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383 suggestions
#1556467
12/31/13 12:02 AM
12/31/13 12:02 AM
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Joined: Jan 2005
Posts: 116
Eastern Shore of Maryland
nasty68
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Eastern Shore of Maryland
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What i have is a 383, .030 over with trw L2315 pistons. Flat tops with no valve reliefs. The block has never been decked. At this point i want to keep the bottom end but am looking for suggestions on what to do. My main concern is the pistons. I have read where piston to valve clearance can be a issue. Before i took the motor apart it had the mopar 284/484 installed straight up. Should i deck the block to achieve zero deck with these pistons? Will that cause issues with camshaft selection? I am open to other cam choices. I want to make this thing run better than it did. Best it ran with stock 516's was 13.0's and i am looking to go faster. New heads will be coming once i figure out the short block. Any help is appreciated.
68 dart, 383, 727
2013 Jeep JKU Sahara
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Re: 383 suggestions
[Re: BSB67]
#1556469
12/31/13 10:03 AM
12/31/13 10:03 AM
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Joined: Jan 2005
Posts: 116
Eastern Shore of Maryland
nasty68
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Eastern Shore of Maryland
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68 dart was 3340 with me in it and fastest pass was 104. Will be aluminum heads. Either edelbrock rpm's or maybe the indy ez heads. I would like to see this thing get into the low 12's if not high 11's if it is possible.
68 dart, 383, 727
2013 Jeep JKU Sahara
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Re: 383 suggestions
[Re: nasty68]
#1556470
12/31/13 10:13 AM
12/31/13 10:13 AM
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Joined: Jan 2003
Posts: 24,562
Brookeville, Md
Mr.Yuck
Not enough dumb comments...yet
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Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
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I ran 12.40's (w/ a terrible trans) in a 68 Dart. Motor was a .030 over 383 forged TRW's, 509 cam straight up, lightly worked 915's, Torker II intake, 750DP, Hooker super comps, 3200 stall and 4.56's (to much gear) That motor rev'd like a MoFo. If the trans would have shifted better (slipped bad between 2-3) It would have been closer to low 12's. I'd think you'd want a better cam to get into the high 11's
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Re: 383 suggestions
[Re: Mr.Yuck]
#1556471
12/31/13 12:08 PM
12/31/13 12:08 PM
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Joined: Jan 2003
Posts: 27,421
Balt. Md
383man
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,421
Balt. Md
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Ran 12.30's in a 3550 lb 72 Dart with a stock piston shortblock 383 using 452 heads and the .484 cam. Had the RPM intake and a 750 DP with 3.91's. Problem is with the stock pistons you cant use much more cam or you will have valves hitting the pistons. If you dont change pistons you are limited to your cam choice. Ron
Last edited by 383man; 12/31/13 12:10 PM.
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Re: 383 suggestions
[Re: 383man]
#1556472
12/31/13 12:35 PM
12/31/13 12:35 PM
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Joined: Jan 2005
Posts: 116
Eastern Shore of Maryland
nasty68
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The thing is i have no problem going with a different cam but i don't want to end up with a cam i can't use because of clearance issues. Is it worth notching the pistons for a bigger cam?
68 dart, 383, 727
2013 Jeep JKU Sahara
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Re: 383 suggestions
[Re: Mr.Yuck]
#1556474
12/31/13 01:42 PM
12/31/13 01:42 PM
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Joined: Jan 2005
Posts: 116
Eastern Shore of Maryland
nasty68
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10pt cage, ladder bars, 4.10's, 295/50-15 hoosiers and at the moment a old fairbanks convertor with about 2400 stall. The convertor is going to change for sure. I figured that would come after the cam selection. Yes the pistons will have to come out i just want to reuse them. It's just a short block sitting on the stand right now.
68 dart, 383, 727
2013 Jeep JKU Sahara
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Re: 383 suggestions
[Re: nasty68]
#1556476
12/31/13 10:32 PM
12/31/13 10:32 PM
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Joined: Feb 2005
Posts: 4,318
Prospect, PA
BSB67
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master
Joined: Feb 2005
Posts: 4,318
Prospect, PA
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Okay. So if nothing changes in the suspension, and you want to get to a 12.0 with only a hp increase from what you have now, you'll need about an additional 80 to 100 hp. That is something like a 12.0 @ 113 mph. For a car with a decent racing suspension, you should actually be running a 12.6 now with your 104, and a 113 mph should get you to 11.6s or so.
