5, 6, & 7 heads are only subtly different and would only notice the difference on a dyno. All good heads with a proper three angle valve job that includes hardened seats. Good luck. By the way, some people just recommend going the aluminum route but I think that the iron heads still work out to be a lot cheaper.
Olds 350, (does these numbers make sense) WHAT YEAR???
- Thread starter Pharozen
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foxtrot said:
If you are rebuilding the engine and are planning on replacing your pistons with something other than factory dish, aluminum heads are the way to go. Procomp makes the best aluminum Olds head for the money and will out flow any factory casting in stock form. As noted above, the chamber size on some of the early factory heads are similar but flow bench studies have supposedly shown that #5 heads are the best flowing factory head in stock form. I paid dearly for a set to put on my 403 and then stuck another $1K into them for SS oversized valves, 3 angle grind and port work. This made sense for me because my 403 has forged TRW's with the factory dish (I needed the small chamber to obtain a respectable compression ratio). When I build another Olds motor, it will get Procomps or Edelbrock heads.
I got pro comps on my 455 and in my case it was cheaper to buy them than to modify a set of cast heads for what I was doing but 5 6.or 7 there all pretty decent SBO heads don't 7's have induction hardened exhaust seats or is that just 7a's
From the Mondello Olds reference book
Block #395558 2 is a 1968-1976 350 Block
#7 heads are from 1971 and 1972 and are casting #409147.
In original form the specs are;
The 1972 heads are ok for unleaded fuel
The 1971 aren't.
1.875 intake valves
1.562 exhaust valves
69cc chambers
Block #395558 2 is a 1968-1976 350 Block
#7 heads are from 1971 and 1972 and are casting #409147.
In original form the specs are;
The 1972 heads are ok for unleaded fuel
The 1971 aren't.
1.875 intake valves
1.562 exhaust valves
69cc chambers
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