White Phoenix

[imiceman44]

255/85/16 ( 33.0 tire) / 4l80-e / 70mph

3.73 = 1990 rpm
4.10 = 2187 rpm
4.56 = 2432 rpm
4.88 = 2603 rpm
5.13 = 2736 rpm

if it was me and going to be towing a lot go deep . min 4.56 or deeper to keep the engine in the power band .

255/85/16 (33.0 tire ) / 4l80-e / 80mph

3.73 = 2274 rpm
4.10 = 2499 rpm
4.56 = 2780 rpm
4.88 = 2975 rpm
5.13 = 3127 rpm

at this speed 4.10 looking good to me .

No towing, just traveling and some overland which I can always do in low gear.
I also still have the option of a doubler.
I just don't want to end up like my k5 that was geared great for off road but keeping up with traffic on the highway at 75mph I was at 3200rpm and the engine didn't like it much.

 

[sweetk30]

3.73 = 2132 rpm @ 75
4.10 = 2343 rpm @ 75
4.56 = 2606 rpm @ 75
4.88 = 2789 rpm @ 75
5.13 = 2932 rpm @ 75

 

[bp71k5]

I

F I remember correctly you have the nv4500 right?

Yea. Depends on which gear I’m in obviously.

 

[imiceman44]

3.73 = 2132 rpm @ 75
4.10 = 2343 rpm @ 75
4.56 = 2606 rpm @ 75
4.88 = 2789 rpm @ 75
5.13 = 2932 rpm @ 75

I know those numbers, I am trying to get the feeling that people get with this engine pulling at whatever rpms they are going.
With the numbers game I have a good combo with 38" and 4.10 but I want to see if people ran something like that and how the engine feels.
I hate running the engine faster than it needs to and technically the best mileage is just above the peak torque rpm

 

[imiceman44]

Yea. Depends on which gear I’m in obviously.

How is it in overdrive at 65 or 70mph.
I know that higher speed it will be fine but slower like on busy city highways where you are limited to 65mph

 

[bp71k5]

I know those numbers, I am trying to get the feeling that people get with this engine pulling at whatever rpms they are going.
With the numbers game I have a good combo with 38" and 4.10 but I want to see if people ran something like that and how the engine feels.
I hate running the engine faster than it needs to and technically the best mileage is just above the peak torque rpm

4.10 would feel a little steep with 38” tires I think. I switched from 4.10 to 4.56 with 35” tires, but with a different motor, and the difference was huge in getting rid of how it felt like a dog. I had to really keep the RPMS up artificially high to move the truck around with 4.10. And I could only use overdrive going downhill or driving 75+.

 

[bp71k5]

How is it in overdrive at 65 or 70mph.
I know that higher speed it will be fine but slower like on busy city highways where you are limited to 65mph

65 in overdrive feels tough to stay above ~2000 rpm. It’s right on the border of having to go into 4th gear on any kind of incline or wind. The 454 is better than the 350 in that respect.

 

[imiceman44]

65 in overdrive feels tough to stay above ~2000 rpm. It’s right on the border of having to go into 4th gear on any kind of incline or wind. The 454 is better than the 350 in that respect.

I am counting on the 454 being better in that respect .
The 350 i know feels better at 2200-2500 cruising.
I just haven't driven a 454 much.
I had one but it had a big ass stake bed with a liftgate and a rack and had the sm465.
Didn't drive it much before I shipped it out to @ryoken

 

[bp71k5]

I am counting on the 454 being better in that respect .
The 350 i know feels better at 2200-2500 cruising.
I just haven't driven a 454 much.
I had one but it had a big ass stake bed with a liftgate and a rack and had the sm465.
Didn't drive it much before I shipped it out to @ryoken

Yea, that said, it gets up and goes 80 just fine. If anything I might wish for 4.88 gears with my MT tires. AT tires might cruise a little easier with 4.56 or 4.10 gears and an auto trans if that’s your plan.

 

[blazinzuk]

I know a completely different animal. In my burb with 235/85/16s a turbo 400 and 3.73 70 mph is really where it all feels good. That's almost 3k rpm but my speedo is off a bit so more like between 65 and 70
65 I'm 2700 rpms ish. I get similar milage between there with only very minor improvement dropping to 60 ish.

60 mph is 2500 rpms and I have eeked out almost 11 mpg here. 65 to 70 I'm just above 10 if I push it much above 70 say to 80 ( like 3100 rpms) I drop to a hard 9.

I'd say with a TBI 454 shoot for 2500 rpm cruise. That is where I have pulled my best milage

 

[mrk5]

After switching from the 700r4 to the 4l80e, I've decided I liked the cruise RPM of the 700r4 better than the 4l80e. I have 5.13 gears and 37s. The 4l80 is running about 200RPM higher and it's about 2400RPM at 65.

