Gear ratios

[Agui-E7TE]

I have a 5.8L EFI with a C6 and 3.55 gears with 35 inch tires. Absolutely no power off the line, horrible mileage(i think I can get it down to 6 mpg in traffic and does no better than 13 mpg on the highway), cruises at 70 mph just fine.

I've been debating wether I should gear it with 4.56 or 4.88. I am planning on rebuilding my engine to a 393 stroker but I'm wondering what you guys would suggest. I don't think I'll go bigger than 35s but I do have a set of 37s I might use for it. Any advise would be greatly appreciated.

Also, I previously had 32s and with the stock gearing and it felt really powerful but now its really sluggish.

[SteveG]

4.56 would put you pretty close to stock gearing. That's the lowest I would go to keep revs down on the freeway. Of course, if it's power you want, 4.88 it is!

[Agui-E7TE]

That's my dilemma, should I go for power or for highway...I should mention that unlike Sammy Hagar, I can drive 55. This decision is one of the hardest for me.

[SteveG]

It's a tough one. Does it have an 8.8?

[Agui-E7TE]

It does but I have thought about swapping in a junkyard 9-inch.

[Polarcub]

With having the C6 I would stick with 4.56 possibly even 4.10s if you are on the street alot. As a point of reference with 4.88's in mine and the E4OD I am turning about 3200 at 65 out of overdrive. Philo already mentioned it earlier but you can do some gear work on the C6 too but without overdrive for your combo I think I would go 4.10 to retain the driveability on the highway. It is always a game of give and take

[SteveG]

I think I would give 4.10 a shot. It might be a happy medium... low enough to get some power back but high enough to keep revs relatively low on the freeway.

[Mojo]

Any suggestions on where to buy R&P's and Truetrac that might be cheaper than Summit?

[Mojo]

I think you will like that set up I really like the 4.88s...on a side note please let us know how you like the generals on the street I am thinking that they will be my next tire[/quote]

Polarcub, I have 35" General Grabber AP's not the new style Red Labels, but I can still let you know!!!

[mesquito_creek]

I just did the maiden voyage from baja back to AZ across the 8 hwy... 4:88 gears, 35 inch BFG ta , stock 5.0L, manual 5 spd.... turning 3000 rpms at 75 mph... seemed like a pretty good set up to me....

[AussieRod]

I have a 5.8L EFI with a C6 and 3.55 gears with 35 inch tires. Absolutely no power off the line, horrible mileage(i think I can get it down to 6 mpg in traffic and does no better than 13 mpg on the highway), cruises at 70 mph just fine.

I've been debating wether I should gear it with 4.56 or 4.88. I am planning on rebuilding my engine to a 393 stroker but I'm wondering what you guys would suggest. I don't think I'll go bigger than 35s but I do have a set of 37s I might use for it. Any advise would be greatly appreciated.

Also, I previously had 32s and with the stock gearing and it felt really powerful but now its really sluggish.

Augi, if you are upgrading to a stroker, I think 4.10 would be a good choice, unless you will spend more time in the desert than on the highway. The stroker will have more torque, so running a taller gear wont hurt it too much. Just my $0.02.

[PaulW]

Data point.
96 e4od/4.56/35s stock engine. 11.5 mpg on the hwy from Vista to SF. Drove with the traffic mid morning on a weekday. Via Tecate. About 250 miles.
PaulW

[Dust]

Data point.
96 e4od/4.56/35s stock engine. 11.5 mpg on the hwy from Vista to SF. Drove with the traffic mid morning on a weekday. Via Tecate. About 250 miles.
PaulW

Interesting. I'm surprised that it is so low... is this typical?

Data Point:
75 F250 429-well tuned basically stock engine/4speed-manual, 4.10's/35's @ 50-60MPH 14-MPG* w/37's 12-MPG**

* Typical over 8-years.
** Over about a year.

[PaulW]

Data point.
96 e4od/4.56/35s stock engine. 11.5 mpg on the hwy from Vista to SF. Drove with the traffic mid morning on a weekday. Via Tecate. About 250 miles.
PaulW

Interesting. I'm surprised that it is so low... is this typical?

Data Point:
75 F250 429-well tuned basically stock engine/4speed-manual, 4.10's/35's @ 50-60MPH 14-MPG* w/37's 12-MPG**

* Typical over 8-years.
** Over about a year.

===========
Dont forget my weight. The stretch plus the pit box. When I weighed it with 2 spares & pit box the numbers were 3020 front and 4040 rear = 7060. Subtract about 100 for one vs 2 spares. same pit box and always a full 5er on the bumper. Weight reduction would help. The 5er will go away once I get confident regarding the aux tank readings, and the main tank is now smaller and the aux is behind the rear seat . So the distribution will be different these days. Probably the scale weigh is still near 7k.
Back in the day with a stock 96 14.3 was typical in the hwy.
Now days in the desert I am lucky to get 5 or 6mpg.
PaulW

[Dust]

ok mine rolls at about 5500 to 6k a grand would change my numbers.

[AussieRod]

seriously? 6k - 7k lbs?? WOW! My F100 with full gas and propane (160ltrs) and a spare rolls 3988 lbs with me in it.

[BajaF250]

The ole BajaF250 is 7,100 wet with driver and gear. Not a light weight.

[Agui-E7TE]

Rod, It does stays on the road longer than it is off road but once I build the stroker for it, it will probably spend more time in the desert. I really need to get started on finding a good 5.8L to tear into and build as my 393 stroker. This way I don't have to take my bronco out of commission. I'm wondering if the fact that its a speed density system will affect my choice of camshaft since from what I've seen, speed density doesn't take too well to performance cams.

[AussieRod]

RJM Injection has a layover harness and the Mass-air harness to convert the factory harness to mass-air. That would be my first part of the conversion, get it all done BEFORE you go stroker. Nothing is harder than trying to convert it to run better AND sorting out a new bigger engine. He is kinda hard to get hold of, but if you were ready to pull the trigger on buying what you need, he will help you no end with the CORRECT parts to do the job. Then camshaft choices will increase dramatically with mass-air and will really wake the stroker up. A 392 stroker kit in a 5.8 is a good choice, just keep in mind the factory block can only handle so much. Look forward to seeing you progress with it.

[ntsqd]

Getting the harness from BC Broncos may be easier as Chuck seems to have some pull with Ryan.