Building a 525+ HP / 550+ TQ 383: What's Needed??

[Road_Runner]

If I can hit the 525-550HP / 550+ TQ target, I think I'm going to stick with the 383 in my Roadrunner and forego the stroker Hemi I was thinking about.  I've got some base parameters that the 383 / 383 stroker has to meet:

- 70 383 HP block
- like the way 383 revs, but if a stroker is needed would like to stay away from extremes / something like 438 preferred
- Six Pack Intake & Carbs (only performance intake that works with the airgrabber on the car)
- aluminim heads (thinking Indy, ruled out Stealth heads if they're really made in China)
- TTI or some other large diameter headers (already dreading spark plug changes)
- Electronic Ignition, has Mopar conversion setup now but would change if needed (MSD 6AL maybe?)
- must run on Premium pump gas which is mostly 93 octane around here
- strongly prefer hydraulic cam but expense of roller cam OK if needed to reach HP/TQ targets
- motor needs to look externally like it could have come out of 70's (I ran a 6pack back then so for me at least this combo is correct)
- plan for rest of car is 4 speed & relatively steep 3.91 to 4.30 rear & likely an overdrive of some description (Gear Splitters?)

Well, based on some of the articles I've read although agressive my target should be doable.  What do you think?  I'm especially interested in what those of you who build engines think as you would not only know what it takes, you might be able to give me an idea of what the machining should run me if you were doing the build.  Who knows, if you're not too terribly far away you might be!!

Thanks in advance, Jim

[Supercuda]

That's a pretty tall order for a stock-stroke 383. As a stroker, it would be easier to hit the goal, and you would have greater driveability. Either way, a roller cam will give the best result, allowing you the power production with a little less overlap and duration. If you don't mind a peaky engine, you can do this with the stock stroke and a flat-tappet camshaft, but it would be a beast to live with. The torque goal will be difficult to obtain with the stock stroke (maybe nearly impossible), although you will see lots of torque with whatever you do. Just don't be surprised to find out that you won't see the huge numbers until you see some pretty high rpm. Also don't forget that it's not just about how much air you flow; it also needs to have good QUALITY of airflow. If you stay small-displacement, you will need to concentrate a lot of effort on cam lift vs.airflow. Intake manifold selection will become more critical, too.

[Road_Runner]

That's a pretty tall order for a stock-stroke 383. As a stroker, it would be easier to hit the goal, and you would have greater driveability. Either way, a roller cam will give the best result, allowing you the power production with a little less overlap and duration. If you don't mind a peaky engine, you can do this with the stock stroke and a flat-tappet camshaft, but it would be a beast to live with. The torque goal will be difficult to obtain with the stock stroke (maybe nearly impossible), although you will see lots of torque with whatever you do. Just don't be surprised to find out that you won't see the huge numbers until you see some pretty high rpm. Also don't forget that it's not just about how much air you flow; it also needs to have good QUALITY of airflow. If you stay small-displacement, you will need to concentrate a lot of effort on cam lift vs.airflow. Intake manifold selection will become more critical, too.

Beast to live with sounds like the current engine!  Seriously, my criteria to the speed shop that helped build the motor back then was that I had to be able to drive it on the street, but only just barely.  They hit the mark as it outran a lot of cars no one believed a 383 could back then.  I'm OK with the 438 stroker but much bigger and I'm going to second guess starting with a 383 I think.  And because I'm fixed on using the airgrabber setup, its got to use the six pack intake so that could be a limiting factor at some point.

Thanks, Jim

[Supercuda]

The current thinking is to build more cubic inches, so you are in a definite minority (I'm there with you!), but compared to OE engines, the 6.5 liters of displacement that we're talking about, is HUGE! On to brass tacks: If you want this to spin like it did before, forget about a stroker. Also, keep in mind that smaller displacements don't require as much port cross-section to achieve the same flow as a large displacement engine. With unmodified 346 castings, my 383 makes 470hp through an M-1 singleplane and cast-iron HP exhaust manifolds. Decent heads and good headers should meet your hp goal, but the torque might not make it to 550 lb/ft. Displacement would be the limiting factor, here. Cam duration should be pretty high, even with a roller cam, and valve lift will need to be between .550" and .650". Using the six-pack induction will give you the needed fuel and air, and compression should be about 10.5:1 with iron heads, or about 11.5:1 with aluminum. This will support premium pump fuel.

[Chryco Psycho]

I agree that looking into a 440 crank 438 CI is a great route to go with the 383 block

[70_Hemi_Cuda]

I have a 1970 383, 10.1 w/915 heads. Comp Cams XE 286-296 HL .545 cam, roller rockers, as of right now a edelbrock intake, 850 holley, and it dyno'd 480 hp. I'm changing the setup now and going for more power but this gives you an idea of what I got with my current combo. Unfortunately for me I have to go with a low rise intake due to my shaker hood setup. GL with your build!

