66 Olds Heads

[SupremeSpeed]

Just as the title says. I saw an ad posted, and I was drawn to this item. Now I've never heard of #3 heads personally, and thought the Olds #5 were the best, or most sought after heads. After seeing these, I did some Google research, and now arrangements are being made to buy them. I just wanted to see what you guys thought about these heads.

 

[HOAdrian]

Valve sizes are the same on #3 and #5 heads unless you're talking about the W-31 heads with bigger valves. I know the #5 heads can be upgraded to the bigger valves so the #3 heads can probably be increased as well. My understanding regarding the installation of hardened exhaust valve seats is shallower seats are required to avoid cutting into the water jacket. IMO hardened seats are not really needed for a street driven can that is not going to see a lot of sustained high-RPM use. Some of the early Olds heads used valve rotators. Not sure if the #3 falls into that group.

Combustion chambers a little bit smaller on the #3. No idea how the ports compare, but I suspect they are close. I think the #5, #6, and #7 small block heads are the most sought after because they were available with larger valves in the W-31 and on the 39 degree cam bank angle 350s. You may need to open up the push rod holes for clearance.

What engine are you planning to put these on? I have a 403 with #5 heads in a wagon that runs great.

 

[olds307 and 403]

They are very similar to a #5 head, no unique valve train parts like #1 and #2 heads. The chamber CC and flow numbers would be very close to each other as well. If the price is right, grab them. The only real difference is the push rod holes may need enlarging due to the 45 degree cam bank angle.

 

[SupremeSpeed]

Valve sizes are the same on #3 and #5 heads unless you're talking about the W-31 heads with bigger valves. I know the #5 heads can be upgraded to the bigger valves so the #3 heads can probably be increased as well. My understanding regarding the installation of hardened exhaust valve seats is shallower seats are required to avoid cutting into the water jacket. IMO hardened seats are not really needed for a street driven can that is not going to see a lot of sustained high-RPM use. Some of the early Olds heads used valve rotators. Not sure if the #3 falls into that group.

Combustion chambers a little bit smaller on the #3. No idea how the ports compare, but I suspect they are close. I think the #5, #6, and #7 small block heads are the most sought after because they were available with larger valves in the W-31 and on the 39 degree cam bank angle 350s. You may need to open up the push rod holes for clearance.

What engine are you planning to put these on? I have a 403 with #5 heads in a wagon that runs great.

I have an Olds 350 but I also have a set of #5. I got them for a good deal and figured I can use them in the future. Thank you for the info as well.

 

[SupremeSpeed]

They are very similar to a #5 head, no unique valve train parts like #1 and #2 heads. The chamber CC and flow numbers would be very close to each other as well. If the price is right, gra them. The only real difference is the push rod holes may need enlarging due to the 45 degree cam bank angle.

I got the heads on a swap. He needed a BOP TH400 and I happened to have one.