So I have a 1993 bronco came with a wimpy 302 wanted more out of it than the engine could produce I advanced my timing up and it ****ed my engine along with a rear main seal long story short it's dead and I want to get a 351w from a custom engine shop with 400hp with 450 torque I was told that I will snap my axles with that much power is that true on stock axles 3.55 gears I believe are in front and rear tranny is built like a brick **** house so I'm not worried about hurting the tranny with the extra horses but I'm worrying that I might actually snap an axle it's a daily driver and don't want to hurt anything if I need to upgrade axles I need to know what kind and where to get them thanks all for any advice!

 

I wouldn't worry about it with that much power. Yes, that's a lot of power for the stock drivetrain, but depending on how you drive it and what your tires size is will be a big factor.

If you stay at 33" tires or smaller, and don't try to burnout all over the place, you should be fine as long as you don't try to drag race all over the place.

Currently I'm probably around 300-330 RWHP (power to the wheels, not the flywheel which is probably what the crate motor is specd at) and 600ish torque and my stock axles have held up great over the past 8 months of driving.

I have 33" tires as well. I do not try to do burnouts however, but I accelerate quickly every so often.



Basically, that range of power can get you into trouble with your stock drivetrain, but you'll probably be okay not swapping anything out if everything is in good condition now.

 

Bubba is running a 7.3 powerstroke on his stock front and rear end. It has been holding up to that just fine. As long as they are in good shape, you should be fine. A lot of people say to upgrade the front and rear when you go up in power as much as we are talking, and it wouldn't hurt, but, you will be fine for now. I would consider in the future upgrading though.

 

I run 33" tires now u think 400 horses at the flywheel will spin them on dry pavement? I doubt it but I might be underestimating it

 

Serving suggestion:

http://www.earlycuda.org/images/Tech/Ujoint/UjF01.jpg

 

U think I might need that brace Incase the driveshaft comes apart? I doubt after the power goes through the tranny tcase and driveshaft it will be anywhere close to snapping the ujoints

 

U-joints break and shafts twist and break all the time. If you are putting big power to big tires you are at risk of that happening. Is your fuel tank aft of the axle or snuggled up all cozy with the drive shaft?

 

The fuel tank is aft of the rear axle on a Bronco. If (when) the driveshaft and/or the u-joints let go there is little chance of the fuel tank lighting up but it will make a great lever for a pole vault.

400 crankshaft HP is going to stress the rest of the driveline IMHO. If the OP can get traction then all that power is multiplied by the transmission gear ratios. At that power level I would consider better axles, a traction device such as a limited slip or locker, as well as solid beam u-joints.

Big tires, big HP/TQ and a heavy vehicle all lead to broken parts when someone asks "I run 33" tires now u think 400 horses at the flywheel will spin them on dry pavement?". The answer is yes it will and you better hope those big tires spin and not get good grip because something is going to break if you do this too many times.

Don't get me wrong, I'm all for big power but be prepared to upgrade the other parts when you try to get that power to the ground.

 

It won't be an everyday thing just like every once in a while I Wana be able to stomp it and light the tires up not like a smoldering burnout until the back wheels pop and bald eagles fly out my tail pipes just like be first car inline at the red light and hit it and they spin a little bit I'll call the guy up Hes a family friend I'll tell him put 360 at the crank is that too much power? I want a health engine but don't Wana break **** I like the old school original truck with a big engine in it

 

you will be fine, replace what breaks. the trans would be my concern and you have that covered already. you might consider something to control axle wrap though, this would help keep the driveshaft together and control wheel hop.

your next issue will be the efi system. you will need to convert to mass air, not hard to do at all with wrecking yard parts which is nice. you can then run a tweecer or get a custom tune by a shop.

 

I'm actually going carberated getting away from EFI all together and getting a standalone controller to talk to the tranny to make it shift. Only thing slowing me down is money engine is $5800 turn key crate engine. Gotta put some $$$ away then it'll be back on the road

 

that's disappointing to hear. staying efi with this build is so easy and would outperform the carb setup. to each his own, good luck with the build

 

Are the axles in the Bronco the same as the ones in the 8.8 mustang? I've never modded a truck for more power, but I've put over 500 hp to the ground in all of my mustangs and never had any problems with the stock axles and drove them at the track plenty. Bigger vehicle, bigger tires, 4 wheel drive, driving off road, etc, all make that apples to oranges, but just curious if they were the same axles.

 

I believe they are the same, but I'm not 100% sure. I've thought about the comparison as well because I've read things like that before. It is like you say, apples to oranges, but makes me feel a little more confident with my setup and the HP/torque I have. I do think axle wrap would be the more pressing issue in this case.

 

F-150, Bronco, Mustang, even Explorer 8.8s all have 31 spline axles, Rangers have 28 splines except FX4s have 31. Warn did a strength test and the 31 spline 8.8 are almost as strong as a Dana 60!