[Cooter]

Well, there's always the old stand by when you just don't have enough cubes..........N.....O.......S

[Road_Runner]

The current thinking is to build more cubic inches, so you are in a definite minority (I'm there with you!), but compared to OE engines, the 6.5 liters of displacement that we're talking about, is HUGE! On to brass tacks: If you want this to spin like it did before, forget about a stroker. Also, keep in mind that smaller displacements don't require as much port cross-section to achieve the same flow as a large displacement engine. With unmodified 346 castings, my 383 makes 470hp through an M-1 singleplane and cast-iron HP exhaust manifolds. Decent heads and good headers should meet your hp goal, but the torque might not make it to 550 lb/ft. Displacement would be the limiting factor, here. Cam duration should be pretty high, even with a roller cam, and valve lift will need to be between .550" and .650". Using the six-pack induction will give you the needed fuel and air, and compression should be about 10.5:1 with iron heads, or about 11.5:1 with aluminum. This will support premium pump fuel.

I appreciate the info, especially since your 470 hp number shows that I'm not too far off since better heads and Hooker Super Comp or TTI headers are definitely in the plan.  I realize the 550 TQ is probably more likely with the 440 crank, but I'm just curious how close I could get with the 383.  Thanks for the help.

Jim

[Road_Runner]

I agree that looking into a 440 crank 438 CI is a great route to go with the 383 block

Any other specifics you can share?  I know 440Source sells a kit but based on what I want I probably will need to piece together my own 'stroker kit' with even lighter parts, more compression, etc.  Also, I know you do a lot of builds yourself so any advice would be greatly appreciated including the name of an excellent Mopar engine builder within driving distance from Atlanta, GA.  Other than the 6 pack & 70's period correct appearance I'm open to whatever options get me a stout dependable street motor. 

thanks, Jim

Thanks, Jim

[Road_Runner]

I have a 1970 383, 10.1 w/915 heads. Comp Cams XE 286-296 HL .545 cam, roller rockers, as of right now a edelbrock intake, 850 holley, and it dyno'd 480 hp. I'm changing the setup now and going for more power but this gives you an idea of what I got with my current combo. Unfortunately for me I have to go with a low rise intake due to my shaker hood setup. GL with your build!

Thats real close to what I have in the 383 now including a very low Mopar M1 Dual Plane intake so the 4 bbl air cleaner fits the airgrabber hood seal.  You'll likely finish yours before I start mine as I'm just starting may parts gathering phase and wanted to know that my plan would work before buying any more parts.  Please share with us the results of setup changes as I'd love to copy the success of others and do it once.

Thanks, Jim

[Road_Runner]

Well, there's always the old stand by when you just don't have enough cubes..........N.....O.......S

And I guess I would consider an NOS setup, but its not my first choice.  In fact, Georgia passed a law recently that even having NOS hooked up on your car is now illegal with all sorts of bad things that will happen if you're caught.  What's stupid is that other power adds like turbos & blowers are perfectly legal so not sure why NOS is being picked on.....Plus, I admit to being a little old school when NOS was commonly called 'cheater gas' around here.  So naturally aspirated would be my preference for this build, but say I got a new Challenger, I would so put on one of the custom blower setups available that push either the 5.7 or 6.1 to over 600 hp.

Later, Jim

[Chryco Psycho]

the 440 crank is the way to go , you maintain rod ratio using 440 rods but lighten the rotating mass by about 7 lbs using lighter shorter pistons & removing weight from the crank to balance the assy , it will rev faster & increase ttq substantially

[Road_Runner]

the 440 crank is the way to go , you maintain rod ratio using 440 rods but lighten the rotating mass by about 7 lbs using lighter shorter pistons & removing weight from the crank to balance the assy , it will rev faster & increase ttq substantially

So do I need to just buy a 440 crank and have it turned down to fit the 383 block or would you recommend any particular vendor's?  And stock 440 rods or someone's I or H beam 440 rods?  I plan on turning as high rpm as the engine will allow so don't mind putting $$$ where it counts to make the motor more durable.  I don't build engines myself so I'll either need to get a kit or know all the details about what parts I'm gathering, or I'm sure to screw it up and waste money or worse if the wrong parts get into my engine.  This is where a 'local' engine builder would be real nice to work with. 

Thanks, Jim

[Supercuda]

Whichever course you take, the H-beam rod is a better piece for what you're doing. Don't skimp on pistons, either; only go with a quality vendor you trust. A light stroker assembly will bring the "spin" back into low-deck territory, and probably make you happier than using a "standard" stroker assembly.

[Chryco Psycho]

There are a few vendors for stroker kits , 440 source is one , use a bolt in crank , H beam rods & a premium forged piston . 440 Source has the kit with rings & brgs for $1800