Which Head Should I Use?

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zfriedbauer

zfriedbauer

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Hey guys, I have a 1974 Slant head with the spark plug tubes, and a 1976 slant head without the tubes. ( i think they call those a peanut head?) Im getting an old style valve cover because i like the way those look better, and Im looking into getting a set of 198 (7.005) Connecting rods and different pistons to build a "long rod" Slant 6. While i like the 1974 head better, is one of these better for general use overall? will one or both conflict with my rods or valve cover? Thanks in advance Guys!
 
I've had nothing but the tube type, but have been told that the peanut head is better for performance with porting and bigger valves.Again just something I was told.
 
I believe the peanut head is the combustion chamber shape, which started in the late 60's But no need to guess: read all about it in the 'Articles' section of www.slantsix.org. All your questions will be answered.
 
'All "no spark plug tube" heads, using the small B-series spark plugs (peanut plugs) have the later revised chamber design'

Hence the peanut plug head name (peanut head for short)
 
so using the 76 head without tubes would be best? im looking mild performance. tubes appear stock which i prefer, but if the peanut head works better may as well give that one a go.
 
It's really a personal opinion type thing IMO. I hear the drool tube heads are lighter, which is slightly better if you're into shaving pounds, but it sounds like the peanut head isn't as troublesome when porting/bigger valves. Oh, I think the tube head has a wider selection of spark plugs, but I may be wrong. Also, I've heard you can remove lifters on the tube heads without removing the head? I've only messed with later peanut heads, so I couldn't tell you much there.
 
Brandon Weaver said:
Also, I've heard you can remove lifters on the tube heads without removing the head? I've only messed with later peanut heads, so I couldn't tell you much there.
Click to expand...
Correct... pull the spark plug tubes and they are wide open for lifter removal.....if the varnish rings on the lower edges of the lifters will let them go!
 
Says on there: " it is worth the effort to locate and use the 1968 and later head in order to get the most out of your efforts and your SL6. The new chamber shape can be found in heads with and without the spark plug tubes."

So i guess it really just comes down to which one will cost less to clean up.
 
Bingo! Hope it works out well. If you are not going for a substantial cam and porting it out for breathing for top end RPM's, I am not sure you will see much difference anyhow since both of your heads supposedly have the same chamber. You only mention what your plans are for the bottom end. What is your general use or purpose for the engine?
 
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