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Discussion Starter #1 (Edited)
Hi Guys,
I just bought a 1967 L71 coupe and before putting the original engine back in it I thought I better put in some new valve seats to help deal with the low octane gas we have in California. Before doing so I thought I might lighten up the engine by putting on a set of L89 aluminum heads. New to this I don't know if they are avalible in the aftermarket stores or would I have to buy a set of used ones because they are not made anymore. Moreover, Do the heads offer any advantage/disadvantages over the stock heads other than less weight (I read about 60 lbs per head less).

Thanks,
Scott
 

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Anyone have any idea?
 

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I am no expert on this but I considered L-89 heads for my engine. From the specs I think L-71 and L-89 are virtually identical. The weight savings I think is more like 40 lbs per head less. The only other advantage I can think of is that the aluminum head may be a little more pump gas friendly.
 

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Discussion Starter #4
I am no expert on this but I considered L-89 heads for my engine. From the specs I think L-71 and L-89 are virtually identical. The weight savings I think is more like 40 lbs per head less. The only other advantage I can think of is that the aluminum head may be a little more pump gas friendly.
Thanks for the reply. I incorrectly refered to the heads as L88 heads when they truely are L89 heads. Are these still avalible? Through what company? Give the heads I have are in great shape but I want to clean up the ports and put in new valve seats I thought I'd not risk ruining them when porting and just go with a set of either aftermarket L89 aluminum heads (If they are made) or some other trick set up. I understand my engine (427/435 3 carb) puts out at least 435 hp and this is plenty of guts but I thought I'd just clean things up in the heads and put on some headers to be assured that I was getting all the 435 hp quoted. Any recommendations on what set I I should go with for a reliable street driven car and who it is in the San Francisco Bay Area that is a good mechanic to do the work?

Thanks,
Scott
 

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I don't know of any source for "new" L-89 heads but I do see originals on Ebay frequently. I think your L-71 and the L-89 heads are 106cc combustion chambers. You would need flat top pistons to get that down below 10:1 SCR to be pump gas friendly. The other issue is these are both square port heads and you have a square port manifold. If you go aftermarket, most of the square port stuff is high performance and kind of spendy.

Sounds like you want a good, fast, reliable, street driven car. I would try to find some L-89 heads in good shape. Have them built to your specs and go from there. You may be able to find new square port aluminum heads at GMperformance.com
 

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The book "Corvette 427" by Sherman says the L88 heads were no longer available from GM when he wrote the book. To the best of my knowledge, the aluminum heads on the L88 were the same as the L89. Production numbers were so low, I don't think GM would have had two castings.

Maybe someone makes a reproduction.
 

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'67 L89 heads

Hi Guys,
I just bought a 1967 L71 coupe and before putting the original engine back in it I thought I better put in some new valve seats to help deal with the low octane gas we have in California. Before doing so I thought I might lighten up the engine by putting on a set of L89 aluminum heads. New to this I don't know if they are avalible in the aftermarket stores or would I have to buy a set of used ones because they are not made anymore. Moreover, Do the heads offer any advantage/disadvantages over the stock heads other than less weight (I read about 60 lbs per head less).

Thanks,
Scott
Scott,
If you're still considering a set of GM aluminum heads, I have a nice of 392's. These are done and ready to go. They are a bit expensive, as I see them on "the" auction site @ $4000.00 and up to $6,000.00 (I don't know if they sell for that kind of money, but that's what they're listed for). I'd like to get $
$3,500.00 for these.
George
210 213 7004
 

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The book "Corvette 427" by Sherman says the L88 heads were no longer available from GM when he wrote the book. To the best of my knowledge, the aluminum heads on the L88 were the same as the L89. Production numbers were so low, I don't think GM would have had two castings.

Maybe someone makes a reproduction.
I agree why not use some aluminum heads from Jegs or Summitt??--Not cheap but have a warrenty to be as advertised--no dissapointments that way--Just a suggestion as that is what i'm thinking of doing to my 427 when i get it running--Good luck--Glenn:cheers: :cheers:
 

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Stock heads for the L-71 had 2.19/1.72 valves. L89 heads had 1.84 exhaust valves and are said to have about 20 HP more than L71 heads. Aftermarket offers a lot of choices with 2.19/1.88 and probably 2.25/1.88 valves. Weight reduction is 70 to 75 lbs. for the pair.
 

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GM still has a repoduction of the L-89 heads, 2.25 intakes, rectangle ports and the vane in the floor of the exhaust port. Oh, and they're aluminum. The Factory L-88 head was iron. They have a head that is advertised as being an NHRA legal replacement for them too. There are los of choices out there for BB heads.

:cheers:
 

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GM still has a repoduction of the L-89 heads, 2.25 intakes, rectangle ports and the vane in the floor of the exhaust port. Oh, and they're aluminum. The Factory L-88 head was iron. They have a head that is advertised as being an NHRA legal replacement for them too. There are los of choices out there for BB heads.

:cheers:
Sorry Tim but according to Noland L88 heads were Aluminum--and no longer available from GM--Glenn:smack :smack
 

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Sorry, I stand corrected. Here's a shot from GM Parts--

DESCRIPTION: HEAD
Aluminum Cylinder Head, NHRA Legal
This new aluminum cylinder head is a replacement for the 1969 L88 head P/N 14011076 used on 1969 Camaro and 1968-71 Corvette vehicles.

This head is similar to P/N 12363410 except that the intake ports are as cast, not CNC'd.

The valve seats can be machined to 2.19" intake and 1.88" exhaust or larger.

The rectangular port intake volume is 315cc, with square exhaust ports. The combustion chamber is 118cc and the valve guides start at 11/32", but can be machined to 3/8". Small Image Technical Notes: The casting is P/N 12363401.

That's what I get for going from memory. And I have a pair of IRON L-88 heads. At least the specs are the same, 2.19/1.88 rectangle ports open chamber etc.,

:cheers:
 
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