1973 360

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Dan the man

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I've goole for this information and have had no luck. What's the horsepower and torque for the 1973 360 high performance?
 
I could be wrong, but I don't believe there was a "high performance" 360 available in 1973, since the 340 was still the high performance small block offering- try looking for '74 360 4 bbl. that took the place as the 340's successor.
 
Professor Fate said:
I could be wrong, but I don't believe there was a "high performance" 360 available in 1973, since the 340 was still the high performance small block offering- try looking for '74 360 4 bbl. that took the place as the 340's successor.
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My bad I meant the 1974 360
 
Actually not to bad considering all of the imposed emissions on it and reduced compression ratio.

A lot of people trans it but it’s nothing that an ether a piston replacement can’t fix (super hard back in the day) or a head milling can’t fix. Even though that would require a big cut on the head.

I used to get trashed for using the 360. I just told everyone that I fixed the issue. KB-107’s.
 
rumblefish360 said:
Actually not to bad considering all of the imposed emissions on it and reduced compression ratio.

A lot of people trans it but it’s nothing that an ether a piston replacement can’t fix (super hard back in the day) or a head milling can’t fix. Even though that would require a big cut on the head.

I used to get trashed for using the 360. I just told everyone that I fixed the issue. KB-107’s.
Click to expand...
yes the low compression made them turds. I can remember when I was a kid nobody wanted them. Then everyone realized the cubic inches made them worthwhile...All part of growing pains.
 
I used to race a 75’ 360 in a Demon years back. Earlier ones had core issues.
Anyhow- flat top pistons and build the cam for the exhaust side. They need more exhaust valve open time. 2.02 intake and 1.60 exhaust valves. Nothing special. Early 80’s I was getting over 400hp and like 439ftlbs of torque. Back then every one thought of them as “truck engines.” Lol!
They love the thermoquads too.
 
What was the fastest accelerating vehicle in 1978? Little Red Express pickup with essentially the same motor as the 74 hi-po 360.

The really dog 360s not only had the low compression ratio, but retarded timing, wimpy cam, lean carbs and then catalytic converters. They had way less than 200 horsepower even with a four barrel carb.

For what it's worth, the 74 Duster 360 motor in my 67 Barracuda just ran 13 flat at 106 with the same low compression stock replacement pistons that have been in the motor since 1991 (.100 below deck at TDC), a 450 lift cam that's one step above stock (also been in the motor since 1991) and 3.55 gears.
 
jeff alder said:
I'm not comparing the figures the industry standard made that change.
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Sure, but the fact is that the Commando 273 had significantly less net hp than the gross rating.

BTW, the concept of net hp has been around at least since 1955. Chevrolet published gross and net ratings for its then new OHV V8. This graph is from a 1955 issue of Hot Rod Magazine. Power Pack 265 on the left, standard 2-barrel 265 on the right.

1715882240054.jpeg
 
The other main thing that held the factory 360 and even 318 back was cylinder heads.
The reason 273 & 340 were the factory revvers, is that they had similar head flow per cid, if 318 came standard with the 1.88 360 head and 360 came with something like an SM or Edlebrock heads they all would have similar breathing potential. But very different hp potential.
 
65 Cuda 340 said:
Sure, but the fact is that the Commando 273 had significantly less net hp than the gross rating.

BTW, the concept of net hp has been around at least since 1955. Chevrolet published gross and net ratings for its then new OHV V8. This graph is from a 1955 issue of Hot Rod Magazine. Power Pack 265 on the left, standard 2-barrel 265 on the right.

View attachment 1716250607
Click to expand...
I would never dispute the fact that there is a difference between gross and net. I see it on my paycheck every 2 weeks.
 
Dan the man said:
I've goole for this information and have had no luck. What's the horsepower and torque for the 1973 360 high performance?
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The 74 360 4bbl was rated nearly Identical to the 73 340. except of course the 360 torque-peaked earlier. Those two engines had all the same parts bolted on to them, making the only significant differences, being their strokes.
Furthermore, the only significant differences of the Net engines and the Gross engines was the compression ratios and ignition timing.
IN other words, swap out the 8/1 slugs for 10s, put the timing back, and Shazzam.
The heads on those 73/74 engines were the same
BTW,
I challenge any streeter, with typical street gears, with one with one of these 1.88valve head cars, to swap out the 1.88 heads for 2.02s, with no other changes, and on the street, find the difference in ETs from zero to 60mph, . Good luck.
 
