360 pros & cons vs 318

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If you have 4 3/4" axle shafts they are most likely in a GM axle. Your 72 originally had 4" bolt circle front and rear. Are you sure you don't have 4" in the front and 4 1/2" in the back?
 
Lol, no im positive... I know it started out as 5x4" bolt pattern, but the rear end was out of a 72 charger, and cut down, from what i was told by the seller... On the passenger side of the car and driver side, the axle shafts have multiple bolt pattern. Ford/mopar and chevy 4 3/4" , right now the wheels are on the chevy pattern. I want to change it the mopar 4 1/2" pattern for some wheels i have that are universal in both 5x4" as well as 4 1/2" but the studs are to long, so i cant just tap them out and move them, i have to cut them out and buy new ones. I need the drums as well to change the pattern over. Im pretty sure i need new brake shoes depending on the width of the drum right? Not a gm housing by the way. Its an 8 3/4 with 489 case/sg. The axle shafts look like moser,strange axles etc. Just no brand in the center or numbers to identify them. Im not crazy either...
 
My question on the 390 vs 408.
Now with a 318 being internally balanced and 360 being an external balance. how does that effect a stroker kit?
 
AND... with some 360 blocks cast in a weaker iron, and some 318 blocks having a thinner cast and cylinder walls.
 
Ive gone both ways 318>360 and 360>318 and other than MPG being better on a 318, seat of the pants power didn't seem much different.... (talking stock engines here) though I never understood, why all 360s I have ever been into (Magnums included) have dished pistons and 318s don't.... I can see that one difference between the engines being a disadvantage on a 360.
 
At least with magnums the dished pistons on the 360 is to keep the compression down and use the same heads between the 318 and 360. At least that is my theory.
 
I bought a new Ram 1500 with a 360 magnum back in 1994. Had 230 hp. 318 magnum had 220 hp. Took it to the drag strip during a Mopar meet, ran half a second quicker in the quarter than an otherwise identical Ram with a 318 (as I recall, 17 flat vs. 16.50 or thereabouts). We talked about it; he thought they should have been closer since I only had a ten hp advantage. My response was, yeah, only ten more peak hp, but the extra 42 inches gives me a stronger low and mid range.

The difference in cubes between a 318 and 360 is exactly the same as the difference between a 360 and a 402 stroker. All other things being equal, which is gonna make more power - the big motor or the smaller one??
 
65 Cuda 340 said:
I bought a new Ram 1500 with a 360 magnum back in 1994. Had 230 hp. 318 magnum had 220 hp. Took it to the drag strip during a Mopar meet, ran half a second quicker in the quarter than an otherwise identical Ram with a 318 (as I recall, 17 flat vs. 16.50 or thereabouts). We talked about it; he thought they should have been closer since I only had a ten hp advantage. My response was, yeah, only ten more peak hp, but the extra 42 inches gives me a stronger low and mid range.

The difference in cubes between a 318 and 360 is exactly the same as the difference between a 360 and a 402 stroker. All other things being equal, which is gonna make more power - the big motor or the smaller one??
Click to expand...


It's really not which one will make bigger power it's where it will make it, idle to 5000 rpm is where street cars mainly live so the rpm is fixed the only way to gain NA HP is torque and displacement is the main way to do that. Now if you don't mind high stalls deep gears high revving engines then rpm isn't a limit anymore and you can spin up a 318 or whatever to make the same power.
 
273 said:
It's really not which one will make bigger power it's where it will make it, idle to 5000 rpm is where street cars mainly live so the rpm is fixed the only way to gain NA HP is torque and displacement is the main way to do that. Now if you don't mind high stalls deep gears high revving engines then rpm isn't a limit anymore and you can spin up a 318 or whatever to make the same power.
Click to expand...
Yeah, given the same induction, CR, cam, heads and exhaust, theoretically a 318 and a 402 would make the same peak power; the 318 would just make it at a higher rpm. That's if you can physically turn enough rpm's in the 318 to achieve the same peak airflow as the larger motor does at a much more modest rpm. I think I read somewhere that, in the real world, that's not quite true, as the extra friction of the higher rpm would cost some peak power in the smaller motor. Regardless, the bigger motor will make more hp low and midrange - everywhere below absolute peak, and would be a much more flexible motor, and therefore a better street motor. Which is basically what you're saying, of course. I'm just adding my extra two cents because I'm quarantined at home and have too much time on my hands.
 
