stainless steel valves

i got a 59 chrysler, with a 383. are stainless steeel valves really needed for todays type of gasolines?

OEM quality valves with chrome stems will do just fine, from what I've seen. The reason that Buick went an extra year before induction hardened valve seats on their engines was their nickel plated valves. As long as there's no valve rotators (as Olds proudly used for years), the valves won't turn that much and accelerate the erosion of the valve seat (due to the rotation).

Key thing is to have valve guides in good condition to keep the valves square in their holes as they seat. I personally like the bronze heli-coil style valve guide inserts as they are supposed to be an excellent wear interface for chrome stem valves as Chrysler used, plus they are easily replaced should that be needed (just pull the worn ones out and thread the new ones in and seat them in the groove). There is also a orange silicone valve seal that Chevy 454s used that fit the Chrysler valve stems. Trim them a little on the bottom and they work great, but now you can probably get the Chrysler-spec ones in silicone too.

If there's real concern about valve seat issues, then pay the extra money and get the hardened seat inserts put in the head by a competent machine shop. But considering that in a Chrysler test circa 1973, they took a 440 engined wagon with the full trailer package, loaded it to full rated weight, and then ran it at the proving grounds under full power/full load until the heads were junk from valve seat erosion. That took about 12,000 miles in those conditions. Normal driving is MUCH LESS demanding so you can lengthen that mileage several times before any problems might arise.

The other issue is that numerous valve jobs will end up sinking the valve seat too far into the port. In that situation, the best solution is either new heads (from Chrylser's Mopar Performance program?) or valve seat inserts (as mentioned earlier). With the newer heads, you might need the later style valve covers too.

I really don't see the need for stainless valves in any kind of normal street motor, even if they are "high end" parts.

Just some thoughts,

NTX5467