sport fury guy
New Member
I am rebuilding my 383 in my 67 sport fury plymouth, I want to increase the horse power to around 400 HP, I have the 383 commando which is about 330, what improvements should I make to get it to 400 HP?
Rebuilding 383 engine
- Thread starter sport fury guy
- Start date
1971 300 Alvah
Member
First...what is the budget?
Increasing the HP can cost a lot of money if you dont do your homework.
Asking here is a good start but will get many different suggestions.
You just have to pick what suits you.
I am leary of any camshaft/lifter kits on the market today.
Why?
As a victim myself too many camshaft/lifter failures rifht out of the box.
To make 400hp once you change one thing it can snowball from there.
New pistons for 383 are not cheap.
Then the rods and crank need to be balanced.. And so on.
Keep in mind in a big heavy car torque is what moves it not horsepower--which is gained on the higher end of the RPM spectrum.
Hope this helps and now let the games begin. Lol
Increasing the HP can cost a lot of money if you dont do your homework.
Asking here is a good start but will get many different suggestions.
You just have to pick what suits you.
I am leary of any camshaft/lifter kits on the market today.
Why?
As a victim myself too many camshaft/lifter failures rifht out of the box.
To make 400hp once you change one thing it can snowball from there.
New pistons for 383 are not cheap.
Then the rods and crank need to be balanced.. And so on.
Keep in mind in a big heavy car torque is what moves it not horsepower--which is gained on the higher end of the RPM spectrum.
Hope this helps and now let the games begin. Lol
sport fury guy
New Member
Thanks for the reply, I am looking to spend $4000 to $5000 if necessary, I was looking at purchasing a 2086 top end kit from Edelbrock which runs around $300, I would also purchase headers.
Luke Pokrajac
Active Member
Is the 383 an original h-code engine? You might just have zero deck pistons in it. How many miles on the engine? I love the 440 source heads and Lunati Voodoo cam I installed on my 68 h-code 383. It really runs awesome...and I didnt even touch the bottom end.
I just watched a segment of Nick's Garage where he got 400 horsepower out of a 383.
Is the reason for the rebuild to get more power or because "it's time"?
It seems that far too often, people get a horsepower figure in their head and head in that direction. As if that is the magic way to go. Something they can talk about at the local cruise events? ONLY thing is that in the current time, 400 horsepower is a stock V-8 . . . nothing special. Whereas in the later 1960s, 400+ horsepower was a Street Hemi, 2x4bbl Ford 427, or various flavors of other GM big V-8s.
In many respects, a "good street motor" will build a good bit of torque in the lower to mid-range rpm, yet have good enough heads, exhaust system, and carburetor size to "rpm" to 5500 or so without slowing down. It would be much better to aim for 400+lbs/ft of torque over that middle rpm range and then let the horsepower "happen". This should result in a car that will idle reasonably smooth witih the a/c operating in the dead of July, have good off-idle throttle response (which can make the car a joy to drive with no drama), have enough manifold vacuum to run the power brakes well, and not need a really special torque converter in the process. A torque curve in the 2500-3500rpm range, which will "GO" is more important than 400 horsepower that only happens at 5000+rpm, by a long shot. Then, if somebody might inquire about "How much power does that thing have?" Just reply . . . "I'don't know but it Goes Like Hell from 2500 to 5000rpm." By the same token, modern generations have become jaded by 707 horsepower factory Challengers and Chargers, so 400 horsepower is "nothing" by comparison. Build torque and don't get into the "bragging wars".
As far as parts and pieces, OEM-spec or better parts on everything. But don't head to "race parts", either! Tell the machine shop what you want and let them procure everything. Follow their advice, or at least consider it, too. Providing you find a good machine shop! Line hone to just touch things up, with a decking and power hone with deck plates. Bronze Heli-coil valve guides (stock Chevy 454 orange valve seals, trimmed to length), and "hard seats" can complete the valve job. Cleaning up the intake ports (as in NHRA legal) is always good, plus similar on the exhaust side. A good balance job works, too.
Lunati has some good cams, including one that is their modern interpretation of the Chrysler HP cam. I believe that another member in here has that in his '68 Sport Fury 383 (factory) 4bbl V-8. Summit sells it under their name at a good price, too. He likes it . . . didn't do anything to the bottom end or heads, either.
