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Peanut Head
https://slantsix.org/forum/viewtopic.php?t=34683		 Page 1 of 2
Author:  stonethk [ Sat Apr 04, 2009 7:08 am ]
Post subject:  Peanut Head
I acquired a "peanut" head. I noticed little holes in the exhaust bowls- for air injection I believe.
I want to run this head on my 170.
Are these holes going to be a problem?
Coupla things about the head when I received it:

-Only identifying marks on it are BH AAWJ, a pointer pointing to 3 dots, a number 8 cast into it, and, TORQUE S/PLUGS 10 FT/LBS cast.

-Small pushrod holes.
Author:  SlantSixDan [ Sat Apr 04, 2009 8:28 am ]
Post subject: 
The factory air injection blockoff plate P/N 3751 249 is still available from the dealer; it's quite beefy to deal with the thermal cycling and exhaust pressure. Blockoff gasket is P/N 4275 834. You'll want to CC that head; you may wind up milling it to get reasonable compression.
Author:  stonethk [ Sat Apr 04, 2009 8:36 am ]
Post subject: 
Tahnks for those #'s Dan, It looks to be milled already, but, yeah gonna CC it anyways.
Author:  Aggressive Ted [ Sat Apr 04, 2009 9:06 am ]
Post subject: 
I am running that head, off a 78 pickup. You can also tap the hole and put a plug in it. Mine had also been shaved before I got it. So it only took another .060 to get to 46 cc. I also decked the block since it had twisted.

Great head, not problems with the air holes.
Author:  DusterIdiot [ Sat Apr 04, 2009 9:07 am ]
Post subject:  BL head
You won't have to plane it that much, I have quite a few of these and they have all fell in the 54-52 cc range... unlike the drool tube heads from various years that I've had that ran from 68 cc 60's heads to the couple 1974 heads that came off the engines at 54cc each.

-D.Idiot
Author:  stonethk [ Sat Apr 04, 2009 9:41 am ]
Post subject: 
Appreciate the info guys.
I got lucky, I bought it basically sight unseen, I don't think the guy who sold it to me knew what he had- BIG valves, bigger than my engnbuilder ones, double springs, new valve guides and seals, milled, minor porting & hardened seats besides the extra porting and unshrouding I did. I think the head is good to go.
I noticed a plug in it already as Ted described.

My Psychic Super-Highway Racer (my cars name) is one step further to being done. :D
Author:  Rick Covalt [ Sat Apr 04, 2009 2:01 pm ]
Post subject:  Question
I have the same peanut head with air injection and Have just completed the porting and was going to take it to the shop to be planed to ge the CR. up where it needed to be . The head has big valves that were installed by some else. The question is this. When I CC the head I come up with about 41 or 42 CC. I thought maybe the head was planed before, however there is a number and letter still etched in the bottom that looks factory to me. Is it possible that this head is actually 42CC or did the markings come from somewhere else. I was kind of bummed because I'm afraid this is too high of CR. Maybe not? :?: :?:

This 42CC puts my static compression ratio at 11.3 and a dynamic C.R. of 8.8. Is that CR. going to be able to run on premium gas?

Cam specs are here is that helps:

.510 lift, 282 duration, 62 degrees overlap and 110 LSA
@.050 246 duration, 26degrees overlap

If you want to double check my numbers:

3.430 bore, 42 CC , 3.66 Aussie head gasket, .045 compressed thickness, piston .071 down the bore, 4.12 stroke.

Help and opinions appreciated. This is not a daily driver. It will be an occasional weekend warrior.

Rick Covalt

Gettin ready for Mason Dixon Race !! :D :D
Author:  Rick Covalt [ Sun Apr 05, 2009 3:48 am ]
Post subject:  bump
Any thought on the 42 CC
Author:  sandy in BC [ Sun Apr 05, 2009 7:28 am ]
Post subject: 
Looks to me like you may have neglected to factor in the displacement of the cylinder between the piston and the deck.

Your build id similar to mine and I am at 9.5 CR
Author:  Dart270 [ Sun Apr 05, 2009 8:56 am ]
Post subject: 
His comp numbers are right - just checked. Good to know about the later heads having smaller cc numbers from the factory.

I say run a bit bigger cam and pump gas will be OK. Might even be OK with that cam and would be a worth a try. Set total mech timing at 25-28 deg.

Lou
Author:  Rick Covalt [ Mon Apr 06, 2009 7:02 am ]
Post subject:  Going ahead
Well, I talked to my son and he doesn't mind running a little Race fuel if need be. The cam / short block is already together and ready to go so we are not changing the cam. We will see how it does. I am still a little puzzled that I have not heard of any heads with this small of a chamber. I figured we would need to plane some to get to 10.5 CR.

Rick
Author:  Charrlie_S [ Mon Apr 06, 2009 9:21 am ]
Post subject:  Re: Question
Quote:
. The head has big valves that were installed by some else. The question is this. When I CC the head I come up with about 41 or 42 CC. I thought maybe the head was planed before, however there is a number and letter still etched in the bottom that looks factory to me. Is it possible that this head is actually 42CC or did the markings come from somewhere else.
D
Rick, I would bet the head has been cut, already, since someone has installed big valves.

Measure the thickness of the head from the valve cover surface to the head deck surface. If it is uncut, that measurement should be about 3.600 inches. It can vary slightly. I have seen from 3.595-3.610 on heads I have removed from stock engines. If you measure about 3.500 you can bet the head has been cut .100, already.
PS: it is possible to do this meadurement, even with the head installed.
Author:  68barracuda [ Mon Apr 06, 2009 10:59 am ]
Post subject: 
Rather odd if you compare it to my heads whopping 59cc chambers
Author:  Rick Covalt [ Mon Apr 06, 2009 1:26 pm ]
Post subject:  Thanks Charlie
Thanks for that measurement Charlie. It is at the shop getting the valves touched up. When I get it back I'll try to measure it. The odd part is the number and letter, B 7, that is still on the underside of the head. If it has been planed that obviously would not be there. It is a very shallow, very fine number and letter. Only a couple thousands deep. Has anyone else seen such markings on the face of the head. I believe it was our at the edge between number 4 and 5 cylinder.

Rick
Author:  68barracuda [ Mon Apr 06, 2009 3:03 pm ]
Post subject: 
The Text from the gasket partnumber is imprinted on the deck of my head
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