K5 Blazer?

[cRiPpLe_rOoStEr]

I'd also get a Diesel one, either the 6.2L or the 6.5L which is still being made, altough more targeted to military and marine applications. One simple mod I'd consider is to replace the engine-driven radiator fan with a thermostatically-controlled electric one, which is cheap and very effective since it allows the engine to warm-up quicker and takes less engine power to operate. Replacing some body panels such as doors, tailgate, hood, front fenders and fascia with lighter ones made out of fiberglass (eventually could consider a single-piece front clip since it wouldn't have gaps between the hood and fenders) is a good measure to consider too. Replacing the TH400/3L80 transmission with an overdrive 4L80-E could be also considered if you wouldn't mind an electronically-controlled transmission.

If you would go the gasser route, could take a look into some LS-series engine, even the 4.8L V8 would already provide some good performance, and then you could also take a look at the newer 6-speed transmissions...

[larrybuck]

I have an '85 K10 Suburban with 6.2 with MANUAL aftermarket hubs.
With smallish street (all weather tread) tires, it sits about as low as a regular 2 wheel
drive. Even with the 3.73 diff.; I can get near 30mpg. at cruising speeds
between 45-50mph.

I found a good one for about $1,300. Admittingly, I only drive it 1% of the time,
as my '87 CRX usually bottoms out near 45mpg.

Mine is NOT a rust bucket!!! It is VERY reliable, all I've replaced is the starter.

So I'm trying to share some hope here. I thank God I don't live in the rust (salt country)

I just got tired of hearing the bad rap, painted with a broad brush stroke.
belt that so many of you suffer from!!!

[BurningSkyline]

Alright, so it seems we're about 1:1 on gas vs diesel... I'm curious if the 350 with TBI would be able to get 20mpg, I looked around elsewhere and all they seem to think is that it can't get any higher than around 16mpg... (Then again, I would bet you those guys on other forums have lead feet and non-mpg friendly driving techniques... ) I don't think a complete drivetrain swap would have the best of investment return times, so thats why I'm not too fond of that idea. I'll get some fuel prices soon for comparisons sake.

Edit: unfortunately I am from salt country, but I have seen a few fairly clean trucks on craigslist.

[razor02097]

If I were to buy a truck it would be diesel.... I would love to put a 4BT and 5 speed in my Jeep.

The later 80's early 90's 6.2 is the one you would want. I heard earlier models had a crank issue or block issue I can't remember exact details.

[BurningSkyline]

I did some math with using current fuel prices (Today @ $4.05/gal for diesel and $3.67 for gas)

I figured I'll be traveling roughly 280 miles per month just to commute to school and work and back. All of my calculations are based off of 320 miles of traveling per month.

I found that at 20mpg with diesel I'd be spending $64.8~month, using about 16 gallons of fuel.
(64.8/16=$4.05 and 16gal*20mpg=320mi)

With Gasoline I Figured 15mpg and I figured I'd be spending $78.29~month, using about 21.3 gallons of gas.
(78.29/21.33=$3.67 and 21.33gal*15mpg=319.95mi (The numbers don't add up because of the repeating decimals.)

So I'm only saving $13.49/mo and $161.88 per year, and obviously this number will be changing because of gas prices. Do gas and diesel prices often go up with each other? I'd like to see what happens when gas hits $4 and what diesel gets to.

Right now whatever I decided to buy depends on the price difference between a diesel or gas truck, and personal preference.

[wmjinman]

I understand wanting a certain type of car that's not known for good gas mileage, but then wanting to get the best you can with it.

Are you willing to do "extreme hypermiling"? Maybe not "extreme" by the standards of this site, but to any "layman"?

The reason I ask is because what you describe, including the 2" lift, are very "UN-aero". To get around that, you'll have to go really slow, which means finding roads you won't be interfering with traffic on, etc. I don't see anywhere on here where you describe your route or anything. It makes a difference. For example, if it's 90% freeway where you'll be going 70 mph, you're pretty much screwed (for getting 20 mpg).

But if your "max mpg speed" is 40 mph, and you're willing to drive 40 mph, and take routes that allow that - and do engine-off coasting as much as possible, maybe run an engine block heater, etc, etc, then you might have a chance.

Were you going to get gnarly-looking fat tires along with the 2" lift? See, that would be hurting your effort, too - even if you pumped them way up, I would think.

But anyway, I'd love to see you post some great results. Even if it's only going from 14 or 15 mpg (which is probably about the best that could be expected outta a rig like that) to - I dunno - 18? But 20 - yeah, I'd like to see you succeed, but I have a hunch you'll have your work cut out for you to do that. - good luck!!

[Beau]

Here is what I would do, if I had the same priorities you seem to have.

Ready?

Buy what you want, and then try to get maximum MPG out of it.

I would start w/ a diesel. Why? There are several reasons - including mileage and massive torque when/where you need it.

But, I would not expect it to get great gas mileage; nothing like some of the astounding numbers people on this forum get. Still, set up properly, and old K5 without a suspension lift and without massive tires should do OK, and you'd be smiling while doing it.

[BurningSkyline]

No I wouldn't be using super big tires, just something big enough to not look stupid. Unfortunately the old Detroit diesels didn't have monstrous torque... Only about 250 but that comes on at about 2k rpm I believe. I'm just wondering if there were any mods such as intakes, headers, exhausts, etc. that could boost the power and mpg a little. I drive pretty laid back and coast a lot anyways so that might help mileage a little

I'm not expecting it to be extremely efficient. I just want a cool truck that gets decent mileage despite its size, aero, and weight.

[War_Wagon]

There are lots of mods you can do to the 5.7L TBI motor found in post '87 gas Blazers. If you decide to go gas, at least get one new enough for fuel injection. I think they went to using an overdrive trans in 1985 or so, so there are a few years where you could get a gas powered, carb'd one with an overdrive, but get something newer than that if you can. That era 350s are not powerhouses (my '86 Vette, which was the top of the heap, first year for factory aluminum cylinder heads, etc etc for that time only makes 235 hp or so, where as my mom's '92 5.0L Mustang with nothing but a factory roller cam and some better tech makes the same with 48 less cubic inches lol). Throttle body spacer, high flow cat, and a K&N filter are your friends with a TBI engine. But I would still go with a 6.2L diesel.

[trooper Tdiesel]

id run one of about 6 different engines. all of which would have a manual trans. and final gear swap somthing in the 2.73/3.27 range. with narrow tires say 215/85/16 or the stock? 235/85/16 tires.
id use a old granny trans, yes that's right a non O\D trans, with the super deep 1st and reverse. ((help with off the line with the road gears)).
a aggressive T-case low range to make up for the tall gears when off road.

most likely id run a stock 6.2 diesel, but there are others.....

3.9L 4BT or isuzu 3.9L 4BD1 or 4BD2 these engines all have max rpms of about 2,800 rpms...so the more aggreseve road gears are more needed for them on the open road to help lower RPMs

if i ran it as a gaser id use a GM 4.3L V-6 that's a 350ci V-8 with two pistons chopped off...the 305ci V-8 gas engine has power levels that are about a wash with the 4.3L V-6 so no i wouldn't use it...

other then those id consider a ford 4.9L I-6 300-6 its little bro the 240-6 or the dodge 318 V-8


if i was really going corny.
id do dedicated Propane with high compression to take advantage of the high octane of propane. the GM 4.3L V-6 would be the easiest to get parts to mod for this....