340+ for the STREET

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replicaracer43 said:
I don't need a chart, horsepower was rated different in 1968 than it was in like 72 up....do some research yourself.
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So the Magnums were never rated gross horsepower. Net through the drivetrain is not even a fair comparison due to the fact that both engines were tested differently and used with different drivetrain in different vehicles. I get it, but there should be some information somewhere to put both engines on a even playing field. I have seen charts using percentages to convert and may be that's as accurate as you can get.
 
A typical "la" (mid 70s era) 318 makes like 180 horsepower by using the same method the magnum uses to make 230 horsepower.
 
toolmanmike said:
How is it figured then?
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One is with all accessories, the other bare, ran before installing in the car. Gross is bare, Net is in the car. Now I dont know how they get Net HP readings that dont go thru the drive train, because it is in the car.
 
Net is supposed to be like it's in the cars.
All accessories, timing and carb settings, exhaust.

Gross is just like how we dyno built engines.
So they may not have all or any accessories.
Breather or even stock exhaust. It's pretty open to anyway they want to dyno.
That's why you can't trust or compare to net go.
 
La 318/360 specs haven't changed much.
Even magnum short block isn't very different then there roller cammed LA engine. So you'd have to assume most of the magnum hp gain is thru heads.

Look at the 380 hp magnum create engine.
They dyno over 400 hp with just cam, headers and 4bbl. Even crazy built engines have a hard time hitting 2 hp per cfm but magnum don't. So at least the magnum seems to have an advantage in stock form.

From what I hear ported is where LA shines.
 
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All,

The difference is in the efficiency of the Magnum over the LA. It's a roller motor with closed chamber heads. Either one can be made into a firebreather, IMO pound for pound the Magnum is superior, especially as delivered.

Marion
 
mario03srt said:
All,

The difference is in the efficiency of the Magnum over the LA. It's a roller motor with closed chamber heads. Either one can be made into a firebreather, IMO pound for pound the Magnum is superior, especially as delivered.

Marion
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The closed chamber isn't as good as the open chamber. A hydraulic roller is worthless any a performance oriented build, unless you use solid rollers on it.

So the magnum is at best, not as good as the LA because the rocker system is garbage.
 
I like the magnum in mild street trim, it has numerous advantages over the "la" engines, but just like yellow rose, I don't like the stud rocker arrangement. For all out race purposes, the "la" could be better, but for general street performance, give me a magnum any day.
 
toolmanmike said:
How is it figured then?
Click to expand...
The 318 2bbl was rated at 230 gross hp up to 1971. In 1972, they started using Net horsepower and the 318 fell to 150. 318 Magnums were rated at 230 hp Net. Net is all the accessories being run. If you pull a stock 318 magnum from a Dodge Dakota, and put a 4bbl on it, it will have more hp than a stock 318 pulled from a 70 Duster with a 4bbl on it. I'm not debating, but the 318 magnum has from the factory:
  • better flowing heads w/bigger valves
  • better compression
  • lighter rotating assembly
  • there are some more details that I won't get into....
 
Build what you want. A 340 with OD will need to be built with torque in mind, and 340s are not really built for big torque. Strokers will get you torque, but cost more to build. Mileage wise if it's built right, and the combo's matched, you can get close to 20mpg in a A body with 3-series gears and an OD trans and a 4" stroke. I know E bodies with another 800lbs+ with no OD and auto that get over 17. Octane need is strictly based on engine component choices and design. Has nothing to do with displacement. So get with a builder that knows what you want and how to get it, and get all you want.
 
It was stalled out so I thought I would make a ignorant statement to change it up.:lol:
 
It's not necessarily hard to build fuel mileage. As long your expectation are in check. Plus there's 2 types of mileage in town and highway. Everyone seems more concerned or talks more about highway.
Highway is fairly easy to obtain just add OD.

Even modern cars similar to our cars can't break 20 mpg in town.



We all know the benefits of larger cubic inch
But it's not a free lunch everything comes with trade offs.

Compare 340 vs 416

Both can make the same power say 450 hp.
Torque both are gonna make about 1.2 lbs-ft which equals out to 408 lbs-ft and 500 lbs-ft.
A 340 with 3.91 gears will equal the torque to the ground of 416 with 3.23 gears. And both engines will pump the same cfm at the same speed. Similar mpg.

So both would have similar performance and mileage but the 416 would be considered more steerable.

Sure you could put the same gears in both but the 340 will gain mpg but lose performance compared to 416.

Obviously this is generalized.
 
I still like a stock stroke 340. Much cheaper to build and will likely eclipse your expectations with both power and mileage.
 
