gas mileage 91 chevy 454 manual trans

[lime4x4]

Looking at maybe buying a 91 3/4 ton chevy ext cab 8 foot bed 4wd.454 big block with a 3spd manual with O/D to tow a 7300 boat/trailer.Anyone else using one close to the year? The truck is more then capable of pulling that boat just trying to figure out how hard it's going to be on the wallet...lol
trailerboats.com shows it has a capacity of 9500 lbs with an automatic trans.This truck has the heavy duty manual trans.Does the towing capacity remain the same or does it decrease?

 

[Silvertip]

Re: gas mileage 91 chevy 454 manual trans

Towing capacity is generally specified with an automatic because an automatic will start a heavier load than a stick. The difference with the automatic is that the torque converter provides additional torque multiplication that is not available with a stick. That said, I question whether the tranny in this truck is a three speed (1:1 in third) and overdrive in fourth, or whether its a granny gear four speed (super low first gear and still 1:1 in fourth). Big difference here as that would make it a non-overdrive tranny. As for fuel mileage, that engine will likely burn a quart of oil in 1000 miles for the rest of its life and you will rarely see 10 MPG. But it does pull like a mule. It all boils down to how much "non'towing" vs "towing" you do. If you put a lot of miles on without towing, then there are other more economical rigs but with reduced towing efficiency. If this will be a towing only vehicle, then it would work great for you.

 

[bruceb58]

Re: gas mileage 91 chevy 454 manual trans

The towing capacity decreases for the manual transmission. The clutch is the weak link.

 

[Rob454]

Re: gas mileage 91 chevy 454 manual trans

its probably a granny 1st gear so you most likely will start out in 2nd gear. Maybe 1st depending on how big/heavy a trailer. I had a crew cab dually 4x4 with a 454 it was a 89 and that thing towed easy. Plenty of times i wagged the trailer ( couldnt see past the dually fenders) to see if the trailer was there. or i had a buddy crane his neck to look out the back window.
I towed a 5500 pound traikler and never felt it. the gas mileage is gonna suck. Mine got 8 MPG loaded unloaded towing not towing around town on the freeway etc. Thats all it got. I jsut learned to live with it. I ended up selling it because i didnt need it anymore
Rob

 

[tashasdaddy]

Re: gas mileage 91 chevy 454 manual trans

if i'm not mistaken that era was the standard 3 speed tranny with the 4th being overdrive. it doesn't have the granny gear, and will go thru clutches, especially on a steep ramp. the only saver will the if the 4 wd transfer case has 4 low and 4 high.

 

[lime4x4]

Re: gas mileage 91 chevy 454 manual trans

it will only be used for towing the boat that's it.Mainly to Ocean city Maryland about 230 miles one way and all interstate driving atleast 200 miles of it.And yes the transfer case has 4 low,neutral,2wd and 4 high

 

[Bondo]

Re: gas mileage 91 chevy 454 manual trans

If you "Expect" about 8/ 10 mpg,....... You probably Won't be disappointed.......

 

[klicknative]

Re: gas mileage 91 chevy 454 manual trans

I get about 12 with my '77 C20 454 4spd 3.73 rear end, empty and not towing. Learn how to get it moving without slipping the clutch and you'll be fine. Start out in 1st (low or granny) but don't let the RPM's get to high before you shift to 2nd. If you over-rev in 1st gear it torque loads the drivetrain and makes the 1st to 2nd shift nearly impossible. If you know how to drive a stick you can out pull an auto.

 

[nathan104]

Re: gas mileage 91 chevy 454 manual trans

I have a 1988 Chevy 1 ton (non-dually) 4wd w/ 454. I get about 6 mpg. Its worth it though, the truck will pull anything you can tie onto.

 

[Texasmark]

Re: gas mileage 91 chevy 454 manual trans

Heads up on the tranny. If you are wanting to tow a boat with a manual tranny, launching is a nightmare.

It takes a tricky combination of emergency brake, foot brake, and clutching to get your load into the water and travel reliably stopped and to pull it out when leaving. BTDT

Also, backing into the trailer when you are working alone is much easier with a "P" gear (on automatics) as compared to shifting into N, applying the foot brake, then the E brake, getting out, checking where you are, getting back in, releasing the brake, applying the foot brake, shifting into gear and......................

Otherwise have no objections to a manual besides requiring clutches periodically. On an auto, just keep the bands adjusted (if required) and clean fluid. I usually suck out a quart of tranny fluid (thru the dipstick tube) at every engine oil change and replace it.....with Mobil 1 ATF or ATF+4 depending on which vehicle.

Mark