Cyl Head info needed !!!

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SS Lancer

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Ok so just tonight I finally pulled valve covers to see what cyl heads my 340 has on it and I found the following casting numbers # 3418915
I also saw 360 on other end of each cyl head so I assume after looking online I have
1971 360 heads .
do these particular heads have performance potential and if so how much with serious porting etc
thanks Chris .
 
Most heads have that “360” cast into it but that doesn’t mean there “360” heads.

WHat valve sizes?
 
I do have a 70
340 I ran the numbers last week.
Which means what for the heads in question?
I’m missing wht your statement means.
This is my casting number for the block
Im assuming with numbers I listed I have a set of 71
360 heads on my engine ?

Screenshot_2019-02-06-00-15-51.png
 
They started using the 915 heads on the 340 in mid year 1970...
 
look at the vin # on the block and the date code It might be out of a 71 car, also what is the date on the heads
 
Without moving the pushrod pinch you can get about 280 cfm out of an X head. A touch less with the other castings. Unless you are tied to that casting there are more economical choices out there.
 
Without moving the pushrod pinch you can get about 280 cfm out of an X head. A touch less with the other castings. Unless you are tied to that casting there are more economical choices out there.
Yes sir thank you !!
I have some decent alum heads to use but was just considering keeping these since they are getting kinda hard to find .
 
Unless you are forced to run them by class rules or just really like the idea of running a stock casting it will never be worth putting the $’s into them to get to that level. I view the money I spent on porting my x heads as money very well spent. That being said I wouldn’t even think about an X head if I wasn’t forced to run it. Think of what you could do with $2800-$3000 and a better casting or clean sheet of paper?
 
Ok so just tonight I finally pulled valve covers to see what cyl heads my 340 has on it and I found the following casting numbers # 3418915
I also saw 360 on other end of each cyl head so I assume after looking online I have
1971 360 heads .
do these particular heads have performance potential and if so how much with serious porting etc
thanks Chris .
#3418915 is a 71-72 340-360 head open chamber with 1.88/1.60 valves. Cast mark "J".
 
Unless you are forced to run them by class rules or just really like the idea of running a stock casting it will never be worth putting the $’s into them to get to that level. I view the money I spent on porting my x heads as money very well spent. That being said I wouldn’t even think about an X head if I wasn’t forced to run it. Think of what you could do with $2800-$3000 and a better casting or clean sheet of paper?
Yes sir good point !!
The only limitations imposed on cyl heads is stock valve angle and no off set rockers allowed .
 
#3418915 is a 71-72 340-360 head open chamber with 1.88/1.60 valves. Cast mark "J".

Not really, 68 69 were X heads 894 castings, 70 - 72 J heads 915, 70 & 71 340 had 915 2.02 1.60, 71-up 360 had 915 1.88 1.60, 72 340 had 1.88 1.60, 73 340 587 heads. I have seen chats that say different but over the years I have collected and sold many sets of heads off of 340's and this is what I have seen.
 
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