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After I blew up my 65 Barracuda's original Commando 273 in November of 1972 (at app. 150K), I put in a 340 from a wrecked 72 Charger. Low compression motor (8.5 to one), 240 net hp. Previous owner had a 3310 Holley on the original Thermoquad intake manifold. That mis-matched setup fell on its face above 4000 rpm. I swapped that intake for an Edelbrock aluminum intake. Now, otherwise totally stock; this low compression 340 was light years ahead of my Commando 273 performance wise. I'm talking about two full seconds quicker in the quarter.

The 74 360 used the same heads as the later 340s. 1.88 intakes, 1.60 exhaust. They breathed well for their day. They might not have been quite as stout as the early high-compression 340s, but they weren't turds, either.
 
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65 Cuda 340 said:
What was the fastest accelerating vehicle in 1978? Little Red Express pickup with essentially the same motor as the 74 hi-po 360.

The really dog 360s not only had the low compression ratio, but retarded timing, wimpy cam, lean carbs and then catalytic converters. They had way less than 200 horsepower even with a four barrel carb.
Click to expand...
That was the later years no doubt. The 340 cam was also used in HP 360’s. Not all 360-4 engines got the 340 cam. (Cali- standards for emissions were also higher thereby reducing HP further.)
65 Cuda 340 said:
For what it's worth, the 74 Duster 360 motor in my 67 Barracuda just ran 13 flat at 106 with the same low compression stock replacement pistons that have been in the motor since 1991 (.100 below deck at TDC), a 450 lift cam that's one step above stock (also been in the motor since 1991) and 3.55 gears.
Click to expand...
Nice!
AJ/FormS said:
The 74 360 4bbl was rated nearly Identical to the 73 340. except of course the 360 torque-peaked earlier. Those two engines had all the same parts bolted on to them, making the only significant differences, being their strokes.
Furthermore, the only significant differences of the Net engines and the Gross engines was the compression ratios and ignition timing.
IN other words, swap out the 8/1 slugs for 10s, put the timing back, and Shazzam.
Click to expand...
You bet! Read on below.
AJ/FormS said:
The heads on those 73/74 engines were the same
BTW,
I challenge any streeter, with typical street gears, with one with one of these 1.88valve head cars, to swap out the 1.88 heads for 2.02s, with no other changes, and on the street, find the difference in ETs from zero to 60mph, . Good luck.
Click to expand...
I never tried the difference comparison. But this is essentially what I’ve being my 20’s. I took that low compression (‘79) 360 engine and gave it a set of KB-107’s-.030 at zero deck which fixed the compression issue.

With the 1.88 J heads, I installed the Purple 292/.508 cam, Torker II (later switching to a RPM-AG when that first came out.) & headers w/a Holley 600 left over from a 318 build. I later used a AVS which I loved. All in a ‘73-4spd-4.10 Cúda.

Later uninstalled 2.02’s. Then when Edelbrock introduced there RPM head for the small blocks, I grabbed them. I used a heavily modded LD-340 before I gave t the RPM-AG with a big TQ.

Excellent set up by the way. Whipped a modded ‘86-ish Camaro that very night even before I got to the cruise meet spot.
 
65 Cuda 340 said:
The 74 hi-po 360 had 245 net hp. Don't recall the torque.
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By the way, that was 5 more than the 72-73 340s.

I've always suspected that the 275 horse rating for the early high compression 340s was actually a net hp rating, but of course I could be wrong.
 
65 Cuda 340 said:
What was the fastest accelerating vehicle in 1978? Little Red Express pickup with essentially the same motor as the 74 hi-po 360.

The really dog 360s not only had the low compression ratio, but retarded timing, wimpy cam, lean carbs and then catalytic converters. They had way less than 200 horsepower even with a four barrel carb.

For what it's worth, the 74 Duster 360 motor in my 67 Barracuda just ran 13 flat at 106 with the same low compression stock replacement pistons that have been in the motor since 1991 (.100 below deck at TDC), a 450 lift cam that's one step above stock (also been in the motor since 1991) and 3.55 gears.
Click to expand...
Do you remember the specs for the cam that you used?
 
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