I have enough experience with my truck at this point to make my own judgements, but I want some other opinions as well.

3 weeks ago my primary car was mothballed and for the second time my '56 F100 became my daily driver. Here's a brief history:
Engine rebuilt 2009, truck on the road by 2010.
Truck was daily driven--it was my only car--from early 2011, to June of 2012, then sat and was rarely driven until about a year ago when I fixed a leaky gas tank, rebuilt the carb(again), etc.

As of 2012 (at some point) the odometer broke, in fact the whole speedo broke first, then the odo broke later; at the point it broke, it showed I had logged 9000 miles. As of today, I estimate truck has 11-13,000 miles since revival. She looks the same as she did in 1990, old, beat to ******, tried-and-true.

But now that I am on my second running with this truck I recollect that the first time around I rarely ran the engine past 2700 rpm. In recent months--before and after it became my primary--I find myself regularly running her to 3000 rpm and no higher which puts me at 60mph. It seems to handle it well.

Do ya'll think this engine is meant for this kind of rpm, regularly? This truck will most likely be my primary for at least another 8-10 months. I need to know if I'm askin' too much of her, or if it isn't a problem.


I can proudly say I am one of the few that really gets to experience and enjoy their truck, even if it isn't very good looking.

 

If runs good at 3000 and you still have good torque the engine is fine. The only killers would be heat and low oil pressure. My father used an in line 6 cyl in his saw mill. It ran all day long for years. That's the rpm he ran it at.

 

Isn't 3,000 r/m a little close to the stock red line?

 

The 6's were rated for max HP at 3500, redline would be in the 5's. 3k won't hurt it, no one gave a second thought back in the day. I wouldn't worry about it, as long as maintenance is kept up.

 

Well that sounds encouraging. A I6 to power a saw?!? DAMN. Sounds incredible.
I need a new ODO now, getting tired of guessing mileage and maintenance.

Thanks for the advice everyone.

 

My opinion, 3000 RPM for extended time periods is a little too high. I'm more comfortable in the 2000 to 2500 PRM for that situation.

 

I saw a similar thread on ford barn on that's what it seemed to suggest also. My 226 seems pretty happy around 2300 which is about 50mph.

 

I ran a 272 y block for 3800-4000 rpms for 500 miles and never used a quart of oil! in my f600 with 6.88 gears

that 223 will be just fine at 3000

 

Your profile says your 56 has a 3.92 axle. Either you have some short tires or you're going more than 60 at 3,000.

 

I put 275/60-15 on the rear when I first got it going and remember having some "pinging" detonation issues during the first round of daily driving. I felt like the engine was already lugging, and resetting the timing and using higher octane fuels were not helping. (Both the engine builder and two other engine shops in town insisted that for my stock engine specs to which it was built, I would never need anything more than 87 octane. PERIOD)

This "pinging" problem was the main reason why I never used that T-86 OD that I bought 6 freakin years ago that some of you may remember me going on about. (It still collects dust in an old garage somewhere)
..and this is also why I never bothered putting larger diameter tires on the rear to help my speed.

As of recently, the pinging is rare and minimal. Not sure why that is, but I pay close attention, and very rarely hear it.
Spending $300 on new larger tires and immediately realizing it's too much for the old girl is just too bitter for me to risk....but it may happen soon, need new tires.


I have an app on my phone that measures speed and I have tested it in 3 cars, and appears to be reasonably accurate. The fourth car I used it in was my '56 and it says 60mph on-the-dot when my tack says 3000. So that's all I can do to guess my speeds.

 

With a 3.92 gear it's probably at 3000 RPM at 60 MPH. Mine originally had a 3.92 gear. Only had it on the freeway once. With a 275 rear tire, at 60 MPH the tach was at 3000 RPM. I slowed down. I didn't want the 390 motor to rev continuous at that RPM.


Pinging: Could be many things, spark plug heat range too high, A/F mixture too lean, engine temps a little too high, timing too advanced because of too much mechanical or vacuum advance. Many times reducing or eliminating the vacuum advance will stop the pinging. Have you tried eliminating the vacuum advance and see if there is a difference? If you haven't already, do some research on Quench Area. This is the area above the piston at TDC and has a large effect on controlling pinging. I know with any type of performance engine, proper Quench is one goal during the engine build. I know it's a 6 cylinder motor, but what compression ratio does it have?

 

Pinging is not normal. You need to find the cause. 87 octane fuel should be enough. Depending upon how bad it is you can easily burn a valve or a hole in a piston.

I would check for a vacuum leak leaning out your mixture. This assumes that all the other items mentioned above are normal. Another trick is to add a phenolic spacer under your carb. What temp thermostat are you running? It should be 160 degF I think (others on here can confirm or correct). If you are running too hot a thermostat at that moderate RPM that could also contribute to your ping.

 

True. Worst case I've seen is the top of a piston break off. I guess it range from mild and annoying to catastrophic.

 

It could also just have been built-up carbon that has since burned off with regular use.

 

I tried hunting down this issue years ago and got basically nowhere at the time...only with time did I notice that the pinging really went away for the most part. The factory spec thermostat is 195º I believe, from what I've read in other threads. However I'm running either a 160 or 180º.

The vacuum advance: One of the reasons the engine was overheating when I broke it in was because it wasn't hooked up. This engine has only run better with it in my experience. Time is set at factory 5º BTDC.

Carb spacer is in place. Mixture screw was installed by a Holley 1904/1908/1960 pro by the name of M. Mayben, Just do a google search, he used to be around and was very well known for his knowledge on these carbs. The carbs that came factory on these 223's were actually Holley Model 1960's, not 1904's as some are led to believe.

As of today, the pinging only happens when I'm headed up a semi-steep grade and really give it the beans. I tested it just a week ago to see what it'd take and it started pinging at 1/2 or more throttle @ ~2300rpm. The grade was probably 3-4%, and continuous. The truck was running otherwise very well, and by the time I had it at 2800(still on a constant climb), there were no signs of pinging, she was still accelerating very well and handling it well overall.

If I give it the beans on a flat surface, it will typically not ping unless I REALLY give it to 'er(we're talking >3/4 throttle). And that never happens, I have no reason to drive like that. I only know this from testing it every 6-8 months or so to see if it's running consistently.

So far this truck is very sound. I will be tire shopping in the next month....and I might go bigger in the rear.