The truck runs 75 - 80 MPH fine, I just liked the RPMs it was running at those speeds with the 700r4. With the 4l80 I don't like pushing over 70.

 

[imiceman44]

After switching from the 700r4 to the 4l80e, I've decided I liked the cruise RPM of the 700r4 better than the 4l80e. I have 5.13 gears and 37s. The 4l80 is running about 200RPM higher and it's about 2400RPM at 65.

The truck runs 75 - 80 MPH fine, I just liked the RPMs it was running at those speeds with the 700r4. With the 4l80 I don't like pushing over 70.

700r4 has a 0.70 od 4l80e has a 0.74 that's why

 

[imiceman44]

After switching from the 700r4 to the 4l80e, I've decided I liked the cruise RPM of the 700r4 better than the 4l80e. I have 5.13 gears and 37s. The 4l80 is running about 200RPM higher and it's about 2400RPM at 65.

The truck runs 75 - 80 MPH fine, I just liked the RPMs it was running at those speeds with the 700r4. With the 4l80 I don't like pushing over 70.

So I have been checking my rpms on my Jimmy with the 4.3 v6 and I have 2500rpms at 75mph and 2200 at 65 and I like the feeling so with a 454and almost double the torque at lower rpm I feel comfortable with starting with the 4.10 although I still might just get the axles ready and swap out same time I get the lift springs and big tires on.

 

[skunked]

I also think the 2Ksh rpm is a good cruise rpm for the 454 if you can achieve it. I run at 2500 rpm to achieve 55mph and it sucks.

 

[imiceman44]

I also think the 2Ksh rpm is a good cruise rpm for the 454 if you can achieve it. I run at 2500 rpm to achieve 55mph and it sucks.

See that is my concern.
I have been before with my k5, top speed was limited to 60mph governor on the diesel and sm465.
And the k5 is better since it allows the speed but the engine doesn't like it.
I am building this for mainly family trips to anywhere we like so being able to go through a gnarly trail section is a must and I might pull a 5000lbs boat occasionally, although I have the other burb on 33" that will do this mostly, but I need to have a comfortable cruise and best mileage possible, I need anything I can get with a BBC, so that is what will make my decision.
Quiet exhaust is another big thing.

 

[skunked]

See that is my concern.
I have been before with my k5, top speed was limited to 60mph governor on the diesel and sm465.
And the k5 is better since it allows the speed but the engine doesn't like it.
I am building this for mainly family trips to anywhere we like so being able to go through a gnarly trail section is a must and I might pull a 5000lbs boat occasionally, although I have the other burb on 33" that will do this mostly, but I need to have a comfortable cruise and best mileage possible, I need anything I can get with a BBC, so that is what will make my decision.
Quiet exhaust is another big thing.

If I had a 4th gear I would be cruising at 70mph no problem. With the 80E or 700 you'l be fine.

 

[mrk5]

700r4 has a 0.70 od 4l80e has a 0.74 that's why

I know why, I was just trying to give my perspective of how I felt about the differences in RPM created by the gearing change. Given a choice I would probably be strongly tempted to run 4.88 gears rather than the 5.13 with the 4l80e.

 

[imiceman44]

So now I have the tires 37" BFG A/T
And just got the wheels last night, steel black wheels.
Might paint them something lighter, we will see.
I have some 3" front springs and a 4" rear shackle flip, so as soon as I finish moving all the vehicles I have scattered into one storage space and bring this suburban home I will start getting those on.
Pics in a couple of days

 

[imiceman44]

So now I have the tires 37" BFG A/T
And just got the wheels last night, steel black wheels.
Might paint them something lighter, we will see.
I have some 3" front springs and a 4" rear shackle flip, so as soon as I finish moving all the vehicles I have scattered into one storage space and bring this suburban home I will start getting those on.
Pics in a couple of days

2 years and 2 months later, I have some pictures.
And a couple of new options I am thinking of.

So these are the tires.
No lift, one wheel is 3.5" BS and the other is 5" BS.
The tucked in tire clears better on turning so I might run those.

As for engine and transmission:

I am considering the 8.1 in the avalanche.
The truck cost me $2500.
The engine and transmission plus the rear 14bff with disc brakes I think are worth the money.
I will also use the seats, and I could sell the body parts and get some money back.
Am I crazy?
Oh and someone very nice broke my passenger window on the avalanche, and I have too many trucks especially after I got the 1998 suburban 3/4 ton with the L29

Tell me what you think.

To me, in California I have to worry about smog, and the 8.1 has so much potential if I don't have to worry about smog.
I will not be doing this for a couple of months and in the meantime I will get some feedback.

 

[flatland]

That engine(8.1), trans and axle will be awesome in this burb. For that money you will be hard pressed to do any better. You'll love the seats as well.
Can't wait to see updates!