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Old 01-30-2000, 02:36 AM
70Chall383 70Chall383 is offline
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I want to build a 383-magnum that is a step above stock but still have a high school kid be able to pay for gas =) and suggestions? Also this may be kind of a stupid question but what do you think would win in a drag, a 1970 Challenger 383-magnum or a 1970 Chevelle SS 396?

Mike
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Old 01-30-2000, 05:22 AM
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Christopher Christopher is offline
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It really all depends on how much money you want to spend!! I'd use a Edelbrock/Carter/Holley 750cfm carb,Edelbrock Performer intake or the factory 383 deal,shoot for 9.5:1 compression ratio,mill the heads to get at 80cc's(probably about .040)use the 272/455 Mopar cam,or if you want a bit more use the 280/480 Mopar cam.Do a nice valve job,and use the Mopar porting templates,Mopar electronic ign setup.I'm guessing you have a automatic trans.If so, I'd use a converter around 2000 stall.Use a 3.55 gear.Exhaust can be factory manifolds,use 2.5" pipe and a good set of mufflers.As for your question about which engine would win,I'd lean toward the 383 anyday!!
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Old 01-30-2000, 06:33 AM
sublime70 sublime70 is offline
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I'd say Chris is on the money. 10 years ago I had the experience of riding along in a friend's '73 Rallye Challenger (auto/3.91 gears) when it walked off and left a fairly hot '70 396 4 speed Chevelle. The 340 was more or less stock, but with a typical rebuild (little more compression) and some type of mild smooth-idle cam. That experience turned me on to Mopars. The Chevy kid almost cried, and sold it to buy a GTO. Some improvement. Don't let the Chevelle guy give you any crap. Your car is ten times more rare and that 383 will outlast that 396 boat anchor by many years.
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Old 02-01-2000, 04:13 AM
383boy 383boy is offline
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Since the horsepower is close to eachother and a challenger is lighter than the chevelle, you have a good chance at tie but giving that the horsepower of the chevelle is more, I feel that the chevelle will win.


383boy
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Old 02-01-2000, 05:02 AM
360duster 360duster is offline
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You had better take a closer look,it might be a 454 since 396`s don`t usually live to be 30 years old.I raced a 66 ss396 once that turned out to be a 454.It didn`t mater though i still beat him with my 360 Duster.He couldn`t get all that power to the pavement.
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Old 02-01-2000, 05:09 AM
sublime70 sublime70 is offline
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If you really want to toast those Chevy's here's what you do, kid. Save your money, dig ditches, steal from old ladies on the sidewalk, whatever you have to do, get yourself about $400 bucks and order a plain-jane, bare-bones plate nitrous kit from Summit or Jegs. Make sure you have a good fuel pump, like 7 psi at at least 100 or so gallons per hour. Put that 383 back together with a mild cam, decent headers, and good ignition. Install that plate on the intake and paint it to match, epoxy it and sand it down smooth if you have to. Get some various and crusty old mopar engine stickers and put them on the solenoids (after they are painted black, or other discreet color). Believe it or not, most Chevy gearheads will either not notice it or will believe it really is emissions equipment if you BS him a little. Tell him it's EGR or part of the PCV system. This goofy low-buck cheating strategy worked for me all through high school. Even though my '84 Stang wouldn't fall out of a tree when off the bottle (14.10's), it reigned holy terror on all but a couple of cars in town, and 8 years later most of those guys honestly still don't have a clue I gassed them. A mechanically sound 383 will handle 125 horses for years if you have enough fuel supply, watch your timing closely, and use it only from about 2600 to around 5800rpm. DON'T GET CARRIED AWAY or you'll be looking at an expensive boat anchor, but Mopar engines really turn on with a little nitrous (Big bores, short strokes, and long rods!). It's only cheating if the other guy knows it's there. Just my two cents worth.
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Old 02-01-2000, 02:54 PM
hemi-1 hemi-1 is offline
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Just because the SS396 was rated at 350 horsepower vs. the 383's 335 doesn't mean that it really made more horsepower. Horsepower ratings in the 50's and 60's are notoriously inaccurate. I'd pick the 383.

