apr 2003
Posts: 11,485
Looking for a way out of Middl...
I agree with the others.

Find out what the problems are.

I took a 340 head to a very reputable head shop and they said the head could not be fixed.

I took it down the street to a shop that worked with race cars and he said no problem. He put a new seat in the head and I put another 100K on the motor.

The first shop was all about in and out fast and didn't want to spend the time to actually fix it.

Re: Friend Needs 1970 340 Heads - Advice? [Re: IMGTX] #2995926
12/16/21 08:47 PM
12/16/21 08:47 PM
Joined: Jan 2003
Posts: 9,000
Freeport IL USA
P
poorboy Offline
master
poorboy  Offline
master
P

Joined: Jan 2003
Posts: 9,000
Freeport IL USA
Maybe the guy running the shop that said your heads are junk has a buddy that wants them, or may already have them... If you want them back, he will send you the busted heads off his buddy's motor.

Re: Friend Needs 1970 340 Heads - Advice? [Re: poorboy] #3002953
01/07/22 06:03 PM
01/07/22 06:03 PM
Joined: Jan 2003
Posts: 8,032
Highland, MI.
Sunroofcuda Offline OP
master
Sunroofcuda  Offline OP
master

Joined: Jan 2003
Posts: 8,032
Highland, MI.
Originally Posted by poorboy
Maybe the guy running the shop that said your heads are junk has a buddy that wants them, or may already have them... If you want them back, he will send you the busted heads off his buddy's motor.


Yes - most likely!

OK, so he has found a set of 340 heads advertised. I'll post the info & photo - does he want these, or not?

340 Heads Gordon.png

No Man With A Good Car Needs To Be Justified
Re: Friend Needs 1970 340 Heads - Advice? [Re: Sunroofcuda] #3003081
01/08/22 06:58 AM
01/08/22 06:58 AM
Joined: Jan 2003
Posts: 6,029
Abilene, Texas
F
fastmark Offline
master
fastmark  Offline
master
F

Joined: Jan 2003
Posts: 6,029
Abilene, Texas
Originally Posted by Sunroofcuda
Originally Posted by poorboy
Maybe the guy running the shop that said your heads are junk has a buddy that wants them, or may already have them... If you want them back, he will send you the busted heads off his buddy's motor.


Yes - most likely!

OK, so he has found a set of 340 heads advertised. I'll post the info & photo - does he want these, or not?



Until you get your old heads and find out why then were condemned, you may be wasting money on onother set of heads. First find that out. If you can’t deal with that shop, get another one. You have to find a good machine shop that you can trust and communicate with first. The heads my customer has are 915 from a 71 340 with 2.02 valves. I sent them to the machine shop for minor repair and then after they were fixed, he changed his mind and wanted a 4.00” stroke motor with alum heads. So we spent almost $900 on heads we will not use. They have been decked, magnufulxed, HP valve job, cut for the best seals and assembled with springs. I use a very good shop. He does excellent work. He does not work for nothing or steal parts. I figure these to be worth $900-$1000 is all.

I don’t know what your friends budget is. Usually budget work bites you in the but. These used heads may be small valve 360 heads not 340 heads so you’ll have to buy new valves right off. You don’t know what condition they are in in the first place. The price is very fair if they are good cores. I’ve got plenty of cores like that.

Last edited by fastmark; 01/08/22 07:00 AM.
Re: Friend Needs 1970 340 Heads - Advice? [Re: fastmark] #3003144
01/08/22 12:32 PM
01/08/22 12:32 PM
Joined: Jul 2011
Posts: 935
Chicago
PurpleBeeper Offline
super stock
PurpleBeeper  Offline
super stock

Joined: Jul 2011
Posts: 935
Chicago
If it was ME (which it isn't), I'd look for a set of heads like fastmarks and just swap them out if building a street motor. If I've got extra cash, I'd buy some aluminum heads. My last choice would be rebuilding the original heads unless the car is a "numbers car" and the head is somehting special on your car, which I don't think is the case. My 2-cents


70 Roadrunner convt. street car 440+6, NOS, 4-spd, SS springs '96 Mustang GT convt. street car '04 4.6 SOHC, NOS, auto, lowered "Officer, that button is for short on-ramps"
Re: Friend Needs 1970 340 Heads - Advice? [Re: PurpleBeeper] #3003185
01/08/22 02:50 PM
01/08/22 02:50 PM
Joined: Sep 2003
Posts: 15,957
north of coder
moparx Online content
"Butt Crack Bob"
moparx  Online Content
"Butt Crack Bob"

Joined: Sep 2003
Posts: 15,957
north of coder
Originally Posted by PurpleBeeper
If it was ME (which it isn't), I'd look for a set of heads like fastmarks and just swap them out if building a street motor. If I've got extra cash, I'd buy some aluminum heads. My last choice would be rebuilding the original heads unless the car is a "numbers car" and the head is somehting special on your car, which I don't think is the case. My 2-cents



iagree ^^^^^^
as to the rebuild vs new aluminum heads, i would just bite the bullet and get the aluminum heads. rebuilding the old iron pieces and doing them right, you will have as much, and most likely more money invested. unless, of course, this NEEDS to be a numbers build. [as has already been mentioned]
just my opinion as well.
your mileage will vary.
beer

Re: Friend Needs 1970 340 Heads - Advice? [Re: moparx] #3004047
01/11/22 08:27 AM
01/11/22 08:27 AM
Joined: Nov 2020
Posts: 348
Isle of Sheeps
Gtxxjon Offline
enthusiast
Gtxxjon  Offline
enthusiast

Joined: Nov 2020
Posts: 348
Isle of Sheeps
Very sound advice indeed!

Without a machine shop you can trust, you are in deep poo-poo!
Realistically a full re-vamp of any iron head is $500 per side.

You can buy a new aussie iron head and fit the parts yourself, $350...

Or for $1800 you can buy an Edelbrock or trickflow ali head.

Most folks would always say ''go new'' its not worth messing with 50 year old JUNK!

Speeedmaster 340 head.jpg
Last edited by Gtxxjon; 01/11/22 08:28 AM.

Carpe diem, quam minimum credula postero, thanx Horace!

There’s no point trying to fix stuff that ain’t broke,,, 'but if ain’t broke',,, you is not trying hard enough...






Powered by UBB.threads™ PHP Forum Software 7.7.1