Grayghost

Is there a chart that list what heads came on what year 350 and a rating on what ones are better for flow, what chamber size they have, and so on.

2blu442

I haven't seen a list, but:

1968-69 used #5
1970 #6
1971 #7
1972 #7a
1973-77(?) #8

The #8 has a significantly larger combustion chamber, the others are pretty close to each other. For years I've heard the #5 are best, but I personally haven't seen data to show that. I think any of them would work well stock or with some porting.

Earlier 330 heads will also bolt on fine,
1964 #1 Used rocker arms on a rail, one year only setup
1965 #2 Screw in studs, stamped steel bridges between the rockers
1966 #3
1967 #4

Fun71

1968-1969 = 5
1970 = 6
1971 = 7
1972 = 7A (samll capital A)
1973-1976 = 8

The 5, 6, 7, 7A heads are all similar with 66-70 cc chambers. Typical intake valve is 1.88" but some performance versions had 2" intake valves.

8 heads have larger 79cc chambers.


There is this info from the Old FAQ but not all of it is accurate, such as the combustion chamber sizes - those are minimum specs allowed per NHRA rules and are not the actual sizes that came from the factory.

https://oldsjunction.classicoldsmobi...sfaq/ofhed.htm

joe_padavano

Here are all the SBO heads:

1964 - 1 and (late in the model year) 2 (used on 330)
1965 - 2 (used on 330)
1966 - 3 (used on 330)
1967 - 4 (used on 330)
1968-69 - 5 (used on 350)
1970 - 6 (used on 350)
1971 - 7 (used on 350)
1972 - 7A (used on 350, note small upper case "A")
1973-76 - 8 (used on 350)
1976 - 10 (used on 260)
1977-81 - 2A (used on 260)
1977-80 - 3A (used on 350)
1977-79 - 4A (used on 403)
1980-1985 - 5A (used on 307, VIN 9 only for 1985)
198?-8? - 6A (used on non-US market 307 without CCC)
1985-90 - 7A (used on 307, VIN Y only for 1985)

All 1976-older use 7/16" head bolts.
All 1977-newer use 1/2" head bolts.

olds 307 and 403

The two sets of #8 heads I measured were 77 to 78cc chambers. Measure first, unless you know the heads haven't been touched, these 350 motors are 40+ to 50+ years old, good chance someone was in there. Steel shim head gaskets is a good sign of a stock, untouched motor along with a nylon cam gear or what is left😉.

Grayghost

This 1975 350 has never been opened up. Yet.
Trying to figure out if I can work with the Heads on it, maybe mill them to lower the chamber size, and different pistons.
And cam change to get to 325-350hp. As this is more a fun cruiser than an all out bruiser .
I am not sure if what I am after requires the Edelbrook heads or not. I am going to guess by the time I price out a milling of heads and intake, guides and v-job. it will be not that far from new heads.
Time will tell.

olds 307 and 403

Yes, you can use the #8 heads. A clean up mill and either the old Speedpro flat top with 5/64"/5/64"/ 3/16" ring pack or the 1.3cc valve relief 1.5mm/1.5mm/3mm ring pack DSS forged pistons will give around 9 to 1 compression. There is an obvious lip under the exhaust valve. A bowl hog cutter when the valve job is done will open up the restriction. I used a die grinder to remove it, you would have to be careful not to hit the seat too much or a larger valve might be needed. They have 1.875" intake and 1.625" exhaust valve. They will flow the same supposedly as early 350 heads once that restriction is removed under the exhaust valve. Look at Kevin's442 350 build, it made over 400 hp and TQ with ported #8 heads. Good luck.