oringed block ??

getting started on a 1969 340 .040 418.

This block was ORINGED BY LAST OWNER and can i run it only with cometics ?Hard blocked also .

We are upping the compression to 13.5+ with head studs .4"callies dragonslayer stud main caps probe custom pistons .050 + out of deck, chevy rods , lite pins,MM rings change some top end oiling .Cam change stx22 cam from stx21 .same ported eddies as on 410 C.I Looking at 9.90s
thanks don

my 414 small block has o ringed decks , we run cometics with no problems , 12 to 1 with head studs & w5s

I have not ran one with Cometics with O ring grooves in block, but I have heard of multiple people doing it with success. I would just make sure you run proper size gasket so fire ring is seated on nice solid surface in between O ring groove & bore & should be OK.

Pistons .050" out of hole? Custom pistons? Just curious why you had custom pistons made to be .050" out of hole & what head gasket thickness you gonna run? After thinking about it, I'm guessing you're using open chamber 340 style E heads & that's reason for piston .050" out to get quench with the open chamber, I'd be real carefull to make sure that the chamber is bigger all way around than the bore of cylinder & take intake account piston rock..... assume nothing, measure everything. Bolt heads on bare block & look up from underneath to make sure piston will go into chambers & no parts of chambers are overhanging bore....If that is what you are doing, I'll just give my that it would have made slightly more power to run piston at zero deck & cut heads to make them closed chamber but that's just what I would have done, would make little more power/have better flame front/propagation & quench by making the heads closed chamber.

Sounds like should certainly make more power than it did before.

thanks guys
my eddys are the 6077 that had been cut .050 before i got them 2.08 ferra valves,ported.We sank and margined the valves last year to get cam back to 101 centerline as we had kb forged flat tops .The cometics gaskets .043 ?? The head looks like thiers about .055 left in chamber to shave i'll pass that thought on .Is thier a wider ring on a head gasket ?
thanks don

I thought the eddys were closed chamber?