ZL-1 heads? - Team Camaro Tech
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post #1 of 16 (permalink) Old Mar 19th, 01, 05:10 PM Thread Starter
 
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OK,a quick question regarding an engine I picked up recently.Came out of a '63 vette race car that the owner is now restoring.Block is a #512 standard bore,Crank#6223 making it a 'home-made' 427.The heads are what I'm confused about;they're alum. #074's.What's strange is that they have bolt holes through two of the intake runners which I have read is only found on ZL-1 heads.Problem being that they are dated 1970.Anybody have any ideas/info.??
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post #2 of 16 (permalink) Old Mar 20th, 01, 03:36 AM
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All of the 3946074 heads had provisions for two additional studs (per head) that were used in conjunction with the additional bosses on the ZL-1 aluminum block.

In the event that the heads were used in a non ZL-1 application (a second design 1969 L-88 or 1971 LS-6 for example), the studs were still present in the heads, as something was needed to seal the holes in the intake ports in the heads. I was fortunate to look at a rough, but relatively untouched 1971 LS-6 Corvette this past weekend and this is how it was done. It looks a bit odd to see the ends of the studs just hanging down like that...

In any case, the holes in the intake runners are going to have to be sealed in some manner. There is also a machine shop somewhere in the Cleveland, OH area that can weld the bosses onto a cast iron block for those so inclined.

Hope this helps.

Regards,

Stan Falenski
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post #3 of 16 (permalink) Old Mar 20th, 01, 01:31 PM
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I also have a set of 074# aluminum heads with the treaded holes, I found the # in a chevy book and it also listed them for a LS6, is there such thing as a alum. head LS6.

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69 camaro conv. SS 396 th400. matching numbers, hugger orange, white top, white houndstooth int.(changed color combo)
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post #4 of 16 (permalink) Old Mar 20th, 01, 03:30 PM Thread Starter
 
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<BLOCKQUOTE>quote:</font><HR>Originally posted by Rowdy Rat:
All of the 3946074 heads had provisions for two additional studs (per head) that were used in conjunction with the additional bosses on the ZL-1 aluminum block.

In the event that the heads were used in a non ZL-1 application (a second design 1969 L-88 or 1971 LS-6 for example), the studs were still present in the heads, as something was needed to seal the holes in the intake ports in the heads. I was fortunate to look at a rough, but relatively untouched 1971 LS-6 Corvette this past weekend and this is how it was done. It looks a bit odd to see the ends of the studs just hanging down like that...

In any case, the holes in the intake runners are going to have to be sealed in some manner. There is also a machine shop somewhere in the Cleveland, OH area that can weld the bosses onto a cast iron block for those so inclined.

Hope this helps.

Regards,

Stan Falenski
<HR></BLOCKQUOTE>

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post #5 of 16 (permalink) Old Mar 20th, 01, 03:56 PM
 
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After '69 these heads only came on the '71 LS-6 Corvette or were sold over the counter. There are a bunch of these around w/ 1970+ date codes.
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post #6 of 16 (permalink) Old Mar 21st, 01, 06:04 AM
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I tougth i read in a few books that the LS6 alum. head was planed but not produced.

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69 camaro conv. SS 396 th400. matching numbers, hugger orange, white top, white houndstooth int.(changed color combo)
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post #7 of 16 (permalink) Old Mar 22nd, 01, 12:04 AM
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And also do these heads need speacial head bolts with washers and different length.

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69 camaro conv. SS 396 th400. matching numbers, hugger orange, white top, white houndstooth int.(changed color combo)
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post #8 of 16 (permalink) Old Mar 22nd, 01, 04:39 AM
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They made 188 1971 Vettes with the LS6. It had aluminum heads and was rated at 425 hp due to lower compression. I have one sitting here with 38K orig. miles that I sold to a friend a couple months ago. Very Rare car.
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post #9 of 16 (permalink) Old Mar 22nd, 01, 07:50 AM
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I was wondering what ever happened to that car Charlie.... One heck of a car!

I only wish that I could have scraped together the cash to buy it myself!

Regards,

Stan Falenski
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post #10 of 16 (permalink) Old Mar 22nd, 01, 08:05 AM
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Burney,

1970 LS-6 Chevelles/El Caminos used a closed chamber cast iron head.

1971 LS-6 Corvettes used an open chamber aluminum head.

From what I recall, the head bolts are identical to other big block Chevy hardware, but require a hardened steel washer to protect the aluminum from galling. The part number for the washer is 3899696 and was available from GM as of a couple years ago... Sixteen per head are required.

Hope this helps.

Regards,

Stan Falenski
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post #11 of 16 (permalink) Old Mar 24th, 01, 11:44 AM
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Thanks Rawdy Rat, I was asking because there is galing around my bolt holes.

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69 camaro conv. SS 396 th400. matching numbers, hugger orange, white top, white houndstooth int.(changed color combo)
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post #12 of 16 (permalink) Old Mar 24th, 01, 11:48 AM
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And also, if I wanted to use them on a stock block could I put a bolt the right lenght with loctite from under the head.

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69 camaro conv. SS 396 th400. matching numbers, hugger orange, white top, white houndstooth int.(changed color combo)
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post #13 of 16 (permalink) Old Mar 26th, 01, 04:16 AM
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Burney,

Yes, the holes will need to be filled somehow. Either studs or threaded plugs should do the trick.

Regards,

Stan Falenski
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post #14 of 16 (permalink) Old Mar 27th, 01, 05:11 PM
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Use allen head set screws and loctite them in I never had a problem with them backing out.

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post #15 of 16 (permalink) Old Mar 28th, 01, 03:37 AM
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<BLOCKQUOTE>quote:</font><HR>Originally posted by oger:
..and loctite them in...<HR></BLOCKQUOTE>

By all means, whatever you use to close up the holes, make sure that you use some type of thread lock compound. The last thing you want is for a plug, stud, or set screw to work its way loose and into the engine when you're turning 6500 rpm or so...

Regards,

Stan Falenski

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