225 slant rebuild for more power

Thi
Pull the head, Mill it .100 thousands if it has never been touched, that will get you to 9:1 area But measure piston deck height to get in the ball park and cc heads,

clean up the head while you are at it carbide bit off amazon less than 20 bucks port it out a bit just smooth out any casting flaws dont go crazy add 340 springs,

get some split exhaust manifold or run a 2.25 exhaust head pipe under you stock manifold

recurve that distributor swap over to electronic ignition

super six it but get ready to redo the whole linkage and kick down also need a early v8 gas pedal assembly

Send your camshaft to oregon Cams get a regrind or pick out something for torque cause you got a heavy car.

Should have a nice cruiser while maintaining MPG and adding HP[/QUOT
Welcome to the club.
I completely rebuilt the 225 in my 64 Val because it was locked up when I got it. Following recommendations here I did the following:

Milled head 0.080 but you should consider going 0.100. As Charlie says, no downside, big upside. Modern head gaskets are at least 2X thicker than the original steel shim gasket so you'll lose a little compression. I did a complete rebuild do had my machinist install hardened exhaust seats with valve job. I did a little pocket porting and gasket match because it was only my labor, free!
Block bored .040 over with Silv-o-lite pistons and moly rings.

Sent the cam to Oregon Cam grinders to be reground. Talked to the owner and he recommended 2 grinds and I went with the milder because it's a driver. I'd say it's between 318 and 340 specs.

Did a little porting on the stock exhaust manifold and gasket matched, free labor.

Rebuilt the stock BBC carb. Advance timing to 10* BTDC.

Anyway, it drives great. Never feel a need for more when driving. Best ET was 18.4 secs. Got almost 24 MPG going to Carlisle. Have about 8000 miles on it and haven't touched it.

You can do less and be fine. Since you are taking classes, disassemble completely, new timing chain, maybe hone and re-ring, check bearings, oil pump, etc. and inspect everything. Dyno proven that biggest increase in power is going to 2 barrel carb.

You need to read this section and check out slantsix.org
Disregard the haters who say V-8.
Alright couldn’t have asked for a better explanation from you guys. I have a daily truck so I’m in no rush to get this motor going. I’m gonna take it apart and get all the measurements this week It is %100 stock numbers matching which is another reason why I don’t want to put a v8. I do have ac but I couldn’t give a hoot if i don’t have it. Will use my Christmas money to send it to a machine shop. Anybody know any machine shops in CA that will do this. Thanks guys so cool hearing your guys thoughts more helo than I could imagine