So, if you work on picking up .3 in suspension, you'll only need 50 to 70 additional hp.
Back to your original question. I think Ron gave you about as close to a real world example as you can probably get.
But I do have another question after re-reading you original post. Do you already using the 2315 pistons in the motor? Can you check P/V with what you have now?
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Re: 383 suggestions
[Re: BSB67]
#1556477
01/01/14 01:58 AM
01/01/14 01:58 AM
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Joined: Jan 2005
Posts: 116
Eastern Shore of Maryland
nasty68
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Eastern Shore of Maryland
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Yes the pistons are in the motor right now. That was going to be my next step, throw the old heads back on and check the piston to valve clearance. Hopefully those numbers will help. What's the best way to do this? Get some play dough and put it on the piston and rotate the motor? I assume i have to do something with the hyd lifter to do this? When the car was running 104 mph it was using water, one of the pistons was shiny like brand new and another was half clean. It had been using water for awhile. This was also with the 2400 stall which was giving me a 1.90 sixty foot time. I would hope going to newer aluminum heads would pick up something from the bone stock 516's.
68 dart, 383, 727
2013 Jeep JKU Sahara
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Re: 383 suggestions
[Re: nasty68]
#1556478
01/01/14 05:35 AM
01/01/14 05:35 AM
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Joined: Aug 2003
Posts: 43,269
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,269
Bend,OR USA
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If you where to change the heads, cam and converter I can see you reaching your goals easily, with the right parts   On the heads buy a set of new aluminum heads with smaller combustion chamber heads than you have now,Eddy RPM or Victors, Indy EZ or 440 Source Stealth heads, you can verify the CC on your heads pretty easily your self with a feed store 50 CC syringe(SP?) and a 4.5 x4.5 wide piece of clear plexiglas or clear acrylic plastic  On the cam I have installed and tested many different grinds and types, I like solid roller cams because they fit most motors with no valve to piston clearance issues  On yours I would look at buying a cam with 245 to 260 degrees at .050 ground on a 105 to 108 lobe seperation angle and try installing it between 100 and 103 ATDC on the intake lobes   Buy a really good custom made race eight inch converter from Turbo Action, ATI, Lupo, PTC, Ultimate or one of the other many good converter companies out thier Don't skimp on the purchases on any of these parts   383 need to rev to make the cars go fast, plan on spinning that short stroke rascal up around 8000 RPM on the shifts, maybe a little higher like 8600 RPM IHTHs 
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: 383 suggestions
[Re: nasty68]
#1556479
01/01/14 01:04 PM
01/01/14 01:04 PM
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Joined: Feb 2005
Posts: 4,318
Prospect, PA
BSB67
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master
Joined: Feb 2005
Posts: 4,318
Prospect, PA
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Quote:
Get some play dough and put it on the piston and rotate the motor? I assume i have to do something with the hyd lifter to do this?
Yes, and yes. Do you have adjustable rockers?
Here is my suggestion. Make a plan to achieve your performance goal. I would start by keeping your focus on the compression ratio and cam and then take a stepped approach to see if you need the pistons cut. Here is my suggestion:
1) Keep your motor assembled for now
2) Buy the heads you want now.
3) Measure where the piston is now relative to the deck.
4) Install new head and check the P/V clearance w/o gasket.
At this point, you'll have some piston to valve clearance numbers. But you're not done. You'll need to adjust those numbers for two things:
1) Milling the head to get to 70 to 72 cc combustion chamber, and
2) Cutting the deck to get to 0.040" quench distance.
So if during the measurements, your piston was down in the hole 0.020" you know you'll need to add another 0.020" to your measured clearance value to reach the 0.040" quench distance. But you'll probably need to mill the heads to get to the 70 to 72 cc. You would subtract that number (probably around 0.020" if you start with a 75 cc head) from your measured clearance value.
