Technical SBC heads non harden seat's will they work or not

SBC power Pac heads redone on my shelf--non harden seats will go on a 327 engine-- will be used 400 - 500 miles a year---will this work with today's gas or will it get damaged in a short time-- Thanks

 

I believe there is an additive you can use to help it.

 

I call bullshit myself, but like he said, you can run lead substitute. If you were running in a Nascar race it might be an issue, but I've ran double humps without them for years, and the power pack heads on my El Camino have the original seats.

 

Run it. It’s not your going racing.

 

I’ve put probably a a couple hundred thousand miles on non hardened seats.
No additives.
If it’s a dump/log truck, I’d put hardened seats.

 

Why only 400-500 miles a year?
That’s a good weekend number
What’s the purpose of not driving it?

 

I think it depends on how hard you work the engine. The 302 Ford in my ‘55 F100 sank the valves 1/8” after a few years. I moved 400 miles away and made several trips using it to pull the trailer hauling my tools, machines and cars. The heads were junk, but I worked it pretty hard.
You will probably be ok in a hot rod that doesn’t work that hard.

 

I’ve had em installed. Wasn’t much at all.

 

I've seen the machine shop only change the exhaust seat, does that make any sense? The intake seat doesn't see any heat? Hmmmmm.... I did have the seats changed in one set of heads a couple of years ago, they cut them for bigger valves, but I feel like it was a waste of money lol

 

The machine shop I use told me that non hardened seats and valves re good for about 30,000 miles with unleaded gas.

 

Exhaust is the only ones I’ve ever had done.
Only because of it going in my bus

 

At only 500 miles a year that’s good for 60 years.

 

Yeah I've seen it lots of times, I just feel like the chamber is a heat sink and the intake seat is seeing high temperatures also

 

The engine You described, Will with Out question do everything intended, An a Good "cleaning out" You'll never have a problem.

 

The intake side is cooled by the fuel
I’d like to see the temp difference between the 2 just out of curiosity

 

I'd bet there's 4-500 degrees difference. Lippy

 

Well, I've been running freshened up 1970 351W in my coupe now for approx 46000 miles. Replaced a couple of valves with used ones, and did the seat angles at the time of re-freshening. Remember the machine shop telling me I could go without the hardened seats. (That was in 1995!) Haven't noticed any thing wrong with the way it runs, although it may be because I've been driving it over a long period.

 

I have yet to need hardened seats in any of my Small Blocks. Valve seat recession is usually a result of high RPM, High heat/load. a typical Street Machine will not encounter those conditions. I do have a set of 186 heads that need new Valve seats, but the damage was done due to bad valve guides per my Machinest.

 

Hardened seats make machine shops money in most cases. If you occasionally add a few gals of race fuel there's enough lead in it to cover your efforts for many years to come. Add 1 or 2 gallons once a year. Or if you can get old school AV gas that works too. I'm just not a fan of snake oil substitutes.

 

Might depend on the engine and how it's run. I once found a NOS head for an off topic engine that had non hardened seats. Didn't want to run it because I had my doubts it would last, but was told no biggie. It lasted about ten thousand miles (not very long) before the seats were hammered. I had hardened seats installed and drove it another thirty thousand miles before selling it. Soft seats didn't work out for me.

 

I too think it’s the heat from exhaust is why they use them. The 218 I have came from a ‘49 Plymouth, I refaced the seats by hand, the exhaust was definitely harder than the intake seats. But I have no idea if the seats had been changed in the 70 years prior.

 

I have yet to put hardened seats in anything and I put thousands of miles a year on my junk. Another one of those things that no one has told my old cars doesn’t work.

 

I never don't have them installed.

 

if you live in an aera where E15 is taking over it wouldn't hurt to have them installed

 

A machine shop is going to want to make sure that there will be no issues for them to have to cover, and you can't blame them for that. However, I am also running stuff on unleaded fuel without any problem. If you want the absolute best, go with hardened seats. If you're building something that is never going anywhere but the car show or parade, I wouldn't worry about it. 500 miles a year? I would see how it runs before tearing into anything. I wonder how many engines are out there, installed, with high dollar rebuilds, that won't even start and run do to just-sitting-there-in-the-garage issues.

 

We didn't bother on the 283 in our 57.
But we sometimes blend all the old leaded race-gas from our race car. [why waste it?]
Our 4 stroke line trimmer and Lawnmower also runs on this as well

If you're only doing 400-500 miles per year that is only 36 gals [at 14 mpg]
Just buy 12 gals of leaded Avgas and blend it 3:1

If the Avgas cost an extra $3 gal more than regular ,it would only add an extra $36 year.

 

I would say your machine shop is right on the money. I had non-hardened seats in my daily driver a number of years back. It had a '70 vintage LT-1 short block with large chambered heads (to reduce compression)...got about 25-30k miles on it before it started running like crap. All good, except when the failure occurred we were a few hundred miles from home on the highway. It was running REAL bad by the time we rolled into the driveway! A couple of the exhaust valves had sunk in the seats.

So at 500 miles/yr...you're good 'til 2083.

 

I'm in the why bother camp
Not putting enough miles on it to justify the need.

 

Don't bother...I had hardened seats put in some otherwise fine turbo heads, managed to cause a coolant leak from behind them into the chamber. Wish I left them alone, could have saved a bunch of money and work.

 

Thanks for all you help and Advice -- will put that money towards my Mustang II
suspension