mods for a 383

[Dr. Righteous]

Hey, guys. This sounds like a cool forum.
I plan to be a regular here so let me start with Life according to me and MoPar.
I lived,breathed and ate MoPar when I was younger. (early 20s) I once owned a '70 GTX, a '71 GTX, '67 Belevedere and a '65 Coronet. All bought to restore all eventually sold for one reason or another. I had the desire but not the money to do them justice. Well it ended up that I got a job offer out of state and had to leave my MoPars behind. And so I did for 6 years. I sold my '89 Mustang GT and bought my '69 Coronet a little over a year ago now. Well, its a plain jane 318 car but that was fine. A rod started knocking so I decided to pull the 318 and ready the '71 383 I bought several months before. NOW, I want POWER from this engine. But still street manners. The short block will remain stock with the exception of a cam and double roller timing chain. What combo of carb, intake, and cam do you guys recommend to make a mid 13 sec car out of this one. It has a 8 3/4 posi with 323 gears in it and a 727 tranny.
Any ideas.
What do you think of the Edelbrock Performer and Performer RPM combos?
I like the RPM but Edelbrock recommends an adjustable valve train with that combo.
What about MP cam and intake?
I have done a lot of reading but I lack the
knowledge of what actually works in the real world.

[PRO]

Hey Doc sounds like youve had some bad cars!I like to see people take the time to research their MOPARS beforehand.I had a 68 sport sattelite w/383 that ran a best of 12.98 on slicks and iI drove it everyday!Heres what was in the motor.66 383 block,bored .030,9.5:1 badger pistons,balanced,turn crank .010,recon rods,hd bolts,windage tray,906 heads(346 or 452s would work too)480 lift/292 dur. cam,this was a "hemi grind" on a wedge bumpstick.Its no longer available but lunati offers one thats almost identical(480 lift/230*@.050).1 7/8" headers,2 1/2"exh,torker intake and 750 vac. secondary holley(.72 pri..78 sec)41* total timing(I know it sounds a little high but it went over .4 sec faster vs.38*),I should mention it was a four speed with 3.55sure grip.I also like the M-1 single plane intake and the .484/284 cam.I dont like the Edelbrock system,its good for mileage but DEFINITELY GIVES UP SOME PONIES in exchange for mileage. This motor redlined at 6400!!!I owned it for 3 yrs. and sold it to a friend who drove it for another two(70K)b4 we decided to fresheen it up and we drove the ever loving crap out of it!!!Good luck....PRO..

[This message has been edited by PRO (edited December 07, 1999).]

[This message has been edited by PRO (edited December 07, 1999).]

[Dr. Righteous]

Thanks PRO. I am on a budget here so I will have to stay out of the short block on these mods. I know I will have to have some head work done. I think the stock compression for this engine was about 8.7:1. I would like around 9.5:1. I can get away with pump gas with that. So you recommend the MP M1 intakes over the Edelbrock. What about the MP cams. The purple shafts (I always wondered aboat that name). Which do you think would work best?

[caveman]

Go with either dual plane intake .The cam to run is the street hemi or the next hyd. cam up above the sreet hemi.(i don't have the book in front of me)stay away from the .509 with your setup unless your going to run a converter.The eidlebrock cam makes good power also,I don't know the specs on it though.Mill the heads to give you around 9.5-1 compression.Use headers also on this beast.
I run a simaler engine in my D 200 pickup.Its rated at 9000 lbs gross wieght ,It weighs in at around 5000 lbs.empty.It takes those pesky little 99 Z 28 camaros and whips them up(the 6 speed ones get me out of the hole but I've got them by a fender at 70 mph.).Not bad for an over weight hauler,just think what it could do in 3600 lbs car.
Also use the MP electronic distributer kit,right out of the box.I would also use adjustable rockers if the budget allows.They really are good for a few HP.I also wouldn't be caught dead without a windage tray.

[This message has been edited by caveman (edited December 08, 1999).]

[This message has been edited by caveman (edited December 08, 1999).]

[Christopher]

I'd use the 280/480 Mopar cam,a 750 cfm carb,and a old Edelbrock Tarantula or Torker.I use this in my Road Runner with 3.23-3.91 gears and it works great.

[Gary]

Dr. Righteous...you wonder about the "purple shaft" name? My guess is it was coined by a former GI. In the old Air Force whenever you were screwed by the system, it was referred to as getting shafted. When you REALLY got screwed, the award was upgraded to the "Purple Shaft", and the top award was the "Purple Shaft with barbed wire cluster". I think the Mopar engineers were thinking of giving the shaft to the competition.

[PRO]

If your going to run 3.23s and a stock torque converter I'd mill the heads .030 which will raise comp. .4,(9.1:1)(you can go .060 but you'll have to mill intake,this raises comp .9)use steel shim head gaskets as Fel pros will drop your comp .2,so stock conv,3.23s and 9.1:1,I'd use MP cam P42866677,.455 lift/272 dur(231*@.050)and Dual plane intake P4529117,I'd use these even if I milled heads .060 and consider a small converter like 2200-2500 stall,Alabama sells an excellent one for around $150,this will really help your holeshot with 3.23s,I think 3.55s or 3.91s would be better.750 vac sec Holley is the carb of my choice,of course I love Holleys to high heaven!!but a 750 Edelbrock is ok too.If you really want 13s go with the holley and stall conv,if you want lower 13s run deeper gears. Have fun ...PRO...

[bg]

Hey guys-
I thought the Purple Shaft cam was called that because the part between each lobe is purple? At least it was in a pic I saw in a Mopar ad-

Brian

[DartGT66]

Bg, true.

