4.0 HO vs 401 - Fight!

[PlasticBoob]

8.35:1 Compression ratio?!?!? GOOD GAWD!! No wonder it had such low power (compared to it's size). I wonder what a 401 would make with >9.5:1?

Yup! Typical of most of the engines from the early '70s to the '80s. One area where the 4.0 HO shines is up against the legendary, but weak, Ford 300 (4.9L) inline 6 - that beast put out a bunch of torque down low, but only made 150hp.

I think you have to look at the AMC car versions of the 401 for your answer. We used to have a few of those guys around here, and plenty who have built up the 401s with real dyno numbers... would be nice to get a little help from the 401 posse!

[babywag]

and since we?re still in? about 401...
hp was indeed lower for later years.
i believe 195 was rating for my ?77
so yeah, similar to 4.0...sigh

[PlasticBoob]

Ya know, Tony, you could have been the hero and prevented an awful trainwreck if you would have posted that right away.

I believe you, and so yes, for that year they are similar. 195hp is not a typical 401, though.

I have not seen concrete proof of that rating, though, and Google is telling me that in 1978 the 401 went back up to 210hp. It has been my understanding that the 401 was always rated at 215hp in Jeep applications, but I guess not!

Would be nice to see some actual Jeep literature on the subject for all years, just to be sure.

So, at this point we have the best 4.0 out of a Grand Cherokee making 195hp, and the best Jeep 401 making 215hp. I still contend that 20hp is a noticeable difference and thus they are not "similar" in power, especially when you take into account the 4.0's weak torque compare to the locomotive 401.

Heck, back in the day people paid a premium for a 20hp difference, and that's a lot of the reason why you do not see a bunch of 401s around. 20 to 25hp is not insignificant, and if you look at the photo I posted above, that is what separates each engine option once you get to the V8s. People paid good money for that 20 to 25hp.

[ZackN920]

Why not? If a '76 455 Olds can be making less than a 4.0 HO, lol. *sigh* You smogged-out '80s Grand Wagoneer guys...



So there you have it, straight from my owner's manual. If the 145hp 360 of the '80s was the real smogger, I would NOT call any of the mid-seventies V8s any worse than their contemporaries.

Mines a 90'! Totally different

Your owners manual has that info? That's weird. Service manual, I can see, but an owners manual...huh.

You know, it'd be great to find what the real power is for a full stock late 80's 360, and a stock de-smogged 360. Need some dyno information. I can supply the de-smogged stock engine, but it is tuned on the lean side right now.
There is so much varying info on power output of them. I have also seen a few books that showed 175hp for 80-91 360's in all FSJ's. Don't know what to believe. Here's what I know though. It doesn't feel weaker than my Suburban. My suburban has the L05 350 in it, the TBI engine. They put out 210hp 300ft-lb in stock form, which for the most part is how mine is still set up.


edit-Hey Boob, I just noticed you got that number from the 4V engine. I'm just goin on about the 2V. The 4V wasn't even offered in the later years!
...and i disagree about the 4V 74' 360 being comparable to a 4.0. HP MAY be alike, but even a 2v has a good amount more torque.

[babywag]

Far as I can tell the last years the 401 cr dropped to 8.25 just like the castrated 360.
And I?m not raggin on the 401, but it is a smogger in stock trim.
The 80?s 360 is pathetic.
My ?77 Cherokee(401) got spanked by a stock 2bbl sbf 70?s bronco.

99% of folks would never notice 20hp.
I don?t think anybody is saying a 4.0 is better or anything spectacular just that it makes about same hp, makes similar hp as a smogger 401.

[PlasticBoob]

Far as I can tell the last years the 401 cr dropped to 8.25 just like the castrated 360.

Ahhh.

Far as I can tell the last years the 401 cr dropped to 8.25 just like the castrated 360.
And I?m not raggin on the 401, but it is a smogger in stock trim.
The 80?s 360 is pathetic.
My ?77 Cherokee(401) got spanked by a stock 2bbl sbf 70?s bronco.

I agree completely. yes it's a smogger and I know you're not ragging on it - it is what it is. But I swear to you, truthfully, after my rebuild - with stock tires, stock cam, and dual exhaust from a previous owner (2.25 I think?), I beat a Lexus IS300 automatic in a stoplight race up to around 50-60mph.

99% of folks would never notice 20hp.

We'll have to agree to disagree. My friend had this:



220hp, that I borrowed several times and put several hundred miles on.

And then I had this:



245hp.

Guess who noticed an appreciable difference? Not. Similar. At. All. I think more than 1% of folks would notice 20-25hp on these old vehicles - unless we're talking cars with around 350hp and up.

[babywag]

Well from memory mine wasn?t spectacular.
But it had a big ol winch & bumper up front.
It ran well, pulled hard, but was done by 4k.
Just nothing left.
It was bone stock well under 100k, was my dad?s and well maintained etc.,before I got it.

