Another person with cylinder head questions

I have a 69 GTO and am curious if my heads are worth rebuilding.  The info I have is as follows:

The engine is not original but the heads I believe are.

Head date L048 code 62
Cylinder Head Date L048 represents the cast date for the head: L=December 04, 1968. The 62 on the exhaust ports represent 1968, 400 CID, 333-350-360 HP motors. This is located on the driver's side cylinder head beneath the valve cover.

I would like to have a nice driver car when it is done and don’t have the money for edelbrock heads.  I do have time on my side to shop around for better heads if needed.  I’ve read a good bit of the posts on here about 6x-4 heads but, I don’t know if it is necessary.

My motor, I believe, is out of a Pontiac Grand Prix.  It is a 9790071 with date code I068 and there is an XH on the front of the motor just beneath the passenger side cylinder head just above that there is a number 104479 (not sure what that means).    Engine VIN 29P119357. Breaks down as 2=Pontiac 9=for use in 1969 model year P=assembled in Pontiac, MI 1=first 100000 units 19357=serial number. Located Just to the left of the timing cover on the front of the block.  This obviously does not match my GTO VIN.

Anyway, input on what I’ve got and where I should go from here would be nice.  Again, it’s not a race car but I would like power for the street.  

The number 62 heads are good heads and are capable of making a decent amount of power the only problem is they will give you a 10:1CR on a 400 with flat top pistons and that is too high for a pump gas engine regaurdless of what some people might tell you yes you can turn the timing down so it wont have detenation and you will think you are getting away with it but you aren't because it will eventually cause damage to the piston, rings, and bearings.  
professional hi-performance engine builder

Horsepower sells engines and torque wins races

You could reuse the no.62's if you're rebuilding the shortblock- get some dished pistons and that should lower the CR to 9-9.5:1 (depending on the cc of the dish), enough to run 91 octane pump gas. If you're only looking to refresh the top end you may want to consider 6x's. The 6x-4's have a 94cc combustion chamber, which yield a more pump-gas friendly 8.5-8.6:1 (87-89 octane w/ proper tuning).

Whichever heads you use I'd recommend upgrading to stainless 1-piece valves, as the 30+ year-old 2-piece valves can fail and destroy your engine (lost a 350 when it sucked a valve, cracking the head and block).

Geno  

Thank you both for your input.  Is it possible to open up the combustion chamber on the #62?  If I have the heads worked on for instance; valve job, ported, polished, etc. would it make sence to open up the combustion chamber as well?  How much money is too much?

Also, if I kept a bone stock setup wouldn't I have 10.75:1 CR?  What do enthusiast do in this circumstance?

Thanks for the quick replies and the great input.
Steve  

Yes- it's very possible to open up the combustion chambers to lower compression, but whoever does it needs to know what they're doing (no Chevy porters!) I have a set of ported no. 13's and no.48's that were 72cc heads like your no.62's, but in addition to bowl and port work I opened up the chambers to around 82cc, yielding around 9.5:1. My chamber work is similar to what is described in Jim Hand's "Max Performance Pontiac" book (smoothed all sharp edges, rolled back the valve shrouding). I also cc'd both sets of heads to verify actual volume.

Both heads run very well- w/ a crane 284H cam, Holley 750 v/s on e-performer, and w/ Hooker comps and 2 1/2" duals on a 406, my 'Bird runs consistent 13.0x's w/ a 3.08 posi in street trim.

Geno  

The 10.75:1CR is what they say it had from the factory but the factory rating is about .50 higher then the actual C.R.  
professional hi-performance engine builder

Horsepower sells engines and torque wins races