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Re: 383 vs. 440
[Re: CurYellowBird]
#266439
03/28/09 06:42 AM
03/28/09 06:42 AM
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Joined: Jan 2007
Posts: 531
Charlotte, NC
Kowal
mopar
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mopar
Joined: Jan 2007
Posts: 531
Charlotte, NC
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Don't go too far down the depression curve because you don't have '906 heads, for what you are thinking to do other head part numbers will probably work as well since you are going to have them machined. Get the Big Block Mopar book and read up...lots and lots of info in there, including guidelines for cam choices, head mods and rear ends.
Last edited by Kowal; 03/28/09 06:46 AM.
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Re: 383 vs. 440
[Re: CurYellowBird]
#266440
03/28/09 09:27 AM
03/28/09 09:27 AM
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Joined: Jan 2003
Posts: 75,047
U.S.S.A.
JohnRR
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I Win
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Quote:
I have already given it the thought that it would possibly be cheaper to rebuild the factory motor, put in a good cam, and hone or bore out the hi-po manifolds and factory intake to allow for better air flow. Will also port and polish the heads (2.08int., 1.74exh.). Does anyone know if this is the '906' head and if they are good heads?
I want to build this motor up and run real nicely but still have the ability to put a ricer in its place on a rare occasion. Anyone have suggestions for getting a HP 383 to make 400+hp using the "stock" appearing parts such as the intake?
the procedure to hone out the manifolds is going to run your over $1000 , the gains will not be worth the cost .
You need compression in that motor and tight quench , neither are you going to get with stock replacement pistons and the 346 heads ...
Good luck ...
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Re: 383 vs. 440
[Re: JohnRR]
#266441
03/28/09 02:16 PM
03/28/09 02:16 PM
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Joined: Feb 2009
Posts: 583
San Antonio, TX
CurYellowBird
OP
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OP
mopar
Joined: Feb 2009
Posts: 583
San Antonio, TX
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So what do you suggest about the head situation? Should I just find another set of heads or should I just go with larger valves in my 346 heads? Dad's got plenty of books on the mopar motors and what types of engine components will give you in the 1/4.
Project War Bird:
1971 Plymouth Roadrunner
383 4 speed with air conditioning
GY3 Curious yellow
All original
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Re: 383 vs. 440
[Re: CurYellowBird]
#266442
03/28/09 02:38 PM
03/28/09 02:38 PM
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Joined: Feb 2003
Posts: 3,691
MO
cdp
master
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master
Joined: Feb 2003
Posts: 3,691
MO
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I bought my 71 GTX when I was 17 and it took almost 15 years to finish it because of school, work, etc, etc...
If there is nothing wrong with your 383, then do a basic rebuild and enjoy it. Once other "life" things come along, you could easily lose interest. I'm 35, been there, done that.
I HIGHLY recommend you difine what your real goal here is. A nice driver, fun street car that you can take anywhere or a drag car.
If you work with a stock 383 shortblock that gives you true 9-10:1 compression (decking required) and bolt on a good set of heads that are worked (maybe some Stealths), you'll have all the power you need and still have $$ left to work on the rest of the car. You can get it in the 13's pretty easily with the right choice of parts and still maintaining stock appearance and drivebility with, say a 3.23 or 3.55 gear.
Dropping $5K in a motor just to keep up with the big dogs isn't really a good idea if you intend to sell it in the near future.
The 346 heads have hardened seats from the factory, saving you the extra coin on head work. Drop in some quality oversized valves and springs to match your cam will be a good decision. Maybe some home porting with some templates. Or for around 1000 bucks you could be in with some Stealth heads. 440 source says the heads should be taken to a shop for inspection.
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Re: 383 vs. 440
[Re: cdp]
#266443
03/28/09 04:57 PM
03/28/09 04:57 PM
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Joined: Feb 2009
Posts: 583
San Antonio, TX
CurYellowBird
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San Antonio, TX
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All I want is a nice street machine that can get into the low 13's and make it a weekend driver. While I'm in college, I'll come home on the weekends to work on it and my ole man will be working on it during the week. He has the templates to port and polish the heads. I want right around 10:1 compression in the motor and I'll probably just have the factory 3.23 sure grip posi rebuilt just for safety sake. Do the 346 really come with hardened seats from the factory??? I thought they needed hardened seats put in.
