Aluminum Head on an S-15 motor

[grubby65]

I just purchased an aluminum head (part #695795) to put on a S-15 DeSoto 25" motor.  I'm new to the aluminum heads on a flat head, I was wondering if you guys might be able to answer some questions for me?

1)  Would you use the copper head gasket or the more modern Fel-Pro sandwich style (7256-C)

2)  Would you use head bolts or studs.  I'm assuming with either I should use hardened washers.

3)  I have read the aluminum heads used a different spark plug.  If true do you know what number they are.

 

I guess any other thoughts or concerns anyone has I am willing to listen.

Thanks.

[Sniper]

I plan to use the Felpro on my aluminum head setup, a Dodge 230.  I understand they are more forgiving in this application.  Iron block, aluminum head.

 

Studs or bolts, in my mind either will work, I will be using both in my setup.  Hardened washers are a must, with a dab of oil between the washer and bolt head/nut to prevent galling of the aluminum.

 

No idea on the plug question though. 

[martybose]

I don't know what head you have, but if my Edmunds is any indication they may have gone from a 1/2" thread length to a 3/4" thread length.  You should measure the length of the threads in the head to be sure.  I used an Autolite AP 646 in my head, but had problems with the gap being closed because the sparkplugs were over the valves, had to use indexing washers to move it out slightly.  Hopefully yours aren't!

 

Marty

[greg g]

What brand of aluminum head are you installing? I had an Edmunds on mine and the stock plugs are not long enough.  The electrode is shrouded.  They do not water past the threads of the plug hole. So you do need plug with longer threads o put the electrode into the combustion chamber but not so long as to interfere with the valve. And most aftermarket heads do not use the stock plug location they tend to center the plug rather than the factory offset. 

Edited January 16, 2021 by greg g

[grubby65]

It is a factory aluminum head. The Chrysler part# is listed in the original post.  

[HotRodTractor]

4 hours ago, grubby65 said:

It is a factory aluminum head. The Chrysler part# is listed in the original post.  

I would measure to verify - but I seem to recall the factory aluminum head I once had used the same plugs as the cast iron head. I never installed it, so I could be wrong.