What 383 combo for 400 - 450hp streetable?

[QUADDAK]

I have talked to you guys before about the 383 I bought and is currenlty rebuilding for my 73 challenger. I would like to run about 400- 450 hp. This may eventually be my daily driver. I have already started getting parts together but nothing is set yet. Some of the parts are listed.

Car:
73 Challenger Rally with 489 3.23 SG, 727 slap stick, 2800 stall.
PS, PB, AC

Engine:
383 stock bottom end (from a 70 plymouth cuda), steel crank, stock standard size pistons and CR.

Either 452 or 906 heads, large 2.14 1.88 SS Manley high flow valves. Plan on doing an extremly good port job on the heads.

Hedman 1 7/8 headers, dual exhaust with crossover and flowmasters, stock tips out the back.

Currenlty have a dual plane Edelbrock Performer RPM with street a Holly avenger 770.

No cam selected.

What combo of parts would get me the desired HP from the 383?

Anyone out there with a 450hp street 383 that can communicate the combo?

Thanks!

[custom880]

Well you are definately on your way. You have a good start with some great parts. I am currently building a 500 HP 400 motor. I will use the RPM manifold, and 452 heads but the 906's are great also. I have gone with KB pistons that are 30 over (the block needed it) and Eagle rods (not needed but I wanted them). I have a set of sealed power molly rings, full grove bearings. The crank main was ground .20 and the rods .10, all needed. The cam that you should look into is a Racer Brown cam. Call them up and tell them what you want to do and they will set you up with a great cam selection. make sure that your pistons come up to as near as .000 as possible. As far as carb is concerened, either a Edlebrock (850) or Demon is what I am looking at. The motor will be streetable and really fly at the track. I am probably missing something here, but thats it off the top of my head. In a Challenger you should do below 12 at the track. The 383 is a strong motor and you should be real happy with it.
Bob

[b-1ken]

You might consider a turbocharger. Lots of power AND driveability. Good gas mileage (if that's possible with a 383) too. It's not as difficult to do this as one might think.

[SweetGT]

ken,

I am building a 360 for my 65 dart gt as soon as I get out with my degree. My dad and I are going to build it. I was wondering(because of your turbo comment) if you know anyone who makes a kit for mopar engines at all. I was planning on putting in twin turbo, but a premade kit with all piping, intercooler, wastegate, bov, etc would be really nice. Also have you done an install of a turbo on a carbed engine? I have a tough time finding anything about this topic because most people build mopars with 440's and just stop there, never look at turbo or supercharging. I am planning on getting 600-700 hp out of the motor, and I figure with 12-15 psi boost I would be at that number with a fairly mild setup on the engine itself(I think that would need to be a 350-400HP engine without turbo). If you have any insight on this it would be great.

Stephen

[b-1ken]

I have virtually no experience with turbo's but an ex student of mine put one on a big block 454 Chevy and it was so simple and worked so well that I thought more people should do it. He "borrowed" a turbo from a Mack truck and blew it through a 850 Holley. They (he and his brother) fabricated the duct work in their back yard with a home welder. Neither of these guys have any formal education with regard to turbo theory. They just made up the required pieces and experimented with it. I got a ride in this car (4000 lb Malibu with 3.70 gears) and that thing could blow the tires off the car with a hit on the throttle at 50 mph. He had a very small hydraulic cam (shook a little at idle but no rump-rump). I have ridden in a few fast street cars before, but this one impressed me the most because of it's power AND streetability.

[SweetGT]

Yeah it is really hard to find literature on turbo'ed carb'ed engines. Sometimes I think it might be easier to get a fuel injected car and get a end user computer that would be able to pull timing as needed, and adjust a/f ratio and all. I think the problem with that would be all the minute functions like cold start and stuff like that. But I guess I will see when the time comes. I was thinking about maybe borrowing a good sized block from a fuel injected turbo car and just piggy back the ecu to change the stuff I want to change. But the problem I find there is getting the right size engine for my power needs. Well thanks for the reply.

Stephen

[ehostler]

If you do a search, you will find info about converting to turbo.

If you don't want to mess with the exhaust system, you can get a procharger. It's belt driven instead of exhaust driven. There are a couple of companies that have procharger kits. Do a search for procharger and you will find more info.

[ehostler]

I forgot to mention. For heads, either go with the EB aluminum heads or Hughes Engines is about to start selling a new aluminum head that is far superior to the EB head for $2,200.

[71383bee]

quad,

Definately go with better than stock pistons. The KB's are good pistons. Surprisingly the 383 has relatively low compression. You need to be in the 9.5:1 range to run 92 octane so be sure to measure your compression depth, gasket thickness, and head cc's. 906's and 452's are open chamber designs so they have a lot of room. It is probably a good idea to deck the block to zero and adjust compression with your choice of head gaskets.

Racer Brown is a good choice. I am happy with my Comp Cams cam and they do grind cams for a mopar lifter, but you have to request it.

As for the valve train the stock rocker shaft style can take a lot of abuse and should work fine for what you are after. The rollers are nice, but the cost is very high and the gains are slightly minimal on lower hp engines.

I would not be so eager to put in the larger valves. I have heard from alot of the motor builders on here that larger valves can actually hinder the engine's performance. I would definately ask around before you decide to put in larger valves.

I have a similar combo except I am running a performer intake. I want to switch to the RPM when i get some more time and funds. I also have the 770 Holley, but I wish I went with a Demon. The carb is good, but I think it is a bit too much for the engine. Believe it or not I think a 650 mech secondary Demon will really wake my combo up! Bigger ain't always better!

