"X" or "TA" heads???

-

Alberto

Member
Joined
Nov 6, 2008
Messages
22
Reaction score
33
Location
Sarasota, FL
Hey Guys,
I want to properly identify these heads. I will give all the numbers I found on the head.
3418915 B. Then AAWJ 360. Another tiny plate that is screwed to the head "01090" . There are also several big "U"s stamped on it. It does have 2.02 / 1.60 valves. I looked on three different cast number charts and they all say that they are "TA".
The block is not a "TA" block, it is 2780930, with a 10/5/69 date code.
Are "TA" heads worth more than "X" heads?:popcorn:
THANK YOU everyone!!!:thankyou:
AL
 
ok....J U O heads use the same casting number as the TA head.....but the TA head has the intake pushrods drilled at an angle....and only use TA rockers.....

5182918-TAHead.jpg


e8a5_1.jpg


e265_1.jpg
 
T/A heads have offset intake pushrod holes. Some have a U between the plugs. All had 2.02 valves and some J heads had 2.02 valves in 71 340’s.
 
I saved this screen capture quite a while ago, I hope it helps;

x j o u z 340 355 360 ta heads etc.JPG
 
That is not a 'tell' in itself.

Adjustable 273 rockers fit X & normal 915 heads, 974s too.
 
That is not a 'tell' in itself.

Adjustable 273 rockers fit X & normal 915 heads, 974s too.

If they are using stamp steel rockers, we know they are Not TA heads.
If they have adjustable rockers then we look farther at the rockers.
 
Man you all are quick!!:thumbsup:
The push rod holes not offset, so "X" head it must be. THANKS AGAIN!!!!!!

If it / they have the cast in U they are 915 heads.

You also mentioned the 915 casting number.

Not all 915 castings are T/A heads.
 
I have had TA heads with U casting and also O. TA heads were 360 heads machined for offset pushrod to give more meat for porting. X heads would have an X on them, pretty simple.
"Are "TA" heads worth more than "X" heads?" Yeah that is an understatement.
 
Not an X head. It's a 2.02, 915 U head.

Nice heads by the way.

Damn, this is a bit confusing. So what is the difference between the "X" and "U" (or "O" & "Z" as stated in one of the above posts) heads? Does one flow better than the other? Different springs? :BangHead:
 
I have had TA heads with U casting and also O. TA heads were 360 heads machined for offset pushrod to give more meat for porting. X heads would have an X on them, pretty simple
"Are "TA" heads worth more than "X" heads?" Yeah that is an understatement.

Only to someone doing a resto on a AAR or TA.....otherwise they offer the same performance as a standard X or J head.....and If you were building a performance engine I would be looking at aluminum and not cast iron....JMO
 
The letters were used at the foundary to tell the differant heads apart when they were cast.
 
X heads end in casting number 894... nothing else for the 68-70 model years.

All the other letters for performance oriented passenger car heads started in 1970 model year with the 915 head that you have.
 
In NHRA stock eliminator we have found the x head to be the best flowing unported head. Also the chamber has a slightly different shape than the 915. You can run the piston a little bit closer to the head than on the 915 castings.
 
Damn, this is a bit confusing. So what is the difference between the "X" and "U" (or "O" & "Z" as stated in one of the above posts) heads? Does one flow better than the other? Different springs? :BangHead:

Unless they are TA heads nothing. The X heads all had 2.02 valves. "Some" J heads had 2.02 valves. I am not sure if any of the other letter heads did. But, unless they are TA heads, the only difference is either the 1.88 or 2.02 intake valve size. All the ports and chambers are pretty much the same. Even in stock form, the TA heads are the same except the 2.02 valves and the offset pushrods for porting the intake ports out. I believe even the ports in the TA heads are all the same as the rest in stock form.
 
In the stock form there is the differant cfm between the differant heads. Once they are all ported to say 250 cfm at .500 lift with cc and valve sizes the same, J U or O or no letter on the head doesn't really matter.
 
-
Back
Top