Are these decent small block heads?

[Midwestblue]

HEAD CASTING #'S

Here are all the casting numbers, and what I think they were used on. Would these be good heads to use for a 9 to 1 compression, fairly mild motor, around 300-325 horsepower?
GM 11

3973487...used on 71-72 350 LT1, 75cc chamber

 

[bluebomber]

those are pretty good heads i think 75cc chambers port volume is good too. for a whole listing of chevy castings numbers go to www.thedirtforum.com and find the tool box it has a list of a bunch with specs

 

[POWERMAD]

I have a set of those in the shed.
This is what I came up with them.

1971 Z28 Engine - LT1 330hp (gross, 275hp NET) Casting # GM P/N Description
Block 3970010 4 bolt main, suffix codes: CGP, CGR
Crankshaft 330550 Forged steel
Heads 3973487 75.47 cc, 2.02/1.6 valves, screw in studs & guide plates
Cam 3972182 3972178 symbol: (1) square Solid lifter - 0.458(I)/0.484(E) lift, 317I/346E duration
Pistons Flat w/valve relief - yields 9.0:1 compression
Intake 3959594
Carb (A/T) 3989022 Holley List 4800, 780cfm , 4150 series - 4BBL
Carb (M/T) 3989021 Holley List 4801, 780cfm , 4150 series - 4BBL
LH Exhaust 3989041 Rear exit, log type w/AIR, 2.026 outlet
RH Exhaust 3986330 Rear exit, log type w/AIR, 1.96 outlet
Distributor 1112049 Manual Trans, RFI, single point w/vacuum
Distributor 1112074 Auto Trans, RFI, single point w/vacuum
Alternator: Delcotron 37 Amp, part # 1100837
Water Pump: 3957170

Cylinder head has swirl polished valves and chrome valve stems.
Alternate cylinder head was 3986316 (unverified).

It seems it was a decent head back in the day.