All you have to do is pull a 8.8 out of a 04-08 f150 with the 4.6

 

Dang I had no idea. I thought they were all 9.75's. Kinda odd Ford didn't select this rear for the Lightning.

 

Ah, I understand now. I assume most of you forced induction guys run twin screw? What kind of power/torque increase is average for the 4.6 and 5.4's? Would I be right buy guessing 25-40% more horsepower depending on the build and tuning?

I guess my point is that I would have to know specifics. The bottom line is the 9.75 is stronger. If he already has a 9.75, it doesn't make sense to purchase an 8.8, then spend additional money on it only to make it as strong as the axle he already had. Yes, an 8.8 CAN be as strong if built right, but I don't know where the cost of building would cross with buying a new axle? If all this is for the sole purpose of cutting weight, I can understand that completely and that would void my opinion.

Then again, this is just my .02

 

Yep....

You are about to buy a locker and rear cover... Trade your gears with your rear end + they give some cash to a guy with a 4.6/8.8 combo that wants to run big tires. Weld up your axle tubes and buy some aftermarket 31/33 spline axles and you will have a rear end just as strong as the 9.75 and 70lbs lighter...

 

Well as far as power, most 5.4's will do 230rwhp from the factory, I'm around 450rwhp now, and HOPE to hit little over 500rwhp this week if I get to tune with e-85....

The thing is, he is about to spend quite a bit of money in his 9.75.. This would be the perfect time to swap to an 8.8 and spend slightly more money and still have a lighter rear end.

If someone just wanted to run big tires and go slow the 9.75 is the perfect rear end.

 

Actually I had just made a parts list and was looking for feedback. The cover is out as it is unnecessary. I spoke with Troyer about it while we were discussing a few other things and he pretty much told me to the LS in if wasn't giving me problems. But he told me to scribe a line on the axles when I have it apart and in the future when I do switch it out I can examine the axles for any twist. I would love to weigh 70lbs less but it seems like a lot of cash to drop what would be less than a tenth second.

 

70lbs is great, but my truck would still weigh 6000lbs lol. I would just build up your stock rear end. They are stout stock and its cheaper just to upgrade them.

 

It wouldn't be that much more if you planned on doing the new diff etc...

Custom axles are around $300 or so.. no biggy..

Tenth of a second is still a tenth... Could be a difference for that 12.99 or that 11.99...

 

You are going to spend the same amount of money upgrading them minus axles... so why not go ahead and take the advantage of a lighter rear end?

 

You must be one of them guys that totally strip down there truck before you go to the track.

Just add more power to make up for the 70LBs

Phil

 

Ran a Detroit locker in my 72 Mustang ( 11.06 @ 123 ) with various gears (2.75, 3.73, 4.30 and 5.14), it is definitely harsh for a street car. On dry pavement you can hear it engage and disengage, feel it slightly. In the rain or slippery conditions forget it, you might as well be running a spool.

 

LOL

That's actually something I haven't done yet... I'll do that for my quest to 11's with a factory long block...

Only thing I do is air up my front tires, remove my front sway bar, and put on slicks. I normally have crap behind the seat also(tools etc. that I don't trust to leave out).

I could probably loose 200+lbs pretty easily if I started stripping the weight down.

 

Yeah,
all I do id put the DOT slicks on, air up the fronts and run with about a 1/2 tank of gas.

Some guys strip out the hole interior, take off the spar, tailgate and anything else they can get off.

It's a lot less work to just add more power...lol

I may try that some time just to hit a 10.something.

Phil

 

The 3:73 in my Lightning was sufficent and gave me no trouble with the
495HP it was producing as well as the 3:55 in my Terminator that ran 11:22's on that stock rear end. Both stock rear ends held up to all abuse I gave them. (just saying)If it ain't broke, then it don't need fixed. I learned a long time ago that consistency was far better than lowering my ET a tenth.

 

Those numbers surprise me. I guess the factory 5.4 is restricted enough to reduce power to only 230 rwhp? I mean, I understand that with proper tuning, air intake, exhaust, and a few other items, you could manage an extra 50-60 horses without the need for forced induction.

So let's say you do those things and move from 230 rwhp to 280 rwhp naturally aspirated. That means when you add the charger, you can manage up to 450 rwhp? From an thermodyanmic stand point, that's a crazy efficient gain. That's an extra 170 rwhp on top of the tuning you already did. That's essentially a 61% gain in power. That seems unusually high. I guess I don't fully understand the proportions of power gain.