Project War Bird:
1971 Plymouth Roadrunner
383 4 speed with air conditioning
GY3 Curious yellow
All original
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Re: 383 vs. 440
[Re: CurYellowBird]
#266444
03/28/09 05:40 PM
03/28/09 05:40 PM
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Joined: Feb 2003
Posts: 3,691
MO
cdp
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master
Joined: Feb 2003
Posts: 3,691
MO
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I "think" some did and some didn't. My 71 already had them and had never been apart before I got it. Maybe someone with more experience can chime in. I was thinking 71 or 72 for sure (both used 346's) had the hardened seats. They are not expensive to have put in if need be or you could go with 452's which, for sure, would have them. Bottom line for my case was that I read way too many magazines with all the latest high end build ups and it actually set me back because I wanted to build what I had read. I should have stayed with my set goals, maintained a realistic budget, etc, and I would have saved money and enjoyed the car FAR earlier than before. Your car is an awesome find and looks as though it is very complete. If the shortblock doesn't have many miles on it, you may just want to swap out a set of fresh heads, restore the carb, then move on to the rest of the drivetrain. You could easily spend 15-25K restoring a car nut by nut and bolt by bolt, but then your scared to drive it, thrash on it, and tearing up your hard earned investment/toy. If you bring a set of heads down to 78cc's or find a good used set of 516's, you can up your compression without touching the shortblock. I think you may be surprised how well a stock 383/4spd will run once its tuned properly and everything else in the drivetrain is up to par. It might not be a 13 sec. car stock, but it doen't take much to get into the 13's with a 383 HP and a few mild performance enhancements. Focus on street use, not racing. As there where you'll be enjoying the car the most. 
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Re: 383 vs. 440
[Re: cdp]
#266445
03/30/09 01:27 PM
03/30/09 01:27 PM
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Joined: Jan 2005
Posts: 1,647
IL
71383beep
top fuel
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top fuel
Joined: Jan 2005
Posts: 1,647
IL
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The 346 heads are open chamber heads. The 383 was actually quite lower in compression then advertised.
The easiest way to get compression is go to a closed chamber head. So with that being said it is worth it to spend some time trying to find 516 or 915 heads. The 915's are the better choice, but are a bit more rare and can be more $$. the 516's work fine though.
If you do not go with closed chamber heads then you're left with boutique pistons or a lot of machine work...or both.
Everybody here is trying to help get your goals but you need to be realistic of the costs and effort needed to get there.
'73 GK6 Challenger Rallye - 340 4-Speed
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Re: 383 vs. 440
[Re: 71383beep]
#266448
03/30/09 02:39 PM
03/30/09 02:39 PM
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Joined: Feb 2009
Posts: 583
San Antonio, TX
CurYellowBird
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I am trying to be very realistic here. I understand the costs that are going to be involved. What you guys have to understand is that my first car and restoration was a chevy. So right now I'm learning the way of mopar from you guys and my dad. He has 516 heads on his 440 so i'm going to talk to him and his buddies and see what they can find for me. Just be patient with me, I want to build a motor the right way and a big block mopar isn't quite the same as a small block chevy. I'm sure that the 3:23 is a good gear but I can probably find a 3:55 no problem. Don't worry about money or effort cause this restoration will be done properly even if i have to sit there with a template and port the heads myself or stay up all night working.
Last edited by Pats71'; 03/30/09 02:41 PM.
Project War Bird:
1971 Plymouth Roadrunner
383 4 speed with air conditioning
GY3 Curious yellow
All original
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Re: 383 vs. 440
[Re: CurYellowBird]
#266449
03/30/09 02:44 PM
03/30/09 02:44 PM
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Joined: Jan 2003
Posts: 75,047
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,047
U.S.S.A.
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Quote:
I am trying to be very realistic here. I understand the costs that are going to be involved. What you guys have to understand is that my first car and restoration was a chevy. So right now I'm learning the way of mopar from you guys and my dad. He has 516 heads on his 440 so i'm going to talk to him and his buddies and see what they can find for me. Just be patient with me, I want to build a motor the right way and a big block mopar isn't quite the same as a small block chevy. I'm sure that the 3:23 is a good gear but I can probably find a 3:55 no problem. Don't worry about money or effort cause this restoration will be done properly even if i have to sit there with a template and port the heads myself or stay up all night working.
I wouldn't put alot of faith in the template porting , especially when you are a NOVICE, gains are MINIMAL at best if you don't screw them up .
