can stainless steel valves be used in my 2000 500hp carb motor /my michine shop is recommending them///intack&exhost

I believe you'll find that they're the only kind you should use- Extreme Duty SS Intake Valves and Iconol SS Exhaust Valves

If they are using Manly valves, then use the Severe Duty Intake valves(Stainless) and Extreme Duty exhaust valves(Inconnel). Be ready for the price. The ED's are about $40 each and SD's are about $25 each.

what about the stock 500 hp exaustvalves what are they //if i use Inconnel should I change the exhaust seats

The exhaust valves on the 500hp was a manley and it's the best thing out there for the money it's hard springing for the price but well worth it watch parts guys selling you a valve for less money in the valve trane department you get what you pay for there is a bunch of crap on the market that looks pretty and isn't worth a dam. Best of luck Sincerely Laz Mesa
www.mesaracingengines.com

You do not have to change the seats.

If you have a gm cylinder head with the hardened seat as comes std equipment in all late model gen 5 and 6 you do not have to change the seats matter of fact thats the valves used in the 500 hp blue engines from factory. Check valve to guide clearance and assemble if good remove the spring from the exhaust valve seal if the clearance is good and expect 180 to 250 hours of duty . Also make sure you use a good quality spring such as Iski crane comp with the correct press for you application. Good Luck Laz Mesa
www.mesaracingengines.com

thanks 4 the help//they are gen 6