396/375's (not available in 1970 I don't think) were pretty quick, but not the 350 horse versions. Lot more than 25 horsepower difference between the two motors. In 72 or 73 my Dad raced a 70 SS396 with his stock 71 Duster 340 with three-speed stick and outran it three times out of three. The SS 396 had headers too.

As for the 454's, a very few of them in 1970 were the 450 horse versions and were pretty stout, but most were the small port 360 horse versions that were only a little quicker than the 396's.

In the early 70's my daily driver was a 65 Barracuda with a low compression 340 that was stock except for heads milled .030, aluminum intake and 780 Holley, with a 4-speed and 3.23 gears. Just cruising around on the streets, I never came across an SS396 that would outrun it; only encountered two that could stay with me, most couldn't come close.

There's always some that are faster, of course, but a typical stock 350 horse SS396 was just a low 15 second car. No big deal.
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Old 02-05-2000, 07:23 AM
70Chall383 70Chall383 is offline
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How does the 383 handle nitrous as far as wear and tear? There is a '69 firebird formula 400 at school that i would like to give a good run =)
Thanks for all the responses
-Mike
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Old 02-05-2000, 01:48 PM
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Christopher Christopher is offline
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You shouldn't need nitrous to kill that tin indian.But if you must,do what sublime 70 has said,and go easy on the timing,you'll probably have to retard it some.The 383 can handle the 'gas,just be sensible about it.And as a side note,try to keep your racing on a track,and make sure you have a seatbelt on.
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Old 02-05-2000, 07:05 PM
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Glen440 Glen440 is offline
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I think a decent rebuild with some compression and the next up cam from stock and 3.55-3.91 gear would make a mid 13 street terror and with a little spray 12's anyone! I put together a stock 77 400 with 8-1 comp with the stock magnum shaft and 3.91 gears. The car weighed 3750 without driver
and it ran 13.9's at 98mph. Imagine what compression would have done. I'm confident that a stock 383 should be able to run 13.5's
through exhaust. As for the Generous motors
garbage the 383 should walk all over it. My
400 killed a 454 Chevelle so bad he gave up by the middle of second then he stayed way back when I slowed for round two.
Kick some Chebbie
Glen440
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Old 02-06-2000, 05:20 AM
sublime70 sublime70 is offline
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A small shot of nitrous in itself is not going to hurt any part of a healthy 383, especially just a 100 or 150 horse shot, which is all you'll ever need to get well into the 12's. Even with cast pistons you should be okay, but if you overrev it or run it lean it will bite you. People who have trouble with nitrous generally fall into one of three categories. They either:

1.Cut corners on the fuel system or ignition timing setup, or

2. Use it at the wrong times (rpm too low or high)and recklessly, or

3. Don't have a realistic mindset of what their engine and application can handle.

It may not be relevant to 383's but I had a 125 horse plate kit on my 84 Stang, cast pistons and all, and beat the living snot out of it all through high school. It also had a good Mallory Comp 140 fuel pump and only 8.5:1 compression, so it was more forgiving than some combos. With over 130K miles the oilpan had never been off. That bondo-bucket proved to me that nitrous can safely be used on a near-stock daily driver to make it brutally effective for racing on weekends. Use your head, but don't let the reputation of nitrous scare you. In any case, if you're worried about ring wear run a good synthetic like Mobil 1 15/50 or a little better yet, Redline 10/40. Also, during the rebuild, use a "soft hone" on the cylinders to clean up the microscopic grooves and folded metal left on the cylinder walls after honing. It will help reduce ring wear and help break-in. Good luck.
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Old 02-07-2000, 04:31 AM
70Chall383 70Chall383 is offline
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Thanks for the great responses! I appreciate it.
-Mike
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