Boedighw said:
I would not recommend the FAST EFI.

I have installed the FiTEch with good luck, but would lean towards the Holley Sniper just for the customer support aspect. The big win of the Fitech is the fuel command center. It is a simple solution for a simple problem that trips up a lot of people.

Last, do you have the 340? The more I read these posts, I recommend the modern Magnum family over paying $3-4000 for an ok 340 that will still need something. I think the common 360 380hp crate engine is about $5000.
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I don`t agree, I have a fast 2.0, and the support from comp. cams f.i. department has been outstanding. It`s running vewy vewy (elmer fudd) good for the amount of time I have on it and seems to be trouble free ! It controls timing , fuel mixture and enritchment . Happy w/ it !
 
Now that the topic is back on track, I'm interested in how the OP is going to daily drive a stroker small block with a manual transmission in the middle of an IA snow storm?
 
I did it in an E body... Also did it with a 440+6/auto in an E body... It's called driving. I prefer sticks in snow and ice, even in fwd cars.

Edit - Also in regard to the mileage - my statements include a mix of city and highway as reported by the owners.
Some examples:
A 3900lbs Ebody with a 496/727/3.23s gets 14 mixed driving as reported by the owner.
My 340/4sp/3.23 Ebody got 18 mixed driving, ran low 13s, got 23+ highway, and passed emissions.
My 440+6/727/3.91 Ebody got 16 mixed, ran low 12s, didn't ever measure highway. Drove it year round and it had snow tires for winter.
A different 3800lbs E body with a 422" small block/727/3.23s, runs 108+ in the 1/4, factory type heads, "non-modern" hydraulic cam, gets 17 mixed, but biased towards highway.
Obviously highway is most economical but if you can't get 15mpg out of a street-type small block build of any size in an A body you need to learn to tune and make sure the rest of the car is "right". Biggest killers - not running a vacuum advance, running with under-inflated tires and worn front ends, and poor timing and carb setup.
 
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BrianT said:
Now that the topic is back on track, I'm interested in how the OP is going to daily drive a stroker small block with a manual transmission in the middle of an IA snow storm?
Click to expand...

Interesting question. I have only driven a couple hot stick shift cars and they were fords but I could not imagine using a performance clutch in the snow or even daily driving. We got stuck in
moper said:
I did it in an E body... Also did it with a 440+6/auto in an E body... It's called driving. I prefer sticks in snow and ice, even in fwd cars.

Edit - Also in regard to the mileage - my statements include a mix of city and highway as reported by the owners.
Some examples:
A 3900lbs Ebody with a 496/727/3.23s gets 14 mixed driving as reported by the owner.
My 340/4sp/3.23 Ebody got 18 mixed driving, ran low 13s, got 23+ highway, and passed emissions.
My 440+6/727/3.91 Ebody got 16 mixed, ran low 12s, didn't ever measure highway. Drove it year round and it had snow tires for winter.
A different 3800lbs E body with a 422" small block/727/3.23s, runs 108+ in the 1/4, factory type heads, "non-modern" hydraulic cam, gets 17 mixed, but biased towards highway.
Obviously highway is most economical but if you can't get 15mpg out of a street-type small block build of any size in an A body you need to learn to tune and make sure the rest of the car is "right". Biggest killers - not running a vacuum advance, running with under-inflated tires and worn front ends, and poor timing and carb setup.
Click to expand...

You prefer driving with slicks in the winter? I am not a tire expert but that does not make since.
 
famous bob said:
I don`t agree, I have a fast 2.0, and the support from comp. cams f.i. department has been outstanding. It`s running vewy vewy (elmer fudd) good for the amount of time I have on it and seems to be trouble free ! It controls timing , fuel mixture and enritchment . Happy w/ it !
Click to expand...
Reason that I mentioned FAST is that they've been in the business the longest, plus I have one of their EFI units on my, one of a kind, fuel injection. It's on my 38 Ford Standard Sedan, which I call my 1961 Hotrod, that is almost finished after a 12 year build. Lots of interruptions during that period. It's a Dodge 325 plus .40, Schneider cam and Sanderson headers. That's the hotrod.
 
BrianT said:
Now that the topic is back on track, I'm interested in how the OP is going to daily drive a stroker small block with a manual transmission in the middle of an IA snow storm?
Click to expand...

Simple: Just like I've done for the past several years with a BMW, put on Blizzaks, make sure the anti-freeze is up to snuff, and drive it. And keep it clean of slush and road salt once a week, just like I use to do when these cars were new. Although back then we got lots more snow than we do anymore. Last year, we had two 4" snows. Des Moines seems to get missed a lot.
 
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