A66 Challenger Registry

[6bblgt]

plenty of "J" heads for 1970 340s - just none of them during calendar year 1969 (where the changeover from "X" cast #2531894 to "JUO"  cast #3418915 is the question)

[kawahonda]

plenty of "J" heads for 1970 340s - just none of them during calendar year 1969 (where the changeover from "X" cast #2531894 to "JUO"  cast #3418915 is the question)

Yep, and if 100% true, I have myself a conundrum when I rebuild my 340, which has J-heads. My guess is the owner had a "head rebuild" and they just used off-the-shelf J-heads. Do I invest a boatload of money in X-heads (which are not any better as long as the J heads have 2.02 valves), or just refurbish my current heads. Current engine has great compression. How important is it to see that "X" for a 1970 Challenger that was built in November '69?

How far down the rabbit hole do you want to go. I guess that's for me to answer. It doesn't make sense paying $1000 for rusted "X" heads that are not better than what I have. Ugh. At some point, the history of the car becomes more important than A66 history. The man had a head rebuild and the shop used "J" heads. That's part of the car's history, which I have documented more than A66 history. Slapping on "X" heads erases that.

My thought is that the "J" heads belong on the car, and will stay..even with a blue-printed rebuild.

[340challconvert]

plenty of "J" heads for 1970 340s - just none of them during calendar year 1969 (where the changeover from "X" cast #2531894 to "JUO"  cast #3418915 is the question)

Yep, and if 100% true, I have myself a conundrum when I rebuild my 340, which has J-heads. My guess is the owner had a "head rebuild" and they just used off-the-shelf J-heads. Do I invest a boatload of money in X-heads (which are not any better as long as the J heads have 2.02 valves), or just refurbish my current heads. Current engine has great compression. How important is it to see that "X" for a 1970 Challenger that was built in November '69?

How far down the rabbit hole do you want to go. I guess that's for me to answer. It doesn't make sense paying $1000 for rusted "X" heads that are not better than what I have. Ugh. At some point, the history of the car becomes more important than A66 history. The man had a head rebuild and the shop used "J" heads. That's part of the car's history, which I have documented more than A66 history. Slapping on "X" heads erases that.

My thought is that the "J" heads belong on the car, and will stay..even with a blue-printed rebuild.

Just some information on X  Heads, really no big advantage of one over the other:894 heads:
1} ~ #2531894 'X-Head'................July 1967 - thru - October 1970 'Casting'
Note; Called the 'X-Head'
Note; Generally considered the 'best' 340 Cylinder Head. Consistent 'Port Measurements' of 160 CC's Intake and 70 CC's Exhaust.
Note; The 'tightest' Combustion Chambers with levels between {67.0 to 69.0 CC's}.
Note; The 'X-Head' has the best Intake CFM Flow at High RPM's.

2} ~ #2531894 'X-Head'........................ October 1970 - thru - June 1971 'Casting'
Note; Also with consistent 'Port Measurements' of 160 CC's Intake and 70 CC's Exhaust.

Note; These later 'X-Head' Castings will have approximately +2.0 CC greater Combustion Chamber volume, usually between {69.0 to 72.0 CC's}.
Note; When these later Castings were machined by the Factory, less material was removed from the Head Deck Surface than early Castings.
Note; This was done to lower the 340 Engine's Compression Ratio from 10.5-1 to 10.3-1 to meet the EPA's Emissions at lower RPM's.

[340challconvert]

x heads vs others;

1968-1969-(first half) 1970 model year 340s used "X" heads cast # 2531894 with 2.02"/1.60" valves

(second half) 1970-1972 model year 340s used "J", "O", "U", "Z" heads cast # 3418915with 2.02"/1.60" valves (at some point & on 360s with 1.88"/1.60" valves)

340+6 T/A heads are "J", "O", "U", "Z" heads cast # 3418915 with offset intake pushrod holes and 2.02"/1.60" valves

1973 model year 340s used heads cast # 3671587 with 1.88"/1.60" valves (also used on 360s)

[340challconvert]

Going back into an old file; found a beautiful A66 y1, 4 speed car with a black interior and black bumble. Car has pdb, and chrome Magnum 500 wheels w e60-15 tires and Black out hood. Sold for a very reasonable $35K in the April 2014 Mecum auction

[Mark_B]

Here's a shot of my A66 with some new deeper dish 15x8  TT's.

[340challconvert]

Here's a shot of my A66 with some new deeper dish 15x8  TT's.

Looking really good. I like the stance of the car with the deep dish wheels!
The RT style side stripe really sets the car off.

[340challconvert]

The A66 Registry now has full or partial data on 129 A66 cars.
I drill down as specific as possible on option details so that I can determine percentages of certain details. I am started to see patterns in color selections, when V8 emblems were used, when hood decals/metal callouts were started/ended, ratio of automatics to 4 speeds, build dates, percentages of cars with the A62 rallye dash, how many of our cars came w factory AC, what type of radio was factory installed, how many factory hood pin cars?, how many rare WSS A66 Challengers were made?.
This is just part of what I track. As always; registering your car will help the information grow. Thank you[   

[Mark_B]

Thanks.  I used a none designated stripe, so it's not pretending to be an R/T.

[DeathProofCuda]

@ Mark_B, great looking car.  Can you post some pics showing the side view with the new TTs?  I'm thinking about getting some day-2 wheels for my car and keep going back and forth between Torq Thrusts and slots. 

[Mark_B]

Here we go.

[DeathProofCuda]

Here we go.

Thanks    PM sent.

[340challconvert]

A66 Go Mango/orange interior 4 speep, Project car For Sale with most parts going with it. Non original motor. Chassis looks very clean and needs assembly. Car is in Texas

http://topclassiccarsforsale.com/dodge/414635-rare-1970-dodge-challenger-340-4-speed-a66-package-car-rare.html

[340challconvert]

Would love to see the tag on this one!  N96 would be a coup!

[benlavigne]

Not an original N96, unfortunately! Not a very long window of opportunity to get a Shaker on an A66, as it was made available on April 13, so less than three months... Have not seen any yet, @6bblgt , any numbers on N96 production, combined with A66?
THis one does have C15 Deluxe Belts, also a rare option!

Ben