318 capabilities??

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rgreule

rgreule

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ok so i have a 70 duster.. i have a stock 318 that i was gonna put in but i dont want it to be a complete slug.. i was wondering if a stock 318 with a good cam, air gap, good carb and a set of headers would run 12s with a 125-150 shot of nitrous.. or if the 318 could even handle that.. thank you the rear gear is 3.91.. un sure on the tire size..
 
125 shot should be ok on stock bottom end parts, 150 is pushing it. I'm guessing 13.2-13.7 depending on converter, gearing & tires.
 
How about finding a 360,and doing the same mods your going to do to the 318,with a decent converter,and the gear you already have(3.91's) it might touch the twelves..and its MUCH more rewarding running the number not having to spray:-D:-D
 
Hot Rod Magazine did an article years ago using a junkyard Duster with a 318 and kept spraying it until they blew it up. Like Hypermite said...all it was able to take was about 150, after that, it went boom.

I have a very similar set up to yours (71 Demon, 318, .030 over, 8 3/4 with 3.91 and a mini spool) and have been as fast as 8.32 in the 1/8th on motor, in really good air. Most of the conversion charts out put this right around the 12.95 to 13.05 range for the quarter. Hope this helps and good luck!!!
 
rgreule said:
ok so i have a 70 duster.. i have a stock 318 that i was gonna put in but i dont want it to be a complete slug.. i was wondering if a stock 318 with a good cam, air gap, good carb and a set of headers would run 12s with a 125-150 shot of nitrous.. or if the 318 could even handle that.. thank you the rear gear is 3.91.. un sure on the tire size..
Click to expand...

Yes it'll handle that.
Open the ring gaps up, something like .026 top and .032 second. I would use Comp's 265DEH cam and I would highly recommend changing the rockers to a good crane or ductile adj. setup because of the high cyl. pressure associated with NOS and it'll give you adjustability with the cam.
Or you could have them grind you one of their nitrousHP cams...
 
there used to be a bloke in the uk (now moved to aus) who had an ausi 4 door valiant with a 318 & 100 shot of nos which ran 11's i'l get some more info on times, specs & pictures soon
 
rgreule said:
ok so i have a 70 duster.. i have a stock 318 that i was gonna put in but i dont want it to be a complete slug.. i was wondering if a stock 318 with a good cam, air gap, good carb and a set of headers would run 12s with a 125-150 shot of nitrous.. or if the 318 could even handle that.. thank you the rear gear is 3.91.. un sure on the tire size..
Click to expand...

stroked 340 said:
How about finding a 360,and doing the same mods your going to do to the 318,with a decent converter,and the gear you already have(3.91's) it might touch the twelves..and its MUCH more rewarding running the number not having to spray:-D:-D
Click to expand...


Normally I say use what ya got in the car allready, but here stoke 340 makes sense. Selling the 318 and roll the money over into a 360 for a nice jump in cubes (42) and lots more arm with it. That equals torque.

The 318 can do well, but being down on cubes is a tuff thing to overcome and doing it reliabley gets tuffer and tuffer the faster you go. I have seen a dude on the net run 11's with his 318 Duster. I don't remember what he did to do it though. Anyway, the faster you go, the more expensive it gets and if the engine is small, it gets more expensive to do and maintain.

Since the 318 has a short stroke, getting the power level up to where it needs to be for 11's will make the car less streetable (If your going to be there at all that is) and a bit nasty on the other components. Higher stall and gears will be needed adding to the stress of the engine and chassis. Weight is also another consideration.
 
here you go breakdown of the build of the "brisbane taxi" + a few pics

1968 Australian Chrysler Valiant VE VIP
1969ish Australian 318 (About 8:1 CR)
Standard bottom end
Standard rods
Hi Vol oil pump
Standard cast pistons, standard bore
Ductile steel piston rings gapped for nitrous
Standard head gaskets
Standard heads with standard valves with bowl work to unshroud valves
Standard head bolts, main bolts, rod bolts.
MP green stripe valve springs
Standard rocker gear, standard pushrods
Mopar Performance .484 hydraulic cam installed straight up.
Double roller timing chain
Edelbrock Performer dual plane inlet port matched to heads
Holley 600 double pumper carby, choke horn removed, edges radiused.
Holley black top electric fuel pump all run in /8 braided hose
Home made headers open for track use.
NGK race plugs colder than standard, NOT indexed.
MSD 6AL ignition, MSD billet dizzy with bodgy nitrous curve, MSD blaster SS coil, MSD plug leads
Big ally rad with electric fan on thermostat
Standard engine mounts welded solid
150hp nitrous with bottle warmer and purge valve
Twin solid state 6v batteries in custom fabbed trays in boot
904 torqueflite autobox
Higher stall convertor, unsure of stall, probably about 2600-2800.
Full manual reverse pattern valve body
Low ratio first gear set
Race bands
8 ¾ rear axle narrowed with 4.10 gears and SureGrip and screw adjustable pinion snubber
3 ½ x 15 Fenton slots with 165/70 x 15 tyres
10 x 15 ET slots with 28.5” x 10.5” slicks
Strange race disc brakes with 4 pot ally calipers
Standard drums on back
SuperStock torsion bars with 90/10 comp eng shocks
Home made superstock springs with front spring clamps and 50/50 comp eng shocks
Body minitubbed, springs in chassis rails, home brewed chassis connectors
Fibreglass hood and scoop
Boot floor remade to fit fuel cell halfway through floor
Tiny silver metalflake steering wheel (manual steering with borgesen joint)
B & M Ratchet Shifter
Race bucket seats
Autometer recall tach with shift light
Mechanical oil pressure gauge
No heater
No back seat, aluminium plate to boot with lucky voodoo mask.
No sun visors
No external mirrors
Silver flake worry beads on rearview mirror
Kenwood stereo with 6 x 9 JBL speakers on mdf parcel shelf plus tweeters in boot lid for those Drag Strip parties!!