I'd go 413 or 440 for cheap. Gonna spend a lot of money on a 360 to get it to run like a big block. Always the same recipe. Best heads, good intake carb and a cam matched for what you want to do. Go for it.
 
66fs said:
I'd go 413 or 440 for cheap. Gonna spend a lot of money on a 360 to get it to run like a big block. Always the same recipe. Best heads, good intake carb and a cam matched for what you want to do. Go for it.
Click to expand...

who knows what the OP did this thread is 8 years old
 
You can get scary with any SBM. It just takes a lil more gear with the smaller ones and the scary doesn't last quite as long.
With a 318 you gotchur first gear scary.
With a 340 you get second gear scary.
With a 360 the scary goes to 80 mph and maybe a bit more, depending on the chassis,lol.

You know how when you torque the lugnuts on your car, you use a breaker bar about 18 inches long and just lean on it a lil to get the footpounds you need? Well imagine your bar was just 70% as long. You would have to jump on it to get the torque into the ballpark.
That's like the difference between a 360 to a 318.
>With a 318 you're always jumping on the throttle to getchit done. Whereas with a 360 yur just rolling into it.
>a 360 is a lil over 12% bigger, so right off the hop your 318 needs 12% more rear gear just to try and hang with the 360
> but the 360 makes more torque, and makes it earlier, so the 318 needs more stall as well.

You can flip these around as well.
Say you had a 318 with a 3200 stall and 3.91s.That could be a peppy combo, but obviously would not be fun on a long commute and would burn thru gas in a hurry. Swapping in a 360 would let you ditch the 3.91s for 3.44s, and ditch the 3200 for a 2400.You would be hard pressed to notice a difference in the zero to 60mph contest, and obviously 3.44s are gonna be more hiway friendly.

Now; as to swapping out the automatic. The 318 needs the Torque Convertor, because of the hydraulic Torque Multiplying feature it brings to the combo. The internal ratio can be as high as 1.8 or more, which basically makes it a two-speed, infinitely variable between about 1.1 and 1.8, power multiplier. The multiplier automatically varies by the torque differential across it and that means it also varies with roadspeed.
The bottom line is, that your 3-speed automatic, actually has one lower gear ratio than you think. The acyual 904 ratios are 2.45-1.45-1.00.. But with the TC included,you can so sorta think of it as 4.41-3.43-1.79-.90-1.00
the black is the first gear spread, the blue is second gear,and green is third gear. The red is at zero slip which can be achieved only while cruising, and only under certain circumstances, or with a loc-up TC. So count 'em up; I get 5 ratios out of 3 gears.

Your 4-speed comes in three verities, the most common is
2.66-1.92-1.40-1.00 compare that to your 904
4.41-3.43-1.79-0.90-1.00
You see what happened there?
But don't despair quite yet.
Your stock LA smoggerteen might make 200ftlbs at 1800stall, so when you floor it,with 3.55s, at zero mph, she might put down 3130 ftlbs into the rear axles, which is enough to break the tires loose. When it does the TC ratio will drop back and your ftlbs might drop to as low as 2260 usually not enough to sustain the spin thru the entire first gear
Now lets look at the 360LA.b 300 ftlbs @2000 so it will put out 2830 ftlbs at zero mph, also enough to break traction. It has no TC to mess it up, and because the tires are already spinning and because it is 12% bigger thab the 318 with vastly more inherent torque, it will continue to spin all the way thru first gear. yes even the stock low-compression job.
But here's the deal ....... you could continue with the A904 and say 2.94s to put down 300ftlbs into that 4.41 starter gear , and put 3850 ftlbs into the rear axles, plenty to break traction. And when the TC rolls back to say 1.4, still have 3030 left at the top of first gear, not even considering the fact that the 360 is gonna make way more than 300 on it's way thru the torque peak.
You see what just happened there?
It's really really hard for a stick car to be as quick on the street as an automatic car, with the same engine and rear gear, and the auto having a decent stall. And you can thank the variable ratio Torque Convertor for that.
There is one problem;
the 360, when warmed up a lil with decent compression, actually makes waaaaay more bottom end torque than your street chassis/street tires, can handle. And if all you can fit is 255s you are in for a scary ride.
But if I remember, that is what you wanted,right? lol.
To tame a hot 360 you will need at least 275s in straight ahead work, and 295s for stability and predictability in the power-turns; remember when sliding sideways, the rear brakes don't work, and the car will pivot around on the front tires....... unless you lock them up, and then you are in an uncontrollable spin . So do yourself a favor and fit the biggest widest front tires on your car, that you can, and learn the fine art of braking....
which with a clutch, is a nightmare; on account of
A) you don't have 3 feet, and
B) your 360 will have way more power than your rear brakes do, so braking and gassing and steering is gonna get exciting, which is what you wanted tho, right? lol.
So bottom line is this;
between a 318 and a 360, it's not even a comparison.
Now; IMO, the 340 has a better balance of street torque than either of these. It has lots more than a 318, but doesn't overwhelm the tires like a 360 does. In srcond gear, with same gearage, I'd rather have the 360 but only because the Hot360 is capable of spinning the tires right thru second gear to 60,70, and even 80 miles per hour .... with 3.55s. You wanted scary right? Try riding that slippery beast to 80 with the rear end wagging around.
Well; yur stock 8/1 360 with iron heads might not hit 80 and still spinning, in Boise Idaho/elevation 2700ft. Noooo, yur gonna need pistons,lol, and some small closed-chambers and 180 psi cylinder pressure. Oh well, it was fun talking about it,lol.
I tell you what tho, if you kept the 904 and upped the stall to 2800 and reused your 3.23s, then, the money you save right there is just about enough for both pistons, a zero-deck, and aluminum closed chamber heads right? You wanted scary? right?
You can get scary with any SBM. It just takes a lil more gear with the smaller ones and the scary doesn't last quite as long. With a 318 you gotchur first gear scary. With a 340 you get second gear scary. With a 360 the scary goes to 80 mph and maybe a bit more, depending on the chassis,lol.



