Cool! I'm jealous.

 

Hey man I'm going to get my dad to take those pictures for you sometime this weekend so keep and eye on your email and we will figure it all out man.

Take care

 

so, let's talk about RPM's at cruising speed for a moment. Clyde now has a tach, and i was surprised, when i got to 70 mph cruising speed, the engine was at 2200 rpms. i was expecting closer to 3 grand. for those not reading the first post, Clyde has a 300 straight six, C6 trans, and a 9" with unknown gearing. the truck rolls on 235/75R15's (29 inch tall tires) and is a 2wd. i am chasing mileage, and have considered swapping to an overdrive trans (possibly a manual overdrive), but seeing the 2200 rpm cruise speed, im wondering if just the overdrive is going to hurt me. dare i consider an overdrive AND a rear gear swap? thoughts? ideas? anything??

 

What speeds do you normally drive? These trucks aren't as aerodynamic as a brick since their grills are not flush with the front of the hood - something that was changed in '87. At 70 MPH there is a big, big difference in drag vs even 65 MPH. My engine, with 3/50 gears and the ZF5's OD, is only turning 2K at 65 MPH and I can get about 14.5 MPG there. But push it to 70 and it'll drop into the high 13's.

As for the rear gear, I'm guessing you have 2.73's. I get there by multiplying the ZF's OD ratio of .76 x my gear ratio of 3.50, getting 2.66 - which wasn't a valid ratio IIRC. But it sounds like you are geared about like I am overall, and we are running about the same sized tires. I don't think I'd go to an OD tran if I were you w/o changing the rear axle ratio as I think you are in the 300's sweet spot.

You need to confirm the axle ratio though. You may have the tach in 8 cylinder mode.

 

no, i am certain i switched that tach to the 6 cyl spot... but i knew that would come up. i will verify it again, just for you, Gary.

i know my last truck "the farm truck", was an 87 f150, with a 300, SROD 4 gear, and 3.55's, on the same tires, and i was pushing into the 20mpg mark. my 95, with 300, M5OD, and 3.55's got a best of 23 after i got it lowered enough.

My driving habits are as follows: 6 days a week, i drive an 11 mile one way commute, usually i take the 4 lane on the way there (70 mph) and the blacktop on the way home (55 mph). once a week i take a 100-ish mile trip (70 mph) to go hunt vintage Nintendo games in one of the nearby cities. and sometimes the truck may be subjected to running all the way to my sister's place and back (700 mile trip, all 70 mph). so yeah, mileage does become a key factor.

i realize aerodynamics are not in my favor, as the 87 and 92 both had improvements there. however, i dig the style, i dig the simplicity, and i'm hoping that the lighter weight will help me out a bit. Also, i still have a set of Lightning front springs, and whenever i locate all the parts to put 1995 front beams/spindles under the truck (for caster/camber adjust ability, and better brake caliper mounting), i plan on dropping the truck down about 2 inches, with proper swaybars front and rear, to both increase stability, and hopefully, cut down a little wind resistance.

 

You are in rarified atmosphere on your MPG with full-sized trucks. Good job! But dropping it down will help, as will a chin spoiler. Look at how the spoilers have evolved - our trucks were the first to have them at all, and very few recall ever having seen one. The next series had them on most trucks, but they were still fairly small. After that they got big and came on all the trucks. So, there must be something to keeping the air out from under the vehicle.

 

i take pride in chasing mileage... even on the crappy 87 octane, 20% ethanol thats in every pump in Iowa now. it's simple math, really, more aerodynamics, better airflow in and out of the engine, and keeping the truck mechanically sound.

i've never seen a spoiler on an 80-86... may have to investigate. my 87 and 95 did not/do not run a front spoiler, however, i noticed gains in lowering, and in installing a tonneau cover.

 

20% ethanol? wow! that's disgusting. I thought 10% was bad enough here.

 

20% and my vehicle won't run. I have a hard enough time with both 10 and 15 around here just in my lawn mower.

 

All of my small engine equipment never have problems with 10% 89 octane. They even sit all winter with the gas. The ole push mower usually starts on the first pull after sitting all winter. Just like it has the majority of the time for the last 36 years lol.

 

I had a good mower that lasted a long time to the point I couldn't get a deck for it anymore. When that deck went I couldn't replace it, so it was time for a new one. 2 uses and the float bowl got stuck and it takes about 45 seconds to a minute of cranking it over continuously to start it. Pile of crap. Gas is crappy here. Luckily the local Indian reservations sell ethanol free gas. It helps but its still not that great. I had problems with my Dodge van for a while because of IMO s****y gas. The lowest grade here is 87, but I've seen it up to 93 or so. Truck used to run 117 octane back in the 90s. Don't wanna know how much that costs now lol

 

It would be nice if they still sold the high octane leaded fuel. I know what you mean about the deck thing. I had to find a different mower completely for the old engine. Which worked out great because I needed a replacement engine for another mower and a replacement deck for this one. I restored're painted the deck, put steel ball bearing wheels and nice height adjusters on. Made it look mostly like how it was originally. The thing I find cool is the engine has over 1100 hours on it now and the inside is like a brand new engine yet. Only thing not original inside is the sump cover gasket, valve cover gasket and bottom oil seal. In fact it has so many hours on it that when I took it apart the cavity in the cylinder head was filled flush with carbon. Guess that was from the 5 gallons of outboard boat gas my dad ran through it in the 80's or 90's. Wow I just told the life story of my mower there. Oh well LOL.

 

Once the deck broke on mine I tore it down and scrapped the frame and wheels and donated the engine to my school so the students could tear it down and learn etc. at that point I was still in school. The mower was like from the early 80s I think. Was a great mower but like I said the deck went bad. Honestly I'm surprised it lasted so long. The thing as a whole ran better 30 years old than the brand new one I bought. I was pissed.

 

I tried to replace that lawnmower. And the new mower was such a piece of **** that I had to resort to using the old mower again. Never fails the old 3.5 HP Briggs starts first pull every time unlike that new mower which I sold. At this point, I wouldn't be surprised if this engine outlasts us all. It doesn't even require a top off between oil changes the majority of the time. And the original piston rings are in the engine now and they have been off the piston.

 

My old one was a key start with a 12 horse motor. The new one claims 20hp or something it i feel that's bull. I have a 20 horsepower Honda 200X. I know that that feels like and its not even close. Feels like my 6hp yerf dog go cart lol.