13.42 on the motor, 11.73@113 on the nitrous.



taxi big 02.jpg


taxi engine 1.JPG
 
Contrary to popular belief there's a lot more to making power than only cubic inches. If your short block is in good shape and you install a decent set of heads with an appropriate intake, carb, exhaust and camshaft you should be able to easily reach your goals.

If the engine is worn out you'd be better off finding a replacement. To that end a 5.2 Magnum makes more power than a 340 did and they are plentiful and cheap. If you don't want to deal with en EFI conversion you can use the ignition system from you 318 and buy a carb intake for the magnum. A 5.9 would do even better, but they are a little harder to find.

FWIW, my totally stock 5.2 Magnum when 12.70's in a 4000 pound truck. I used boost instead of spray, but either should produce similar results. Your Duster should be about 700 pounds lighter and put you right in the low 12's if the rest of the car is set up right.
 
fzmax said:
Contrary to popular belief there's a lot more to making power than only cubic inches. If your short block is in good shape and you install a decent set of heads with an appropriate intake, carb, exhaust and camshaft you should be able to easily reach your goals.

If the engine is worn out you'd be better off finding a replacement. To that end a 5.2 Magnum makes more power than a 340 did and they are plentiful and cheap. If you don't want to deal with en EFI conversion you can use the ignition system from you 318 and buy a carb intake for the magnum. A 5.9 would do even better, but they are a little harder to find.

FWIW, my totally stock 5.2 Magnum when 12.70's in a 4000 pound truck. I used boost instead of spray, but either should produce similar results. Your Duster should be about 700 pounds lighter and put you right in the low 12's if the rest of the car is set up right.
Click to expand...

You also gain the benefit of a roller cam and better flowing heads (that crack). I agree, if I had this to do I'd look for a 5.9 or 5.2 as my foundation, preferably 5.9, but I wouldn't look down on a 5.2 if it were a good deal.
 
My car 1965 plymouth valiant full race weight is 3180lbs. engine 1971 318 stock bottom end, comp cam 252h cam 205@.050 252 lift, mopar m1 dual plane hooker headers 600 dbl pumper, trans 904 with mopar peformance 2500 stall with cheetah reverse manual valve body, 323 gear 26x8.5 m/t slicks. On the motor ran 9.40 @ 75 mph with 2.20 60ft. 140 shot of n2o ran 7.55 @88 with 1.60 60ft
 
rgreule said:
ok so i have a 70 duster.. i have a stock 318 that i was gonna put in but i dont want it to be a complete slug.. i was wondering if a stock 318 with a good cam, air gap, good carb and a set of headers would run 12s with a 125-150 shot of nitrous.. or if the 318 could even handle that.. thank you the rear gear is 3.91.. un sure on the tire size..
Click to expand...
I have ran several different 318 combinations from stock as the factory delivered, to a forged piston/forged crank motor. The stock motor in a 1979 Cordoba ran real consistant 15.40's @ 86 mph. The built motor in a 72 dart ran 11.81 @ 114 mph. A stock bottom end with a 236 @ 50 solid cam and 273 heads and rockers, Weind Accelerator manifold (20 yrs old) ran 12.94 @ 105. All were with 4.56 rear gears and 28" tires. The lowly 318 likes rpm and will stay together with 7000 rpm passes.
 
Here was my setup about 15 years ago-74 318 .030 over, other than the pistons and new bearings, stock bottom end. Swirl-port heads, 3-angle valve job, Lunati 292 cam (yeah, I know, I over-cam everything, I just like the sound), Weiand single-plane intake, worked Thermoquad, 904 with a Fairbanks kit, 8 1/4 posi out of a cop car (don't know/remember exactly what gears, something around the high 3s) stuffed into a junker 67 Dart. I lightened the Dart pretty well, stripped pretty much the entire interior except for the dash and one seat. Removed the bumpers and other extraneous stuff, but everything else was all steel. Ran 12.30s-12.40s all day long, drove home, drove to work with it all week. I couldn't afford more than one car on the road back then. I duplicated the same motor for my Volare about 6 years ago. In the heavier car with cruisin' gears it was still good for 13.90s.
 
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