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Old October 9th, 2017, 06:53 PM   #1
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350 Olds Build Questions

I have a 350 Olds 77-80 with a Comp Cam XE262h, full length hedman headers, holley street dominator intake, holley Ultra 650 DP, true dual 40 series flowmaster, 3:73 gears, posi, and hei. Pretty basic. I just purchased some rebuild 7a heads. I would like the compression higher but my budget is not agreeing. Pistons, rings, and boring it out would be nice tho. I think Iíll just put my heads on and call it a day. What gaskets should I use? & will I see any difference from the 3A heads that I have ?

*I wanted a weekend cruiser. Not too much but more than stock in my 1987 Cutlass Supreme.
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Old October 10th, 2017, 07:27 AM   #2
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I used the .028" Rocket Racing head gaskets. Unfortunately, they are now on back order. With a 62-64cc chamber and the thin gasket, I came out right at 9 to 1. Smitty from M&J Performance had .011" thick shim gaskets for around $100 a pair. Also .027" reuseable but around $150 to $200 a pair gor the superior Cometic gaskets. I know the 77-80 Olds 350 uses a unique head gasket. I can't remember if you use early head gaskets when you switch heads. Expect 8.5 to 1 with Felpro replacements but those heads are definitely better. Stock valves or any milling? CC them and go from there.
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Old October 10th, 2017, 09:49 AM   #3
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I used the .028" Rocket Racing head gaskets. Unfortunately, they are now on back order. With a 62-64cc chamber and the thin gasket, I came out right at 9 to 1. Smitty from M&J Performance had .011" thick shim gaskets for around $100 a pair. Also .027" reuseable but around $150 to $200 a pair gor the superior Cometic gaskets. I know the 77-80 Olds 350 uses a unique head gasket. I can't remember if you use early head gaskets when you switch heads. Expect 8.5 to 1 with Felpro replacements but those heads are definitely better. Stock valves or any milling? CC them and go from there.
I have to get them checked out to see if the valves are stock or if any milling was done. They were definitely rebuild but not sure on the specs. Bought them from a guy but you can never be sure. Thatís a good question on what gasket Iím suppose to use...for my block or an earlier model block? The 9 to 1 compression with the thin gaskets...are there any issues I should worry about or go with a thicker one? Thanks for the info by the way
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Old October 10th, 2017, 09:44 PM   #4
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You can use copper coat gasket spray on the shim gaskets but there should be no issues with iron heads. A Performer RPM intake is a better choice for your current and one with slightly more compression. The 650 is borderline too small as well.

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Old October 11th, 2017, 07:38 PM   #5
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You can use copper coat gasket spray on the shim gaskets but there should be no issues with iron heads. A Performer RPM intake is a better choice for your current and one with slightly more compression. The 650 is borderline too small as well.
okay. Sounds great
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