Many might like the Performer RPM intakes, but the normal Performer might be a bit better for a street motor, with few hood clearance issues, unlike the "RPM
intake which is taller.
When you go to talk to the machine shop, tell them what you are wanting to do and get a generalized quote from them THEN. Do NOT mention horsepower figures as that might send the wrong message to them. Do mention that you want it to last 100K miles instead, but run a bit better than stock. With a Cloyes roller timing chain, for longevity!
Just some thoughts,
CBODY67
Is the reason for the rebuild to get more power or because "it's time"?
It seems that far too often, people get a horsepower figure in their head and head in that direction. As if that is the magic way to go. Something they can talk about at the local cruise events? ONLY thing is that in the current time, 400 horsepower is a stock V-8 . . . nothing special. Whereas in the later 1960s, 400+ horsepower was a Street Hemi, 2x4bbl Ford 427, or various flavors of other GM big V-8s.
In many respects, a "good street motor" will build a good bit of torque in the lower to mid-range rpm, yet have good enough heads, exhaust system, and carburetor size to "rpm" to 5500 or so without slowing down. It would be much better to aim for 400+lbs/ft of torque over that middle rpm range and then let the horsepower "happen". This should result in a car that will idle reasonably smooth witih the a/c operating in the dead of July, have good off-idle throttle response (which can make the car a joy to drive with no drama), have enough manifold vacuum to run the power brakes well, and not need a really special torque converter in the process. A torque curve in the 2500-3500rpm range, which will "GO" is more important than 400 horsepower that only happens at 5000+rpm, by a long shot. Then, if somebody might inquire about "How much power does that thing have?" Just reply . . . "I'don't know but it Goes Like Hell from 2500 to 5000rpm." By the same token, modern generations have become jaded by 707 horsepower factory Challengers and Chargers, so 400 horsepower is "nothing" by comparison. Build torque and don't get into the "bragging wars".
As far as parts and pieces, OEM-spec or better parts on everything. But don't head to "race parts", either! Tell the machine shop what you want and let them procure everything. Follow their advice, or at least consider it, too. Providing you find a good machine shop! Line hone to just touch things up, with a decking and power hone with deck plates. Bronze Heli-coil valve guides (stock Chevy 454 orange valve seals, trimmed to length), and "hard seats" can complete the valve job. Cleaning up the intake ports (as in NHRA legal) is always good, plus similar on the exhaust side. A good balance job works, too.
Lunati has some good cams, including one that is their modern interpretation of the Chrysler HP cam. I believe that another member in here has that in his '68 Sport Fury 383 (factory) 4bbl V-8. Summit sells it under their name at a good price, too. He likes it . . . didn't do anything to the bottom end or heads, either.
Many might like the Performer RPM intakes, but the normal Performer might be a bit better for a street motor, with few hood clearance issues, unlike the "RPM
intake which is taller.
When you go to talk to the machine shop, tell them what you are wanting to do and get a generalized quote from them THEN. Do NOT mention horsepower figures as that might send the wrong message to them. Do mention that you want it to last 100K miles instead, but run a bit better than stock. With a Cloyes roller timing chain, for longevity!
Just some thoughts,
CBODY67
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sport fury guy
New Member
Hey everyone, you have given me some great ideas, my son and I are doing this as a winter project. I want my car to go faster than it does now, but not stupid fast, and make it look nice. My son is the mechanic, and I know old cars, so we should make this work well. If more ideas, keep them coming.
Luke Pokrajac
Active Member
My man C-body always has some excellent comments. You have a heavy car...build it for torque down low. It will really, really get off the line nice. New cams are quite a bit advanced over the old grinds...especially the original equipment stuff. I've been happy with the 256 lunati voodoo in my 383. It is a modern fast ramp cam like the comp XE's...but it tends to set the exhaust valves down a little easier...almost stock according to lunati. I tell ya...I now have overdrive in my four speed fury and it can take a 6% grade hill at 75-80 in overdrive (2.58) final gear ratio...without going into carb secondaries. These new cams really pull that well down low in the rpm range. The 440 source heads just made it better with quench and a closed combustion chamber.
My 383 cylinders were eggo so it had to be bored .40 over. New pistons and machine shop time ate up the majority of my budget.
This is what 6 grand CDN looks like in a well built 383..
This is what 6 grand CDN looks like in a well built 383..
69CoronetRT
Senior Member
People always respond with the How but rarely ask the Why?
What is the additional 70 horsepower for?