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Re: 383 vs. 440
[Re: 71383beep]
#266451
03/30/09 06:07 PM
03/30/09 06:07 PM
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Joined: Feb 2009
Posts: 583
San Antonio, TX
CurYellowBird
OP
mopar
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OP
mopar
Joined: Feb 2009
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San Antonio, TX
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I have a tendency to make myself too open and come under fire lol. This motor won't be my first build. The difference I'm realizing between a small block chevy and a big block mopar is that it's a lot easier to get high compression in a sbc than a big block mopar. Dad explained to me the difference between open and closed chamber heads. Now I understand the kidney bean and toilet bowl descriptions  I'm looking at pistons, heads, decking, etc. My overall goal here is to maintain a factory looking engine that is a sleeper making around 425 hp  . When I go to mopar nationals, its not like they're going to ask me to pull off my valve covers so they can run the numbers on my heads. I want the motor to keep the same intake and hi-po manifolds. The previous owner put on a 750 Carter Competition Carb that will work perfectly after a good rebuild. The one part of this car that makes designing this motor difficult is the combination of the four speed and the factory AC compressor. That AC compressor is huge compared to the R134 compressors I've seen. My hope is to keep the factory AC, which makes it that much harder to choose a cam, heads, etc. that will be able to handle the power steering and AC pump. Luckily the car has manual brakes which kinda helps with the process. I'm open for any design suggestions on this motor. Let me make it clear as well that I am NOT going to put a 525+ lift cam and that I'm not building a racing motor.
Project War Bird:
1971 Plymouth Roadrunner
383 4 speed with air conditioning
GY3 Curious yellow
All original
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Re: 383 vs. 440
[Re: CurYellowBird]
#266452
03/30/09 06:20 PM
03/30/09 06:20 PM
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Joined: Jan 2003
Posts: 75,047
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,047
U.S.S.A.
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Quote:
I'm open for any design suggestions on this motor. Let me make it clear as well that I am NOT going to put a 525+ lift cam and that I'm not building a racing motor.
Well then you are living in a fantasy world with a car as big as you are dealing with , you are going to need compression and a cam with duration to get your HP figure and it may not be condusive to running the A/C ... BUILD A 400 BASED STROKER and it will be easy as pie and LOOK STOCK when you open the hood.
As far as the comparison between the SBC and the 383 to get compression it takes the same thing , BIG DOMES and SMALL combustion combustion chambers , the chevy has the small combustion chamber but you need a dome to get 10.0 in that SMALL BORE with the short stroke.
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Re: 383 vs. 440
[Re: JohnRR]
#266453
03/30/09 06:52 PM
03/30/09 06:52 PM
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Joined: Feb 2009
Posts: 583
San Antonio, TX
CurYellowBird
OP
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OP
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Ok yes all motors require the same thing in order to gain compression numbers. I've just heard that it takes a little more work with a big block mopar. That info is coming from a guy who has built these motors since the mid 70's.
Now it cannot be that hard to get 425 hp out of a 383 big block. Plenty of factory big blocks were claimed to produce that much when they were actually making more. I am not going to build a 400 motor unless I really have to. I want to keep the motor the car was born with. I can understand going with closed chamber heads, 484 lift mp cam, and a good set of 3:55 gears. But I'm not going to rebuild a whole 'nother motor if the factory block is in excellent shape.
Last edited by Pats71'; 03/30/09 07:07 PM.
Project War Bird:
1971 Plymouth Roadrunner
383 4 speed with air conditioning
GY3 Curious yellow
All original
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Re: 383 vs. 440
[Re: CurYellowBird]
#266454
03/30/09 07:09 PM
03/30/09 07:09 PM
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Joined: Feb 2003
Posts: 3,691
MO
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master
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If you decide to do another motor.....Pick up a Mopar Action "mopar tech special" 1995 where they built a 451/400, 727, in a 72 RR with 3.23 gears. The car licked off a 13.50 in the 1/4. Car had huge amounts of torque. Fully loaded car with A/C. Cam was an MP 284/484 hydralic. You can find this on a CD too by looking at a link here on moparts. http://www.moparaction.com/Tech/archive/Beeper.htmlI don't know how much it would cost to build a stroker 451, but I'd think you could do it pretty cheap with the availability of 400's around and a good used 440 crank. I know there are some PURESTOCK guys running mid 13's with some 383's and 4.10 gears.
Last edited by cdp; 03/30/09 07:10 PM.
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There were other issues too, but this was the main one. Another rebuild later after listening to folks on here and getting more involved in the build and the car runs like a champ now.