Oh boy, 8yr old thread! I gotta pay more attention!
 
in the cars I have had, stock 318 2 bbl vs stock bigger chamber plus dished piston 360, there hasn't been enough difference to really notice the "advantages" of a 360.... Ive put a couple 318s in place of 360s (because of what was available at a given time, mostly) and in the cars I am talking about there really wasn't enough difference in "get up and go" to matter. Stock, the 318 couldn't even 1 wheel peel and neither could the 360..... then you get into the 80s with the "advertised" 8.something to 1 360s that were actually sub-8 to 1.... most 360s I have had have been gas thirsty pigs. though I have never had the chance to try and improve on one..... which IMHO the best improvements for a 360 would include dumping the dished pistons for flat tops that are at least close to zero deck, for starters.
 
AJ/FormS said:
You can get scary with any SBM. It just takes a lil more gear with the smaller ones and the scary doesn't last quite as long.
With a 318 you gotchur first gear scary.
With a 340 you get second gear scary.
With a 360 the scary goes to 80 mph and maybe a bit more, depending on the chassis,lol.

You know how when you torque the lugnuts on your car, you use a breaker bar about 18 inches long and just lean on it a lil to get the footpounds you need? Well imagine your bar was just 70% as long. You would have to jump on it to get the torque into the ballpark.
That's like the difference between a 360 to a 318.
>With a 318 you're always jumping on the throttle to getchit done. Whereas with a 360 yur just rolling into it.
>a 360 is a lil over 12% bigger, so right off the hop your 318 needs 12% more rear gear just to try and hang with the 360
> but the 360 makes more torque, and makes it earlier, so the 318 needs more stall as well.

You can flip these around as well.
Say you had a 318 with a 3200 stall and 3.91s.That could be a peppy combo, but obviously would not be fun on a long commute and would burn thru gas in a hurry. Swapping in a 360 would let you ditch the 3.91s for 3.44s, and ditch the 3200 for a 2400.You would be hard pressed to notice a difference in the zero to 60mph contest, and obviously 3.44s are gonna be more hiway friendly.

Now; as to swapping out the automatic. The 318 needs the Torque Convertor, because of the hydraulic Torque Multiplying feature it brings to the combo. The internal ratio can be as high as 1.8 or more, which basically makes it a two-speed, infinitely variable between about 1.1 and 1.8, power multiplier. The multiplier automatically varies by the torque differential across it and that means it also varies with roadspeed.
The bottom line is, that your 3-speed automatic, actually has one lower gear ratio than you think. The acyual 904 ratios are 2.45-1.45-1.00.. But with the TC included,you can so sorta think of it as 4.41-3.43-1.79-.90-1.00
the black is the first gear spread, the blue is second gear,and green is third gear. The red is at zero slip which can be achieved only while cruising, and only under certain circumstances, or with a loc-up TC. So count 'em up; I get 5 ratios out of 3 gears.

