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View Full Version : Open Chamber Heads on 69 L89 Corvettes?

SuperNovaSS
03-13-2013, 06:59 PM
Does anyone know if there is any truth to this claim?

3946074 Heads on Ebay (http://www.ebay.com/itm/121076592918?item=121076592918)

If there is truth to it, I am curious why GM would do it. The L89 was the L71 435HP tripower engine with aluminum heads. If they went to open chamber they would have to design a specific piston for the L89 427 application and make specific shortblocks for that application as well.

Any ideas?


Thanks,

Jason
Ls6 Ragtop
03-13-2013, 08:57 PM
I'm not buying it. I did my homework on these when I was looking for a set for a customers L89 Corvette recently. I can find no other application for the 68-69 396-427 L89 motors than the 842's which are of course closed chamber heads. He claims Camaro and Chevelles were also equipped with the 074 open chambers after January of 69? I have here possibly the last known L89 Chevelle built in 69 (August of 69 Atlanta build) with it's original drivetrain completely intact and somebody must have forgot to tell the assembly plant that it wasn't supposed to have 842's because it does.
Chris
Fast67VelleN2O
03-13-2013, 08:59 PM
074's were NOT used on L89's at all. Just ask the 1970 L89 Nova guys HAHAHAHAHA
olredalert
03-13-2013, 09:43 PM
----Once again,,,Do not trust this vendor! Do your homework when he is involved.......Bill S
kwhizz
03-13-2013, 10:11 PM
Awwww!!!!.........Nevermind!!!.........LOL
earntaz
03-14-2013, 08:35 PM
Did not some of the 427s have the 063 head? These were the first attempt at the "open chamber" design -- if I remember right, they were about 100ccs and used the 13/16 plugs w/gaskets.
SuperNovaSS
03-14-2013, 09:04 PM
The 063 head is closed chamber, oval port, and cast iron.


Jason
earntaz
03-14-2013, 11:43 PM
Jason -- that is what many call them ... but they are not like the 68' and older heads. The true "bath tub" shape of the chamber was changed on the 69' 063 heads. They are opened up on the spark plug side much like the newer open chambers but still use the large plugs. I have a set of these heads on a 440ci chevy with .180 closed chamber pop-ups. Compression comes in at approx 10.25:1.