Axle Gear Ratios? Explorer Street Rod Rebuild Project

I want to rebuild my 5.0 Eddie Bauer into a daily driver/street rod. My main goal is make this as fast as I can from 0-60, but can be driven on the highway without the engine running at 3,000 RPM at 70MPH. So I am looking for people who have experience in changing out the gears in the differentials. As you may know this Explorer already has 3.73 but I am looking to get some real torque from this truck. I don't really believe going as high as 4.88 or 5.14 would be reasonable because this will still be a daily driver for fall and winter. I will not be taking this vehicle offroading, but like I said I am looking for very good torque with reasonable RPM range on the highway. I am looking at a 347 or 363 reverse dome crate motor (supercharger), and semi-auto performance 6 speed or a 4 speed performance auto transmission with O/D. Although a 5 speed would be a lot of fun and give me some more torque I don't want one in this vehicle.

Engine's HP rating (347) 450+
w/out supercharger (363) 500-550+

The torque I want is to be >550 ft. lbs.

Note: I know that you cannot just switch out the engine, transmission, and gears in a vehicle and then it's suddenly a street rod. Don't worry, I am an automotive student and when I graduate I will be starting this project.

Also,
If anyone has any suggestions on the type of engine I should replace my stock one with, I am all ears. I decided to go big or go home with the 363 reserve dome so I could supercharge it. But let's be serious, it's a very expensive switch. If you have had success with a different engine type such as a 347 with dome or flat pistons with higher compression ratios and good power and decent fuel economy I would love to hear your suggestions. This rebuild will not take place for at least 8 months and I have lots of time to perfect what I want to do.


So everyone please give me your thoughts, suggestions, and wisdom on anything you've done with these types of modifications.

 

[Tbars4]

..Welcome here..

..I'm moving your thread over to a sub forum where others may see it and will be able to help you out ..

 

[jd4242]

What size tires?? I would stick with 3.73 or 4.10 max.in my ranger with 5speed I have 3.73 and 26" tires and turn 2700 rpms at 65.also unless you have WIDE good tires,traction is a huge problem with the power you plan to put down..1-3 may turn into being worthless lol

 

[MitchExplorer]

Right now I've got 265/70/16, the truck sits just under two inches higher than stock, but once I change the suspension I would want just under/or the same width of tire, but reduce the amount of rubber by using larger rims, between 17 or 18 inches and not such a tall tire. To help trim some weight at the wheels for smoother riding at higher speeds. Regarding the actual tire tread, very aggressive A/T in the winter and fairly aggressive A/S in the fall. When it comes to tires, or any part of a vehicle that will help me drive more safely. I don't go cheap. It's not worth putting junk tires on your vehicle that you want to push over 500 horsepower and foot pounds torque.

 

[2000StreetRod]

performance exhaust?

In my opinion a desirable option for the 2nd generation Explorer would have been the Windsor 5.8L fuel injected V8. It had lots of low end torque to get the 4,000+ lb Explorer up to speed. Unfortunately, any of the high performance engines that you consider will be limited by the restricted exhaust system. The stock exhaust headers are very restrictive. Even the expensive, and sporadically available, Torque Monster headers are not what I would consider high performance. The problem with any headers (even custom) is the lack of room in the engine bay unless there is a significant body lift. I suggest that you solve the performance exhaust issues before investing in high rev/high hp engine options. Otherwise, you might achieve a high torque but medium power vehicle. Still fun to drive but the "numbers" won't impress anyone.

 

[99SportX]

I wouldn't go any lower than 4.10 personally. Highway rpms start getting up there beyond that with stock tires. I am running 3.73 now but use to run 4.10 with my 5.0. I lost some acceleration with the change but I wanted to drop in something with a trac lok diff.