[FSJunkie]

I have a car made in 1977 with a 232 CID I6 with a factory horsepower rating of 86 SAE Net. It has a 190 CFM 1 barrel carbruetor, 8.0:1 compression, EGR, AIR, TCS...just about every emission control you can think of except for a catalyst. Absolutely completely stock under the hood. I drive it at 7000 feet above sea level where whatever power the engine makes at sea level is reduced by 23%. That rated 86 horsepower at sea level would be 62 horsepower at this altitude. I also have an automatic transmission that the internet experts says wastes 25 horsepower. By that wealth of internet knowledge, I should have 37 horsepower at the wheels at 7000 feet. It is a 3300 pound sedan with a 2.73 axle ratio.

Guess what it's 0-60 time and top speed is at 7000 feet and guess what both are at sea level. Go ahead. I've timed it, I know what the numbers are. Lets see how well you think you know my engine based on what you think you know about smog-era engines.

Also, my friend has a 2014 Subaru Outback and I drove it with a stopwatch in my hand. Guess it's 0-60 time at 7000 feet and think about how it compares to my 1977 car I described above. Keep in mind that only one of these cars gets called a "slow emissions-choked piece of junk that cannot get out of its own smoggy way".

Also, my 1972 Wagoneer has a 360 that is totally stock except it has a 2150 carburetor from a 1984 360. Otherwise, stock smog 8.5 compression, stock smog timing.....smoggy smoggy smoggy slow slow slow slow as people tell me. You tell me what my 0-60 time and 1/4 mile time are at 1500 feet above sea level. Go ahead. I ran it at a drag strip, I know the time. I just want to see what people think it is.

This should be fun.

[PlasticBoob]

LOL, preach it, Nigel! Actually, by my calculations the internet says you should have negative horsepower at this point, and need to get out and push.

[FSJunkie]

LOL, preach it, Nigel! Actually, by my calculations the internet says you should have negative horsepower at this point, and need to get out and push.

Yeah I don't even know how it can even move itself. I swear the exhaust just sounds like six little fluffy bunnies rapidly farting in a specific order. The EGR is recycling their farts back into the air they breathe so that makes their farts weaker, and so on... They're just intoxicating themselves at this point. I think their farts would be more productive if I removed the EGR.

Might as well have fun with this, right? Why not. Humor is everything. I have very dry humor.

[babywag]

I hear some PX-41 in the tank should take care of fluffy bunnies syndrome.
Sadly all mine have cats, so never able to try it out.

[SC/397]

bwahahaha, yup... It's been derailed.

I wonder how much an AW4 can take, and last? It seems they are well built(maybe overbuilt) for a 195hp/235ft-lb engine. With their ability to last 400k+ miles with regular maintenance and all.
Wonder if it (new or rebuilt) could last a solid 200K behind a stock 401 without modification?

195hp for a 360 huh? Last I knew a stock smogged 360 was rated at 145. Desmogged and retuned, ...maybe, but I doubt it. Probably more like 170 if retuned after de-smogging.

The AW4 will handle more power than people realize. Plus, there is some companies that rebuild them to handle even more power. I would put a healthy 360 in front of one without even thinking about it. I would look into up grades for a 401 seeing's how it is a "Torque Monster" and all.

http://www.naxja.org/forum/showthread.php?t=1055170

[rang-a-stang]

here are my thoughts
1) Its not fair to compare any engine built in 1978 to any engine built in the late 90's. If 401 production would have continued into the late 90's (like the I6's did) we would have seen power start to go back up. As technology started finding better ways of controlling smog (like TPI, computer controls, 3 way cats, etc) we see power go up. Lets compare to Ferd's 302. In 1977 302 had 129HP. In 2001 (last year of passenger vehicle Windsor) it had 215hp. That's a 60% increase. For 1977 the 258 had 110HP compared to 195 in the 4.0 HO, again, a 56% increase. So we if assume 401 would have seen a similar boost in power, the late 90's 401 would have had ~345HP. If we use the same calculation on the 320lb/ft of torque, the late 90's 401 has 512lb/ft of torque! 345hp and 512lb/ft would be an AWESOME engine!
2) The power potential of a 401 compared to a 256 is not even fair. A factory 401 has a forged bottom end, meaning (machine work aside) a nice set of heads, a good cam, and a power adder (NOS, Supercharger, turbo) and I should be pushing 500hp relatively reliably. Those same mods on a 256 I would think mid 300HP. Since, pretty much none of us would swap in a bone stock motor I think its the power potential that is the better conversation. If I had a 77 256 in my rig, when it was time to come out, it would not go back in with a stock induction, head, intake or cam.
3) the sound that comes out of a pushrod V8. Especially one with a fat lopey cam in it. Nothing matches it. Nothing.
4) I think it could be argued that a 401 does not weigh all that much more than a 256. Especially a 401 with an aluminum intake and heads.

I respect 256's as rock solid/rock reliable motors. If I wanted a motor that would push my 3500 pound 4WD, never die, and climb telephone poles, it hands down wins. But my truck weights over 4500 pounds so starting with a motor that had (when new) 300+lb/ft of torque is nice. There are also fewer things that feel as American as hearing my truck fire up in the morning and that sound alone is worth the bad MPG.

[FSJunkie]

What the heck is this 256 engine you are referring to?

[PlasticBoob]

Hey FSJunkie, funny seeing you here when I was just about to post this - check it out.

I found a 1978 Popular Science article showing how the SUVs from the Big Three completely destroy that poor pathetic smogger 401. Notice how it gets absolutely demolished by a Dodge 440 going 0 to 60?