Your 4-speed comes in three verities, the most common is
2.66-1.92-1.40-1.00 compare that to your 904
4.41-3.43-1.79-0.90-1.00
You see what happened there?
But don't despair quite yet.
Your stock LA smoggerteen might make 200ftlbs at 1800stall, so when you floor it,with 3.55s, at zero mph, she might put down 3130 ftlbs into the rear axles, which is enough to break the tires loose. When it does the TC ratio will drop back and your ftlbs might drop to as low as 2260 usually not enough to sustain the spin thru the entire first gear
Now lets look at the 360LA.b 300 ftlbs @2000 so it will put out 2830 ftlbs at zero mph, also enough to break traction. It has no TC to mess it up, and because the tires are already spinning and because it is 12% bigger thab the 318 with vastly more inherent torque, it will continue to spin all the way thru first gear. yes even the stock low-compression job.
But here's the deal ....... you could continue with the A904 and say 2.94s to put down 300ftlbs into that 4.41 starter gear , and put 3850 ftlbs into the rear axles, plenty to break traction. And when the TC rolls back to say 1.4, still have 3030 left at the top of first gear, not even considering the fact that the 360 is gonna make way more than 300 on it's way thru the torque peak.
You see what just happened there?
It's really really hard for a stick car to be as quick on the street as an automatic car, with the same engine and rear gear, and the auto having a decent stall. And you can thank the variable ratio Torque Convertor for that.
There is one problem;
the 360, when warmed up a lil with decent compression, actually makes waaaaay more bottom end torque than your street chassis/street tires, can handle. And if all you can fit is 255s you are in for a scary ride.
But if I remember, that is what you wanted,right? lol.
To tame a hot 360 you will need at least 275s in straight ahead work, and 295s for stability and predictability in the power-turns; remember when sliding sideways, the rear brakes don't work, and the car will pivot around on the front tires....... unless you lock them up, and then you are in an uncontrollable spin . So do yourself a favor and fit the biggest widest front tires on your car, that you can, and learn the fine art of braking....
which with a clutch, is a nightmare; on account of
A) you don't have 3 feet, and
B) your 360 will have way more power than your rear brakes do, so braking and gassing and steering is gonna get exciting, which is what you wanted tho, right? lol.
So bottom line is this;
between a 318 and a 360, it's not even a comparison.
Now; IMO, the 340 has a better balance of street torque than either of these. It has lots more than a 318, but doesn't overwhelm the tires like a 360 does. In srcond gear, with same gearage, I'd rather have the 360 but only because the Hot360 is capable of spinning the tires right thru second gear to 60,70, and even 80 miles per hour .... with 3.55s. You wanted scary right? Try riding that slippery beast to 80 with the rear end wagging around.
Well; yur stock 8/1 360 with iron heads might not hit 80 and still spinning, in Boise Idaho/elevation 2700ft. Noooo, yur gonna need pistons,lol, and some small closed-chambers and 180 psi cylinder pressure. Oh well, it was fun talking about it,lol.
I tell you what tho, if you kept the 904 and upped the stall to 2800 and reused your 3.23s, then, the money you save right there is just about enough for both pistons, a zero-deck, and aluminum closed chamber heads right? You wanted scary? right?
You can get scary with any SBM. It just takes a lil more gear with the smaller ones and the scary doesn't last quite as long. With a 318 you gotchur first gear scary. With a 340 you get second gear scary. With a 360 the scary goes to 80 mph and maybe a bit more, depending on the chassis,lol.



Oh boy, 8yr old thread! I gotta pay more attention!
Click to expand...

you say 340 have the better balance, couldn't you balance it out with gear choice ?
say you have 360/3.55 and 340/3.55 and say the 340/3.55 is the best balance of traction/torque couldn't you just drop 360 down to 3.23 gears?
and add a 318 to the mix up it's gears to 3.73, to have about the same torque to the ground?
 
273 said:
couldn't you balance it out with gear choice ?
Click to expand...
yes and no
You can equalize the output in the low rpm with gears but then what happens at peak torque and beyond.......
But that's my point exactly.
If cruising comfortably on the hiway is important to you, and overdrive is not in your budget or on the table, you kindof have to limit your gears.
For 65mph with 27"tires; 3.23s= 2600, 2.94s=2370
And for Rapid Transit off the line; that puts the 318 in the outhouse, and the 340 into the doghouse; unless the TC is cranked up, and you can't go too far with that, and even if you do, the smaller rear gears just don't spool up right. And worst of all you have two other bases to hit,namely ; the 3-2 Kickdown at 55mph to safely pass a slowpoke, and the 2-1 kickdown at 32 mph to blowby grampa on Sunday morning.