So, this is what I guess you will find. The intake valve will be closer than the exhaust valve (assuming 104 to 106 cam ICL install) and you will have enough clearance but you'll be close. But, I don't know if you'll make enough power to reach your goal. I don't think you'll make it on horse power increase alone, you'll need to shave a couple of tenths off the 60 ft. time too, IMO.
I think you can get there without cutting the pistons, but everything needs to be right. Or you could simply cut the pistons and be done with it. but, if you do that, you will need to reduce the combustion chamber the same cc that you remove from the pistons for the valve clearance.
Honestly, your motor runs pretty good now and you should understand why. You probably have 9.5+:1 compression ratio, probably decent quench, and the cam will make decent power. So don't be fooled in thinking that by simply bolting on a better flowing aluminum head it will put a bunch of power in it. The devil is in the details.
So here is my recommendation on the motor if you don't want to cut the pistons. Get the Eddy E-Street heads and have someone like Porter do some bowl work and put a good grind on them, and mill for the target CCs. Deck the block as needed based on the thickness of the head gasket you plan to use. I think that will put and honest 50 hp in the motor with the 484 cam. If you have good P/V with the 484, consider something similar in a faster lobe solid.
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Re: 383 suggestions
[Re: nasty68]
#1556480
01/01/14 01:52 PM
01/01/14 01:52 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
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Master
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Posts: 52,972
Romeo MI
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Yes those 383s need to rev to make power BUT with the bottom end you have now... you wont if you want to keep it in one piece... you would rip the rods in half so your stuck with lower rpm(I will guess 6500 max).. as said check the P to V clearance now so you get a base line then move from that.. since you want to keep the heavy pistons I would have them notched to help lighten them up, with a decent cam and heads you can get to your ET... work on the chassis it needs it now and will need it more with more power... invest in good shocks now... get the front end to move 5" freely 
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Re: 383 suggestions
[Re: BSB67]
#1556482
01/01/14 02:16 PM
01/01/14 02:16 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
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Posts: 52,972
Romeo MI
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Quote:
Mr. P. Because of the short stroke, and long rod it is truly amazing how the bottom will hold together on a 383 with heavy pistons. It is way different than a 440. With a good replacement rod bolt, 7200 should not be a problem assuming everything is appropriately clearance and oiled. I suspect that he will need to be in the high 6s to get to where he want to be, maybe higher.
Oh I know about the 383... I use to run one years ago
and I finally ripped the rod in half after 1 1/2 seasons
turning 7100 rpm with lighter pistons than his...
the next 383 was a destroked but I had good rods and
light pistons turning big rpm
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Re: 383 suggestions
[Re: nasty68]
#1556484
01/01/14 05:30 PM
01/01/14 05:30 PM
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Joined: Jan 2003
Posts: 75,082
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,082
U.S.S.A.
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Quote:
What i have is a 383, .030 over with trw L2315 pistons. Flat tops with no valve reliefs. The block has never been decked. At this point i want to keep the bottom end but am looking for suggestions on what to do. My main concern is the pistons. I have read where piston to valve clearance can be a issue. Before i took the motor apart it had the mopar 284/484 installed straight up. Should i deck the block to achieve zero deck with these pistons? Will that cause issues with camshaft selection? I am open to other cam choices. I want to make this thing run better than it did. Best it ran with stock 516's was 13.0's and i am looking to go faster. New heads will be coming once i figure out the short block. Any help is appreciated.
How much do you have to spend on this project ?
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Re: 383 suggestions
[Re: JohnRR]
#1556485
01/02/14 12:09 AM
01/02/14 12:09 AM
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Joined: Jan 2005
Posts: 116
Eastern Shore of Maryland
nasty68
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OP
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Posts: 116
Eastern Shore of Maryland
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I was pretty much planning on buying a set of heads, cam, rockers and a convertor for the tranny. The short block i wanted to at least keep the parts i have now. I do know the block has never been decked, its been bored .030 and is filled to just below the water pump holes. I know the 383 isn't the ideal motor for big power but i would like to have a strong runner. I don't plan on stroking this motor. I have a 400 block sitting in the corner of the shop and i want the 383 to last a few years until i can start on it.
68 dart, 383, 727
2013 Jeep JKU Sahara
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