What will you be doing differently with 400 horse that 330 won't accomplish at a much cheaper rate of return and time?
What will the 70 HP do to enhance taking the kids/grandkids out for ice cream on a Saturday night or parades?
Most people think they need to chase HP instead if increasing torque.
If the purpose of the effort is just a target number to say you have 400 horse, then it's actually simply for bragging rights...that's OK but will any additional trade offs or compromises allow you to enjoy the car more? (Do you really want to be tweaking carb jets for maximum output?) Chasing HP is more about measured performance (top end) than effective use.
If the reason is to get a heavy car up to speed quicker (acceleration and 'seat of the pants') then you want to be looking at how to generate additional low RPM torque, not HP.
This is easily, and far more cheaply and reliably, accomplished by changing gears with a ratios say between 3:55-3:91 (all factory offerings).
If a rebuild is in order, there are a lot of cams designed to increase low end torque.
Intake manifolds designed to assist low end torque are available.
Consider what you want to accomplish and why you want to do it before spending money on ineffective and expensive items that are contrary to your goals for application. Make all of the components work together.
EXACTLY!!
Yes things need to work together. You haven’t added any ideas on what your are going to do with the car, what will be max rpm/ speed.
Some things are not helpful, like a high volume oil pump. Seldom necessary on a street driven car:
Takes more power to turn
Can break the pump drive
adds heat to your oil
Slows the car down.
Some things are not helpful, like a high volume oil pump. Seldom necessary on a street driven car:
Takes more power to turn
Can break the pump drive
adds heat to your oil
Slows the car down.
I have the Melling standard pressure-high volume pump
Been driving the **** out of my car since 2017.
No issues with the pump.
I have heard there were issues with the high pressure-high volume pump, however.
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Chrysler 383 Engine Buildup From The Bottom Up - Mopar Muscle Magazine
383 Engine Restore - Tech Articles - Mopar Muscle Magazine
Classic articles on this topic
383 Engine Restore - Tech Articles - Mopar Muscle Magazine
Classic articles on this topic
Those who always hate on headers and big carbs will see that the engine made more peak tq at a lower rpm with the mods vs stock.
If they had used an Eddy rpm perf manifold you'd have exactly what I'd suggest, you don't even have to open the engine up
If they had used an Eddy rpm perf manifold you'd have exactly what I'd suggest, you don't even have to open the engine up
oldkimmer
Active Member
U may not need more hp or tq if u get a converter designed for ur car. PTC, Ultimate or Dymamic make the best converters available. The tq multiplication from a well designed converter will be the single best upgrade u can do to ur car. Far ahead of 70 extra hp. Kim
1970FuryConv
Old Man with a Hat
Thanks for the articles.
I agree with a lot of what they had to say. I like 9.2 compression with iron heads. I have good experience with the Keith Black hypereutectic pistons.
On the Demon carb, I had 1900 625 cfm on a 1973 360. I found the car hard starting. Then a pin fell out of the choke and the throttle blades stuck open half way. I was idling at 3000 rpm. Maybe I just got a lemon, but I was angry with Holley for poor design/assembly. Needless, to say, the carb is no longer on my car.
Also, I have had good experience with Hughes Engines cams, especially in the seat of the pants judged torque improvement.
Alchemi
Member
Just putting it out there, but...
A 496 bottom end kit from 440 source is only $2400 - you may be able to achieve it cheaper with a mix of other components bought piecemeal, depends on your procurement skills and what your local balance shop charges.
You would not be able to swap another thing out to get similar results for $$ spent - of course the heads will need a build and a bunch of other stuff that will probably still land you in the $4k+ region, but heads n cam to get to a similar power level would make a more wild race style motor than what just upping the cubes will do - the cubes will give you the torque that you actually need.
It also would be up-gradable with heads, exhaust etc at a later stage as desired.
A 496 bottom end kit from 440 source is only $2400 - you may be able to achieve it cheaper with a mix of other components bought piecemeal, depends on your procurement skills and what your local balance shop charges.
You would not be able to swap another thing out to get similar results for $$ spent - of course the heads will need a build and a bunch of other stuff that will probably still land you in the $4k+ region, but heads n cam to get to a similar power level would make a more wild race style motor than what just upping the cubes will do - the cubes will give you the torque that you actually need.
It also would be up-gradable with heads, exhaust etc at a later stage as desired.
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