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what kind of heads
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Posted by: 406camaro

I am trying to find out what kind of heads these are.The # on them are 3991492.Also they are angle plug.Thanks

Posted by: GMR

A quick google search yielded this:

Quote:


	"492" – 3991492. Another good performance head. They were found on 1970 LT-1 engines. They had 2.02/1.60" valves, 64CC combustion chambers, DO have accessory holes, intake port volume should be 161CC's, exhaust port volume should be 62CC's. These heads have double hump casting marks. This particular casting head was also available as an "over the counter" head from GM in straight or angle plug configurations.

Looks like you got a decent head there.

LS

Posted by: skeezix

http://www.mortec.com/castnum.htm

Another spot that concurs with your findings, GMR.

Posted by: The OLE MAN

Chevrolet's first "slant plug" heads. Circa, '70 to '73, Basically a "stock" hi performance head of it's time. Replacement head for the "famed" "186" heads that were stock for Z/28's, LT-1's 2.02 int, 1.60 exh. valves, screw-in studs with guide plates. "Neat" but nothing really special. Also, never installed on factory engines, over the counter only. These were supposedly good for 10 to 15 H.P. over "stock", 2.02 straight plug heads, throughout the rpm band, tested.

The OLE MAN

Posted by: MadScientistMatt

I'm moving this to the GM Tech forum.

Posted by: 406camaro

Can you get decent hp out of these heads on a 400with a solid cam,1.6roller rocker,single plane intake and 11.5 to 12 compression.

Posted by: skeezix

Yes.

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