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6X heads?

7

71droptop

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Hi,
I am currently building a 69 400, 30 over with flat top pistons. I am looking for a good set of heads to use to keep my compression around 9.5 to 1 or so to be able to use pump gas. I have looked into Edelbrock heads and may go that way, but if I could go with Pontiac heads I would like to. I currently have a set of #62 heads, but was told the compression would be too high. I keep hearing about people using 6X heads with good results. I know there 6x-4 and 6x-8. Could either of these heads be used to reach my target compression? I know they have larger chambers. Could they be milled? Sorry for the novel and thanks in advance..
 
Has anyone had any experience with these heads? Good or bad? Any help would be appreciated. Thanks.
 
6X Heads

Use a dome piston. The 6X head will give you 8.5 to 1 if you are lucky... This information came from the machine shop where I just has my 400 freshened.
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Stick with the heads you have and use a thick head gasket. If you properly curve the distributor use a 160 degree thermostat and use at least 93 octane you will be fine.
 
I actually would like to stay with my original heads. Any suggestions on gasket thickness? Would the thicker gasket adversely affect intake port alignment or require me to buy longer push rods?
 
The gaskets arent that much thicker to have to mess with the intake and the push rods. Go to www.summitracing.com or www.jegs.com to see what is available. If they have it Felpro is an excellant brand to go with.
 
I had to repost this because apparently I timed out.
Thanks. I have been looking into the gaskets. There was some minor work done on the chambers. Valves were unshrouded. The heads cc'd out at 76. According to the chart on wallace racing, with a .030 overbore, that should put me at about 9.7:1 so I shouldn't need much more thickness on the gaskets.
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I dont think you have anything to worry about at that compression.
 
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