Thanks guys for the complements!! One other question I have about the car. When I start it up a cloud of white smoke. Did I add to much additive because it only did it after I put gas in it and added some?
The '73 block is fine as is and emissions related items were not in the block.
noted, the combustion chambers in the head as measured in CC's, is for the most part how Pontiac lowered compression. So compression was lowered using bigger chamber heads. Also, valve size determines some of that HP. Typically the 2.11" larger intake valve size are used on the higher HP engines, and if your heads are the 1968 #16
heads, you have the good heads. HOWEVER, there is also a small valve #16
head used in 1970, so you want to confirm they have screw-in studs and check the cast date code. And of course, camshaft size provided the HP ratings.
So the answer to your question is "yes", this all adds up to better HP, closer to stock or possibly a touch more with the #16
heads UNLESS the rebuild included pistons that were installed to reduce compression with the #16
heads so you can use pump gas without detonation/pinging.
Keep in mind that in 1971, HP/Torque ratings went from "Gross numbers" to "Net numbers" so the HP/TQ numbers appear to have really dropped, but not so much as you might think. The change in how the HP/TQ was measured is what causes this radical drop.
The smoke could be from the additive if it has oils in it OR the valve seals may be going south on you. Typically when the car sits a bit and then when you fire it up you get some smoke, it can mean valve seals. But since your engine was rebuilt 7,000 miles ago, it should not be the oil seals. So just monitor it and watch the next tank of gas.