C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

old cast iron head info needed

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Old Feb 15, 2006 | 11:14 AM
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From: spring branch texas
Default old cast iron head info needed

Anybody have more info on casting # 340292 heads. I know they are 64cc angle plugs 2.02in 1.60ex but thats all I knnow about them
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Old Feb 15, 2006 | 11:48 AM
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They were used between 73-80 on 350s and have an angled plug, supposedly hard to find and are high-performance heads for 300hp+ engines.

Known as a 'Turbo' head available from GM over the counter.

I found some flow data on slightly ported ones:
.100 lift = 96.39cfm
.200 lift = 143.85 cfm
.300 lift = 190.14 cfm
.400 lift = 218.51 cfm
.500 lift = 243.59 cfm
.600 lift = 261.58 cfm
.700 lift = 271.18 cfm
This is at 25" on a 4" bore.
Not very much by todays standards but realize these were probably done around 1975, and have been hurt and repaired many times over the years, and the valves are pretty sunk, which hurts the flow a lot.

Out of the box should be 225-230 intake flow

Last edited by vader86; Feb 15, 2006 at 11:54 AM.
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Old Feb 15, 2006 | 12:02 PM
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From: spring branch texas
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so they are diffently better than my stock 85 heads
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