What was the mileage on your 300/6 when you rebuilt it and why??

 

My 300 got freshened up at 180,000 miles because of my stupidity. I pulled the 300 at 180,000 because the pan was leaking from the sides, due to rust through. I replaced it with a 302 because I wanted a V8. I wasn't happy with the V8, so I decided to freshen the 300. I tore it down to the bare block only to find it was like new on the inside, still has crosshatch in the cylinders. I replaced the gaskets, bearings, core plugs and rings anyway because I was there, and put the engine back in at 208,000 on the chassis. Sold the 302, and have been driving my 300 ever since. The 300 tends to average 17 MPG with my mix of driving... mostly about 14 in town and 20 on the highway. I have gotten as high as 22 MPG on the highway, and as low as 12 mpg on the highway with a 7,000 lb box trailer.

 

My 1987 300 was rebuilt in about 1993 by Jasper and has about 200 - 250k on it now, and I can get 18-22 MPG on the highway like Argo. (though my dad doesn't believe it)

I think most of that is due to the 3.08 Gears out back

 

I'll be quick to point out however that it doesn't like speed. If I even go 60 instead of 55, the mileage drops off fast. That's because of my short gears and no overdrive.

 

LOL i wish i know how fast i am going (Oversize Tires)

if i remember right im at about 2400 to 2600 RPM at the speed of traffic and the speed limits never go below 55. (its mostly 60-65)

 

What size are your tires?

 

31/10.50/R15's

 

You are about 7% faster than indicated. I.E. if you are reading 50 MPH, you are going about 53.5 MPH. To be safe from Johnny Law, I'd add 1 mph for every 10 on the speedo. For example, consider an indicated 10 mph to be 11 mph, or 15 mph as 16 mph. Consider an indicated 50 mph as 55 mph, or and indicated 65 MPH as 71 MPH, etc. For every 10 MPH, add 1.

 

wow i wish i had known that a long time ago

thing is a while ago i went by one of those things that tell you how fast ur goin in construction zones and the speedo said 45 and it said 54 or 56 MPH (cant remember exactly)

and my speedo wobbles about 3-4 mph all the time so its hard to get a reading anyway

 

You cvan't trust those construction zone radars, because they get out of calibration. The best thing to do to check your accuracy is to borrow someone's GPS (if you don't have one) and display your speed during a steady state cruise. That will be the most accurate method (down to 1/10th of a MPH). The wobble is likely a sticky speedo cable. You can remove it from the vehicle, pull the cable out of the housing, grease it up, and re-install it, or just replace it (they are pretty cheap).

 

Rebuild it?!?! only when it dies!!! If it does!! My first 6 I had I put in my 1966 (I know, wrong years, BUT same engine design) when I bought the engine, it had, according to the old farmers who I bought it from for $75, "oh bout 150 meybe hunert sebenty five or so,,,,don't rightly recall" he had the head done, "just a bit ago" so I went with 150k as a starting point. I drove the living crap out of that poor engine for the last year and half of high school, 6 years of the Marines, ang I gues it had another 150k or more on it when we bought our house, and the wife said, "it is NOT going to our house" so I junked the truck, the body was rusted and beat, but that stupid engine would not die. I actually ran it without oil, still wouldn't die, drained the antifreeze, STILL running for about 30 min, when the wife came out said it was time to go to dinner at our friends. I put the fluids back in, junkyard guy came the next day, asks "does she run?" she started right up and purred, he said, good, I need a new engine for a wrecker at the yard!! Far as I know, that thing could still be running!!

 

Thanks for the info
I Have a GPS but its on my phone and doesnt tell speed, but I think i know someone who has one.
I figured the speedo cable was bad (since i already replaced the head) but im gonna get an autometer adjustable speedo with and electric sending unit.

 

Thats a sweet story on the toughness of the ol 4.9L Would it be possible to check and see if it is still goin?
Shame they discontinued them

Makes me wonder what my dad did to that 300 in the 87 (2nd one in sig) to make it NEED a rebuild at 200-250k (started to smoke pretty bad)
Oh and I know he kept it up in basic maintenance

 

If I could I'd rebuild mine right now. Still runs good, starts good, 16 mpg highway, doesn't burn or leak any oil, oil pressure is good. But at 217,000 miles she isn't feeling like she used to. I'd really like to just rebuild the whole engine. The injectors need cleaned, I'm sure it needs a valve job.

But, the engine doesn't NEED rebuilt yet, but it would be nice.

 

well, mine had 305k and change and when i junked it i was still pullin trees and stumps and cars with it. never smoked or burned oil. it still was powerful and still got 18mpg with a semi heavy foot. and i had 31/10.5 R15s with 3.08 gears and a M5OD. i expected at least 50k still left in it. if not more.