As to;the 2-1 KD@32mph
you want to be near but above the torque peak, so the tires will lite up, but not so high as to force a 1-2 upshift right away. I like about an 8/1 first gear ratio for this with a 360, so with a 904, that is a minimum rear gear of 3.23 to get about 3150 @ zeroslip/maybe 4100 at 1.3TC-ratio at WOT. Each smaller engine is gonna want the next bigger rear gear, so a 340 might like 3.55s and a 318 might like 3.91s.Of course with 3.91s, your Rs at 32 are 3800@zeroslip/perhaps 4940 at 1.3 slip. And you know the stock 318 is about ready to shift .... so that ain't gonna fly.

As to passing at 55 on the 3-2 downshift;
the 360 with 3.23s is gonna be at 3200@zeroslip, perhaps 3840 @1.2 TC-ratio, about perfect, and by 70 to complete the pass, she might be at 4900 still at 1.2 ratio.
But the poor 318, stuck with 3.91s will hit 55 at ~4650 just about peak power, and by 70 is well past it's prime at 5900, so again, 3.91s are a lousy passing-gear for a stock 318.

This is why,with an automatic, I like the 360 ; it hits all 4 bases with 3.23s.
Put a small spread-bore carb on it so it doesn't blow the tires away in first gear, and you'll never be sorry you chose it.
Pump up the cylinder pressure and it can equal the best smoggerteen for fuel mileage.
Put a lil cam in it and it turns into an animal.
And it does it all with a modest TC and 3.23s.

For those that don't know, for an automatic-equipped car, and in most important to me order, my bases are;
1) Part-Throttle Second gear pull
2) 2-1 kickdown at 32mph
3) cruise rpm
4) 3-2 kickdown at 55 mph
5) take off from zero mph

With a 904, 3.23s are about the best gear to hit them all, but with a stock-type TC, it takes a 360 to pull it off. Forget the smogger318; comparatively speaking, with 3.23s and a 2000/usually less TC, it is dead in the water,
Both stockers; an early hi-compression 340 will compare well with a 360.
But if you pump up the 360, to 340 compression status, it will match the 340 with less cam; and with a 340 cam, will annihilate the 340 on every point.

Of course if you give the 318 some decent compression,usually requiring closed-chamber aluminum heads, a modest solid lifter cam, an A999 with a higher but still modest stall TC; you can make a really nice performer out of it. The A999 will act like a 5 speed; with an automatically adjusting hi/lo ratio in each gear, plus the lock-up feature. And you can do it all with a 3.23 ..
Yes, the 318 will like a 5-speed manual if you insist on a m/t, but then the ratios will need to be re-evaluated.
IMO
A purpose-built 340automatic could be adequate on all 5 points, still with 3.23s ......
but do you want/will you be satisfied with, adequate?
 
at least the threadreopener is using search
he shold be commended
stroker kits can be had internal or external balanced
I've known Tim at SCAT like forever square shooter
there are other good stroker vendors and some not so good
some have their cranks ground in china
some get the cranks rough from china and do finish grind here
pays to do your research
however breaking crank is rare
more of a problem is pushing production by overtightening the crank grinders steady rest- grinding with more force on a now non straight crank
we fixed lots of these early on- I do not know if it is still occouring
 
Wyrmrider said:
at least the threadreopener is using search
he shold be commended
stroker kits can be had internal or external balanced
I've known Tim at SCAT like forever square shooter
there are other good stroker vendors and some not so good
some have their cranks ground in china
some get the cranks rough from china and do finish grind here
pays to do your research
however breaking crank is rare
more of a problem is pushing production by overtightening the crank grinders steady rest- grinding with more force on a now non straight crank
we fixed lots of these early on- I do not know if it is still occouring
Click to expand...
s what stroker rank would you recommend ? price within a few hundred not a factor
 
I have been offered 318’s for free, even delivered to my house and I wouldn’t take them. I was soured on them many years ago (1970’s) when I beat them easily with my 6 cylinder Ford Maverick. And I mean a lot of them and by a lot. 360’s are cheap and 42 cubic inches bigger.
 
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