Goal: Reliable purely street sleeper MGB + Ford 302 crate engine (target 250-300hp) + LSD + Traction Bars + Dayton Wire Wheel (72 spoke). Do it right the first time...
Option-1: Add Quaife LSD to stock diff
+ Add the Quaife . Done
+ Retain stock suspension
(-) Strength?
(-) Long term reliability?
(-) Gearing - how much an issue ? Not a daily driver.
Option-2: Replace stock axle w/narrowed Ford 8.8 Traction-Lok + suspension mod
+ 100% Ford drivetrain w/out any gearing or strength worries
(-) Stock suspension mods ?
Looks like cost may be a wash between the two options as I will hire someone for axle narrowing
Thoughts?
Wire wheels? Really? I don't know anything about putting splined hubs on an 8.8. What's that cost?
Gear ratios are VERY important. IMHO, getting them right is more important than having a limited slip differential. My 8.8 came from the boneyard with 3.27:1 gears, so I didn't pay an extra penny to get the ratio I wanted.
I read somewhere that there are now a couple suppliers of lower-ratio gears for Salisbury axles, but that at least one of them is selling made-in-China junk. You can get any ratio you want for a Ford axle, at an affordable price, and manufactured by a reputable brand-name supplier.
One of these days I'll rip out my 8.8 and install the axle I should have chosen in the first place. I'd strongly prefer an 8" because it's lighter. I'd also strongly prefer disk brakes and coilovers...
I guess I will be the counterpoint. How important can rear gears be? I have been running the stock 3.9 for almost 14 years. :) Once you get to an engine with buckets of torque anything from 3.50 down to something in the high 2s is going to work just fine. 3.20s to 3.50s is probably ideal. Then find a 5th gear you prefer. If I ever change gears it will be to a 3.50 something & my .63 5th gear will be reduced to .73 for less gap between 4th & 5th.
Sort of boils down to whether you are building an Interstate cruiser or a hot rod/muscle car that you are going to punch on occasion.
Also, might want to spend some time playing with a gear ratio/rpm calculator. Make sure that your interstate cruising rpm is still in your cam's happy range. Some cams don't like spending all day below 2000rpm.
I still like the Dana 44 for cars in that power range. Good bit stronger than the 8".
Jim
Dan Masters' <a href="http://www.britishv8.org/Articles/chart.xls">Gear Ratio Calculator</a>
Basil has the good German 3.07 and 3.31 gears for the stock rear. Glenn Towery has the stainless thrust washers to replace the copper and fiber ones for anti clunk. There is a newer clutch type posi available for the stock rear also. Cheaper than Quaiffe. The 8.8 and Dana 44 are about equal and if over 300HP, a good idea. The stock MGB, 7.5 Ford, GM S10/Camaro and Toyota rears are fine for V6 and 215 V8 under 250HP.
Link to MGB posi, still not as cheap as American axle units: http://www.ebay.com/itm/MGB-MGB-GT-MGB-V8-MGC-Late-Tube-Type-Limited-Slip-Differential-LSD-3JDriveline-/121171122787?pt=Motors_Car_Truck_Parts_Accessories&hash=item1c365c9a63&vxp=mtr
Also the 8" takes about a 5% hit in efficiency due to the high helix angle.
Jim
That posi isn't much cheaper than a Quaiffe!
Would that be 5% more than the stock B, or just 5% total parasitic loss?
"Another difference between the two rearends is that the 9-inch locates its pinion gear lower on the ring gear to improve tooth contact. This strengthens the rearend assembly but at the cost of approximately 2 to 3 percent loss of power to drive the gears compared to a 12-bolt."
Read more: http://www.superchevy.com/how-to/0304-9-inch-12-bolt-rearend-comparison/#ixzz3FyeQSmTL
It's on the Internet, must be right. Right?
Jim