What fuel octane do you use?

[RUNCHARGER]

I have first hand experience with it. The 906 heads on my truck had some exhaust valves pounded in 1/4". It ran just a bit smoother after I changed the heads out.

[Topcat]

Always the highest I can find.

That would be 91 unless I make a special trip over to grab 100 octane ethanol free gas. There is a station on the way to my office which carries all the Torco fuel lines.

Where Bryan?

[1 Wild R/T]

As I mentioned earlier in this post and as confirmed by Sheldon, Chryco Psycho is spot on.... You can quote all the printed articles you'd like I've personally dealt with valve seats pounded into the head....    And I've seen enough false statements posted in print that it doesn't mean a thing to me....  In many cases you can follow the advertising money as the cause for the statement, other times the author has an agenda.... Either way un-hardened valve seats will recede if used somewhat hard....

[Chryco Psycho]

Just because it is on the internet it has to be true right 
You can do what you want but 100% of the engines I build have hardened seats , I have seen many heads where the seats have eroded [not pounded in ] & A lot of them have never seen 6000 rpm in their life . The bonus is new seats can allow for bigger valves & even at stock height restore the seat height to as new rather than recessed , having the valves recessed hurts air flow . I can assure you no engine I will ever build with not have hardened seats installed .
Another factor is Mopar has always had more nickle in the the iron mix they use so the heads & blocks are harder but they still receed , also the last heads [452] on big blocks had flame hardened seats which hold up somewhat better but once you cut the seat for a valve job you are likely through the surface hardening .

[cudabob496]

I ran my 915 heads for 6 yrs without hardened seats, in my 440 Cuda, using 92 unleaded gas, and when I had them ported,
I was told the seats looked fine. So, everyone do what they think is best. I admit you guys have a lot more experience than I do.

[cudabob496]

As far as truth on the internet, we are all on the internet. I try to get my info from mechanics who post. The below is interesting. Alloys seem to be a big factor:

"Most of the early chevy motors I have done work on its important (having hardened valve seats) , as for the other Gm brands , never seen a problem , but like someone mentioned I think it had to do alot with the alloys used by the OEms , as Chevys alloys are like butter compaired to a Olds or Ponitac , and Ford and Mopar are like Diamond . the shop I use for my engine work loves working on Mopars and Fords as they can cut bores and not have problems like they do with Chevys , and I know a so called shop that complains if you bring them a non chevy block , they will charge you extra as its "hard on there tooling" they say , IMO they are a bunch of tools anyways over there . also several Oems started induction harden there seats in the late 60's , but I remember my grandfather and my dad talking about they used to valve jobs on there 40-50 era cars almost every 2-3 years when they had lead in the gas .
one of my Ponchos has 260K on it and was a unleaded car since the late 70's when they outlawed it here in Illinois , it was a daily driver apx 100 miles a day , in a old 72 bonneville , the heads have a little recession of the valves , one has micro welding of the valve itself , it still sealed ( 100 PSI) and ran when I pulled it out of the rusted out body .

[cudabob496]

At bottom of page, are additives that can replace lead yet help with valve seat recession.

http://www.classiccars4sale.net/classic-car-how-to-guides/restoration/a-guide-to-unleaded-additives

[HP_Cuda]

That would be the Sunol gas station just over the grade.

[cudabob496]

Red Line Lead Substitute

https://www.summitracing.com/parts/red-60202

[Topcat]

That would be the Sunol gas station just over the grade.

Yes I've gone there many times.

The only other one I know is in Saratoga.

[HP_Cuda]

You can actually drive you car up to Sonoma raceway (used to be Sears point) and fill up with all the CAM2 brands.

Not cheap though.

Cool thing is they are still running Grudge nights Mike - care to go next season?
https://www.sonomaraceway.com/track/wednesday_night_drags/

That would be the Sunol gas station just over the grade.

Yes I've gone there many times.

The only other one I know is in Saratoga.

[Brads70]

Careful with the race gas, unless your engine is built for it and requires it , you will go slower. A few gallons mixed with regular pump gas is ok.
But it does smell nice! Especially the Oxygenated Racing Fuels .... smells like perfume to me! 

[70/6chall]

Back when I was in the Navy ( Navy Air). My first duty station was NAS Pensacola Fla. I worked on the flight line, and of course had access to avgas. We could get the keys for the fuel pits from the night watch, a buddy, and  a friend had a '56 Chevy w/ a 283 in it. Of course military pay didn't make us millionaires so we'd go out to the flight line fill half the tank with avgas 115/145 and go into town fill up the rest of the way w/ regular. Chevy ran pretty good for awhile then a bit later didn't run at all, he tore the engine down in the hobby shop on base found that several of the pistons  had rather large holes in the tops of them. That stuff ran a little hot, wouldn't you say? He didn't even mention the plugs.         Thanks,   Al

[usraptor]

Here in Utah, the local Sinclair station has a pump that has 100 octane for $5 a gallon.  I run that in my 440/512 stroker '70 'Cuda and 87 in all my other engines.

[Bluemonster71RT]

My 383 runs decent on 93 but I have to retard the timing a few degrees.  When I have some extra $$$ I'll put some 110 in @$9.99 per gal. Ouch! It likes it a lot better performance wise at the slightly higher timing.