[twindad]

[QUOTE]Originally posted by Dr. Righteous:
[B]Thanks PRO. I am on a budget here so I will have to stay out of the short block on these mods. I know I will have to have some head work done. I think the stock compression for this engine was about 8.7:1. I would like around 9.5:1.

Hi Doc,
I've got a 1971 383 engine that I rebuilt last year in a 1973 Charger, and learned alot about the Large tolerances allowed on production engines. My 2 barrel cast crank engine is also rated at 8.7 to 1 compression, but it actually worked out to be about 7.6 to 1 due to these facts:
1. The pistons were Supposed to be .019" below the deck, but were actually .075" down.
2. I used a .038" thick head gasket instead of the thin (.017-.022") steel shim gasket used by the factory.
3. The combustion chambers in stock big block heads tend to be a little larger than spec. My '346's average closer to 88 cc than the 79.5 cc spec I expected.
From my experience, I suggest you check the piston deck height and chamber size. I think you'll have to tear into the block and change pistons or deck the block to get that 9.5 to 1 CR.
My 383 also has a MP 280 duration .471" lift cam in it, Edelbrock Torker 383 intake, and an Edelbrock #1407 Performer 750 carb. It only pulls 8" hg vacuum at 800 rpm idle, so the power brakes don't work. The engine dies when I pull it in gear unless I keep patting the gas pedal. It will move my big Charger decently even with a stock stall converter and 3.23 Suregrip, but that cam needs all the compression it can get, a higher than stock stall converter, and steeper gears. Good luck with your car.

Bill W.

[ChristianCuda]

Dr.D.

You will want to have you heads CC'ed. and measure your quench area this is were most Mopar heads are losing power. I dont remember the specs but maybe smeone else can give them but the quench area is the distance between flat area of the combustion chamber on the head and the piston. You want to make this as small as you can with space for tolerance and proper compression ratio. The other thing is no matter what cam you have if you have stock heads they will need to be ported before any cam will really work well. Mopars especially big blocks were basic pure grunt power machines they have a lot of places for improvement especially in the head area. If you have 906 heads they are good for a stock head but with porting the later smog heads are better flowing especially the 346 heads. The otehr area on the heads to workl on is the exhaust valve needs to be a 1.81 the 1.74 is way to small. The stock intake is fine for most street cars and even some strip cars. Remember more is now always better everything has to be tuned for your individual application and use. If you have any more questions Mopar Muscle did a series on big block heads for three months from march to may of 1999. Check out these articles they are very helpful. The other thing to think about is I tried every torque converter I could from stock to high stall stock and now i am on a 3500 stall the larger the cam the higher the stall and gears dont matter as much because you can adjust gears with tires higher gear ratio smaller tires. Keep the 3.23's for right now make that the last thing you change if necessary. Besides 8 3/4 gears are so easy to change i have gotten it down to around 30 minutes with air tools and a jack adapter I built to hold the carrier.

any ways I guess thats alot more than my two cents.
Christian
68 cuda 383
soon to have a EFI

[68Brent]

Lots of good suggestions here, especially regarding cams and heads. I personally think a real key is a single plane manifold (Torker or Tarantula), you can find them used for a reasonable price, a 750 or 780 vacuum secondary Holly (I prefer the 3310), a good set of headers and a converter with a stall as close to 3000 as you can get. My 66 Coronet ran 13.3's with a stock lower end, stock heads, purple cam, Torker, 3310 Holley, Mallory dual point distributor, 3.55 posi, 2900 stall converter and headers. I did have adjustable push rods (any of those still around?)and a manual shift valve body. On slicks, of course.

[Eldred383]

I am running a 383 in my 65 Satellite, 3750 pounds, 3.55 rear end gears. At sea level it ran 13.84 @ 98 mph with slicks, through the mufflers. I drive this car to work every day, it starts in cold weather and I drive it 45 miles to the local track and 150 miles to Woodburn (Oregon) Dragstrip. Engine is a 1969 short block, never been disasembled. Has a windage tray, Comp Cams 270H (.470 lift, 270/224), stock magnum duel plane intake, Holley 3310 (750 cfm), 1 3/4 inch headers, 2 1/2 inch Flowmasters w/pipes out the back, stock magnum converter. Had Hughes rebuild and due a little LESS than the sage 1 porting on 452 heads. They were a great help, they asked all the right questions. Cylinder presure is what is important. With my cam they said I needed 9.7 static compression to run with premium gas @3700 above sea leval.
Stay with the duel plane manifold and get the cylinder presure right and you will have a great daily driver that will be hard to beat.

[mauve66]

my 1 cent (not as rich as everybody else)
if you are going to stay with the short block spend the money on heads for flow and compression. If you change your mind try to get a mopar experianced shop to do it. My shop put in stock replacement pistons, only ones they knew about, and they are only like 8.2 or so. use a single plane for racing and a dual plane for drivine around and stop light digs. you can get the MP template for porting yourself. its easy. if you are worried get a junk yard set to practice on. measure twice and cut once!! my 383 uses the MP .474 old Hemi grind with 14 inch tires and 3.91. High rpms for local highway driving. like the other guy said leave the gear last, tires are easier to adjust and cruising will be fun. Mine turns the tires easy but gets hurt by the pistons lack of pressure. the MP elect. ignition and orange box is a breeze to install and later you can use the chrome box if you want. windage tray helps but don't be like me and forget the cam when putting it together, the front seal is a bite to close up later on... do the tray and pan last