 

[MitchExplorer]

Yes I will be custom creating/fabricating the headers and exhaust. I will have to customize lots of things. Also the 351 although is a great engine and has good low end torque. I don't see the need to modify the engine compartment to fit the wider 351 instead of simply putting the same size 302 block with a displacement even greater than the 351. You were saying how even headers wont fit easily. I will be changing the suspension to coil overs, this should free up space and reduce weight and will help apply the power to the ground which will be good for acceleration. I don't mean to sound rude when I say this but, I will be pick and choosing most if not all the parts in the driveline. This is going to be a complete rebuild, so I will be able to get the amount of power and torque I want from many other parts. So I do not see the reason for the modification for a 351 instead of the engine I will be choosing for more low end torque when I will be able to get the same results by modifying something I already am modifying. You do make a good point about the engine, but I don't think it's right for this build. I do appreciate the input though. Thank you.

 

[MitchExplorer]

99SportX: I'm not sure if this will reply to your post but I have some questions for you. Have you ever looked into smaller gears? Like 3.55 or any other sized gears than that? And different sized tires and rims? My idea is to have 245-265/40/17-19's. When looking into what type of gears I want I have been using 265/40/18 which is a good sized wide tire so it has good stature but isn't too wide or too tall which allow for the lower truck on a street style suspension. But with the larger rims and less amount of rubber the wheels will weigh significantly less than the tires I have now (265/75/16) with the 3.73 gears so it should help compensate for higher RPM's at highway speeds, right?

 

[99SportX]

Yeah, you will have to run a higher ratio with smaller tires if you want the same feel as stock. You will probably see around a 400rpm increase at 65mph.

 

[2000StreetRod]

revs per mile

A typical 265/75/16 tire rotates 660 revs/mile
A typical 265/40/18 tire rotates 793 revs/mile
Your 3.73:1 axle ratio would have to be changed to a 3.10:1 to have a comparable engine speed with the low profile tires.

 

[2000StreetRod]

94/95 Cobra pulley?

What are your plans to solve the external balance issue? See Stroking an Explorer 5.0L engine?

 

[MitchExplorer]

As of right now I don't plan on building the engine myself. The engine I'm looking at comes balanced. And how did you figure that out?

 

[2000StreetRod]

internally balanced

I did a quick internet search on 363 crate engines. It looks like most are internally balanced and for carburetors. If that's what you're planning then it would greatly simplify the installation. I thought you were planning to retain fuel injection and your PCM to control the engine. That's a lot more complicated because of the crankshaft position trigger wheel normally installed on the harmonic balancer. I assume that you don't live in an area that requires an annual emission inspection. Most emission inspectors will immediately fail a vehicle that came stock with fuel injection that has been converted to carburetors.

 

[MitchExplorer]

I will be keeping the keeping/ugrading the EFI system. And yeah they are primarily used with carbs, probably for offroading in smaller trucks. But I would just need to specify I'll be using fuel injectors when ordering the block. Regarding the crank sensor, I'll look into that and I'll figure out what to do. I still have a long time before this build will happen. And nothings set in stone.

 

[2000StreetRod]

SFI balancer

I found a 363/500 hp fuel injected crate engine for 85 to 95 Mustangs but it has a distributor. I didn't find any 363 fuel injected distributorless engines. SFI makes a balancer for the 302 with bolt on/off weights for 28 in-oz external or internal balance. It's probably the one that comes with 363 internal balance crate engines. You may be able to press the trigger wheel off an Explorer balancer, machine the SFI balancer to fit the trigger wheel and then press the Explorer trigger wheel onto the modified SFI balancer. Then you just need to install a crankshaft position sensor to use your PCM. The Explorer dress (accessory configuration) is much denser than the Mustang. Also, the clearance between the water pump and the radiator is less on the Explorer. You'll need to move your Explorer dress to the 363 block. That's where the smaller crankshaft pulley comes up. The pulley off a 94-95 Cobra is pretty rare if there are any still available. You may have to get an equivalent fabricated.

You'll need a larger MAF sensor and throttle body, higher flow fuel pump and a custom tune. It would be an interesting project and there will be lots of interest if you post updates as you progress.