[b-1ken]

Sweet: What I was trying to get across was that YOU could do what these guys did with the turbo. As I said, they simply blew the turbo through an almost stock 850 Holley. They just put a bonnet on top of the carburetor and connected it to the output of the turbo. They fabricated the exhaust system to go from both exhaust manifolds to the turbo with a waste gate. They set the waste gate to open at 14 psi boost. If you're interested, I may be able to get in touch with the guy and take some pictures and get some info as well. Believe me, these guys aren't rocket scientists. They were determined though.

[SweetGT]

Ken,

I found some stuff online about turbos. I saw the bonnet idea and that looks like a reasonable setup. I am pretty familiar with turbos but just not on carbs like I said. Does anyone know how difficult it would be to do EFI, I am just wondering what kind of computer I could run to control all the small things, like cold starts and stuff. I can deal with pulling the timing, adjusting injector pulse width and stuff. But I would need a computer that is going to be end adjustable. Any help with this. I will do a search too and see if I can find anything on it.

Stephen

[b-1ken]

There are a number of laptop progammable, stand alone, EFI units out there. A couple of my students bought one from Haltech, but I wouldn't neccessarily recommend it. It can be pretty costly by the time you buy all of the hardware. The carburetor route is cheap and easy and you won't have to spend months programming it.

[gt68]

for that EFI thing you should really look into megasquirt www.bgsoflex.com/megasquirt.html and the discussion forums, cheap and very effective.

[23T-Wedge]

SweetGT,

If you ever lurk over on the Hemi's and NHRA thread, you might send a post to Hemifred, he's running a 190mph Roadrunner, using a lot of relatively inexpensive and easy to find turbo parts (at least I remember him saying that in a post onetime) and fairly small cubic inches, by todays mega-motor standards anyway. I know he's at the Funny Car Reunion in E-town this weekend, but he comes in and out of this board pretty regularly, believe he could give some pretty good insight if you're really interested in the turbo route.

[QUADDAK]

71383bee, you are right on concerning the CR. When pulling the engine down I failed to check the piston depth to calculate the CR. What I might do is mock build the bottom end and see what the actual CR is then go from there. My orginal plan was to build the 383 back as stock and work on my 400 stroker. That is one of the reasons for wanting to save a few bucks and use the stock pistons. What did the KB cost you? This project has taken me so long as it is there's no telling how long it will take me to complete the stroker project.

I was also concerned with the larger valves reducing the velocity and hurting the power. I was going to use the valves with my stroker motor and had them laying around so I thought about using them. I only paid 106 dollars for them.

Thanks for the input. How do you think the larger valves will work with good port job on the 452's, Hughes or racer brown cam, and the blueprinted CR?

I did checked on the prices for the Racer Brown cams and they are the same as the Hughes so I may just go with them.

[71383bee]

The kb's were in the $200 range if I recal. I don't remember exactly because they were lumped in with the costs of the motor. They are reportedly good units. I never zeroed my deck which I wish I did so I had better control over the compression height. If you are building a stroker 400 then I would sugest using building the heads for that and temporarily using them on the 383. I think the larger valves will kill a little of the bottom end, but on the 400 stroker those valves would probably work great. So I would build the heads for the 451 and use them on the 383 to get by. Then when the 451 short block is done just swap on the heads and your set. The only thing is the difference in cams between the two motors might require you to swap springs.

For a 383 your suggested combo sounds awesome and it will have decent street manners too depending on how radical of a cam you go. My car has excellent street manners and it has plenty of go too. I need to throw on that RPM intake and that will really wake it up. I also would suggest a distributor curve from cuda.

I think I probably have too much head flow, but I too am planning on a 451 and these heads will go on that motor.

[chicken_polo]

call up scott brown at straightline performance and tell him what you need for a cam. hell treat you right! i think its www.straightline-perf.com but i may be wrong

[23T]

My $0.02 if you are going to boost the engine go with a blower and pull it through the carb, psi the inside of a card tends to lead to problems and a box to # the entire carb has problems holding the boost

[b-1ken]

Originally posted by 23T
My $0.02 if you are going to boost the engine go with a blower and pull it through the carb, psi the inside of a card tends to lead to problems and a box to # the entire carb has problems holding the boost

I would have agreed with you until I saw this guy's car with the blow through set up. They made there own bonnet (did not enclose the carb in a box). They used a pressure balance tube at the throttle shaft. Also they built a dam where the air blew into the box so the air didn't blow over the top of the carb. This car ran REAL well part or full throttle. If you had a backfire with the pull through type of system you would have one BIG boom.

[dartsport1974]

back onto the turbo commencts there is a book sold on ebay that I'm almost half way through and it's a great book. The cam on a blown engine you don't want to be much 'bigger' then stock and you want low comp. like 8:1 is the most commonly used and generally most ideal. Also the book I listed above deals with blow through setup for the most part and is great for the old carb setups. Also forgot which mag it was but they did a side by side test of belt driven turbos, blowers, and then plain old fashion turbos and the plain turbo blew the others away. Since you'll have headers you can run a sequential setup (one small for quick boost and one larger for the larger psi) Also unless you get some really good heads you can actually just run 2 smaller setups and run around 11lbs of boost for boost response as fast as a blower. Just a suggestion and yes the power gained from this would be massive. 150 to 200 horse and torque. just a suggestion. also tubos can be found on ebay cheap.

[71383bee]

Why don't you guys go start your own turbo's and superchargers rule post because all I understood from the original poster was what tips to increase the performance and efficiency of a 383. Specifically he was looking for piston, cam, intake, and head recomendations.

Seriously is ...put some boost in there... the answer to every motors needs! Gosh darn i hate going to shows and seeing all sorts of crap hanging all over the motor!