We have all been scammed!! Or at least I have... That is to say, that I personally only just found out that advertised horsepower and torque numbers are measured at the ENGINE instead of at the WHEELS. To me this is a big disappointment because it throws off everything I thought I knew about comparing one vehicle to another in terms of power. Also, more specifically I have always wanted to build up an engine and truck and get it dyno-ed and see how much I improved the power compared to what that vehicle was supposed to make when it was new and stock. So essentially without pulling my engine and getting just it dyno-ed I would never know how to compare my built engines power with the advertised power of that engine. And even then it wouldn't be a very helpful comparison because those numbers (power numbers at the ENGINE) don't really mean anything in the real world.

*takes deep breath after long winded rant*

Maybe this belongs more on the performance forums but whatever...

Anyway, I guess I am just ranting and/or wondering if anyone knows the original/stock power ratings at the WHEELS of a 79 Bronco (the vehicle in question) with the 400 and a standard tranny? if not then give me something to daydream about/compare my numbers with by sharing YOUR dyno numbers (at the wheels obviously haha) on your trucks! Hey, would you look at that; I kind of ended this on a fun note!

 

Just hazarding a guess but probably about 125 hp and 240 tq stock at the rear wheels.

400s were pretty sad in stock form. What is your build and numbers?

My build was pretty much identical to one in the engine section; 400 .030 over, aussie heads, comp XE 262, headers etc.

On an engine dyno that build made like 350 hp/450tq.

On my 2wd through a C6 probably about 285 hp and 400 tq at the rear wheels

 

Unfortunately, that's generally the case. Companies like to get the biggest numbers out there, so they like to take little shortcuts like measuring at the engine instead of the wheels, since then they don't have to account for drive train loss, etc.

Your best bet is to simply dyno it before you do any work, and then dyno it after and see what the difference is.

 

Hivolt, I haven't done my engine build or dyno yet. Currently I have one 79 351/400 (not sure which as ive never been into it and i doubt its original so the vin really doesn't tell me) this current engine is in my bronco with C6, NP203, electronic ignition, headers, true dual, and a 4 barrel Holley. Also i suspect it has been at least rebuilt but more likely built up. also i might pick up another 78 351/400 in complete stock form with all the smog stuff still on it and the 4 speed manual and NP205... on that note, Abandoned, yeah i figure what i will do is dyno the stock bronco, and once i have done my build on my current engine i will be swapping it into the stock bronco and dyno again.

At this point though I am just interested to see any numbers on any of your rigs. I was surprised nobody seems to have a thread like this already. Get to bragging guys!

Hivolt: 285 and 400 sound like exactly what I would like to get. I care more about the torque than HP anyhow so those numbers look great.

 

Thunderhorn,

Just to clarify.... The old SAE "gross" HP ratings ended in 1971. In 1972 the began the more accurate "net" rating using normal attached accessories and exhaust. I don't think anyone, even today uses "at the wheel" ratings. Engine HP is important to know just so you know the efficiency of the drivetrain - it all starts by knowing engine output. Not having you engine dynoed, you have to settle for a chassis dyno or an acceleration test. These are more indicative of real world performance since no one drives an engine around!

My eldest son and I are going to be doing a really basic rebuild of a 400 for his truck and we will do a before and after test of some sort. I think we'll be looking to make 300HP at MINIMAL cost.

 

Pretty sure the drive train drains about 25% of the horsepower (on the average).

I have not dyno'd my 520 (yet), but I know a few others that are set up the exact same as mine and are all right about 650hp on 93 octane. I'm actually hoping to add FiTech injection and get a little more out of it.

 

Toyman,

Hopefully details will follow. 650 is impressive!