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nOOB ENGINE PERFORMANCE QUESTIONS

CDA 455 II

CDA 455 II

ANFAQUE2
Joined
May 19, 2020
Member Number
25
Messages
4,053
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No Country For Old Men
Besides weight and dimensional size;
Is there a difference between a 250HP-400ft/lbs 302 motor and a 250HP-400ft/lbs 460 motor?
OR
To put it another way; what would be more desirable:
A 250HP-400ft/lbs 302 motor or a 250HP-400ft/lbs 460 motor?

I'm pondering a (definite) future engine swap or engine rebuild.
Since I want a final drive ratio of 150:1; I don't want/need high HP.
 
mass and stored rotational energy, which all relates to what RPM those identical numbers are reached.

very broadly, the smaller disp. engine will have less internal resistance and higher compression and be more efficient in all things. The larger displacement will run cooler making the same power and be happier with a heavier load over more of it's life.

pretty much always a rebuild is faster, easier and cheaper than an engine swap
 
AgitatedPancake said:
All comes down to the area under the torque curve on a dyno chart. The basic assumption is that while peak torque might be the same, the larger displacement engine has more torque across the whole spectrum
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Also the larger engine will be putting out more torque off idle just due to more mass in the rotating assembly.
 
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5.0 with aluminum heads can get pretty light. It’s hard to beat a factory roller motor for reliability. So if you aren’t worried about limits of horsepower I would stick with the 302.

You could also have the best of both worlds with a 351 based stroker in the 400-430 CI range.
 
As already stated in round about ways, the answer is no. And as AgitatedPancake stated, you have to look at a dyno chart to be able to compare the differences properly.

As for a choice, it would depend on what your end game is ultimately. If you're looking to build power, the 460 would be the way to go. But if your just going with mild performance, then the 302 would be best.

And I'm not saying you can't built power with the 302, but there is no replacement for displacement when building power. Good luck with whatever choose... :beer:
 
Split the difference with a roller 5.8/351. If you’ve got the budget do a mild stroker like 408 with aluminum heads. But a stock roller 5.8 will be a great engine and have lots of potential down the road.
 
CDA 455 II said:
The same reason why I'd want one with a 1.4L inline-4.
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The reason for it in a 4cyl is they don't have the balls to get over obstacles without getting the rpms way up and or slipping the clutch. With a V8, you have actual power way way lower in the rpm range. Most guys are very happy at 80-100:1 with a v8 manual and about 1/2-2/3 of that with an auto.
 
NorCalJalopy said:
Won’t a big block be happier at that level than the small block? It’s not working as hard.
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Big block is just way cooler. Big block exhaust sound cooler, more torque off-idle, 250/400 easily achievable (and can make much more with little work and inexpensive). Actually, the 460 came from factory made about that.

I almost never see a gas engine with torque much higher than hp except for big blocks. 302 most likely will need to make about 350hp to make 400 ft•tq.
 
CDA 455 II said:
Besides weight and dimensional size;
Is there a difference between a 250HP-400ft/lbs 302 motor and a 250HP-400ft/lbs 460 motor?
OR
To put it another way; what would be more desirable:
A 250HP-400ft/lbs 302 motor or a 250HP-400ft/lbs 460 motor?

I'm pondering a (definite) future engine swap or engine rebuild.
Since I want a final drive ratio of 150:1; I don't want/need high HP.
Click to expand...
I assume this is for your Bronco.

While the 460 would perform better you should stick with what you have. Rebuild if necessary. The 302 is a much more numerous and much better supported engine platform than the 460 and tens of millions more were made. You'll be happier cruising the country with an engine that you can buy parts for anywhere with ease than you will with a flatter torque curve.

CDA 455 II said:
The epitome of engine reliability.:smokin:
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It's less than unremarkable as far as 80s 4-bangers go. It's hard not to make a reliable engine when you're making the kind of power per cubic inch shit made back then.
 
400 ft lbs with a n/a 302 is a tall order, and will probably be in the 5-6k rpm peak range to achieve it, if you even can? Low end power will be non-existant and have a 1200 rpm idle speed

400 ft lbs from a 460 will be basically any stock 460 below torque peak, even the worst from the 73-87 era. Horsepower will be closer to 300 or over depending on platform, and peak torque will be closer to 450.

I think a good example would be :

400 ft lb 302 will operate similar to a 125cc two stroke bike

400 ft lbs 460 will be more like a big bore 4 stroke bike.
 
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I guess I would add, to make a more realistic comparison,

I would say 225 hp/300 ft lb 302 would have more similar power curves as a 300hp/450ft lbs big block.

You could say this would be more like a 250cc 4 stroke bike
 
Winchested said:
I'm 160-1 with a 5.3 and manual and fucking love it.

If this was the case ORD wouldn't have designed a doubler to out behind GM v8s...
Click to expand...

Obviously there is always different preferences.

You actually use first gear low low that often? Seems like a great way to snap parts without even knowing you're bound up.:laughing:

Doublers are great because they have options
 
YotaAtieToo said:
Obviously there is always different preferences.

You actually use first gear low low that often? Seems like a great way to snap parts without even knowing you're bound up.:laughing:

Doublers are great because they have options
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Never broken a dang thing. I'm not a YouTube wheeler(90 percent of the retards you see of flex rocks and rollovers) or a rock bouncer, I know my place.
 
It would depend on application for me.
Need an engine that will rev quick from off idle > 302
Need big torque over a long time period > 460

One thing I like about a smaller V8 in a trail rig is the smaller engine rev faster. Down here in the southeast we go from off idle to full throttle and back in a 3 seconds to get the needed wheelspeed.
 
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Wheres all the LS swap folks?

we45756u.jpg
 
Levigarrett76 said:
400 ft lbs with a n/a 302 is a tall order, and will probably be in the 5-6k rpm peak range to achieve it, if you even can? Low end power will be non-existant
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This

The small displacement engine needs to turn faster to move the same amount of air/fuel to make the torque number.

I suggest stroker BB on nitrous.
 
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