Small Block heads for sale, U and X head

[Cbridgewater]

Bought these heads for my 340, found out after magging that the U head has some cracks that I really don't want to mess with. The X head is crack free. Both are 2.02/1.60 valves. Again, U head has some cracks between valves and between plug and valve. Make me an offer! Buyer will of course pay all shippings costs.

[Cbridgewater]

Here is the X head

[Cuda_mark]

I've never owned a small block but I always wondered what the difference was with U vs X.

Did the TA's and AAR's come with the X heads?

[blown motor]

I've never heard of U heads. Were they very common? What engine and era?

[formula_s]

I've never owned a small block but I always wondered what the difference was with U vs X.

Did the TA's and AAR's come with the X heads?



J heads.

[Cbridgewater]

Took another look this morning. The U head has a 360 stamp on it, while the X head has a 340 stamp. From what I understand, both can be used on a 340.

[6bblgt]

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 # 3418915 with 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)

[kawahonda]

6bblgt, can you elaborate a little more?

What would a November '69 built Challenger 340 have?

[6bblgt]

IMO the transition from "X" to the 915 head was somewhere around the end of calendar year 1969 (I'd expect "X" heads on a Nov. '69 car)

@Cbridgewater can you post pics of the cast date codes?  & where's your location?

anyone have a "915" head with a 1969 date on it?

[Cbridgewater]

Located in California near Modesto. I'll get a photo this afternoon.

[kawahonda]

Yep, I think you're right. My J heads were made July 8th, 1970.

No one has been able to produce a photo of a 69' built J head (915) that I've seen.

[Teslasbrain]

OP, can you post a picture of the date codes?

http://www.cuda-challenger.com/cc/index.php?topic=119591.0

[Cbridgewater]

Here are pictures of the stamping on the head.

[kawahonda]

OP, can you post a picture of the date codes?

http://www.cuda-challenger.com/cc/index.php?topic=119591.0

I would love to see evidence that ANY 1970 Challenger got a "J" head!

[1 Wild R/T]

How about a 70 Cuda?  Got one in my shop right now with J heads...  Prior to me it was un-molested... I on the other hand have molested it.... Just call me Chester...