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why do people think 500hp from a 383 is IMPOSSIBLE to reach?

8K views 100 replies 16 participants last post by  1Gary 
#1 ·
Why do people think 500hp from a 383 is IMPOSSIBLE to reach and can't be done? I see 383s going 500hp - 580hp ... though I know it starts to take away from streetability. .. so my question is ... what is the max power level for a 383 and still maintain streetability. ... not a daily driver though....
 
#2 ·
Depends on a lot of variables. What do you call streetable? Friend of mine has an 850hp NA 1100hp on spray mustang that he calls streetable. Personally if you can sit in traffic without it overheating and take off easily without spin I'd call it streetable. For that I'd say 6-650 hp would probably be as far as I'd go and call it a street car for an NA ride. You can always spray the hell out of it for the extra go fast if you feel the need.
 
#6 ·
I currently have a complete vortec engine in my garage that is destined for the 500hp mark NA and a 650 on spray. Basically what I'll be doing is using the stock heads and block. The heads will be angle milled 1* and the intake ports cleaned up and some blending with bigger valve, the exhaust ports will be reworked completely. Full roller rockers and an appropriate intake and cam. Compression will be in the 12:1 region. The block will be half filled and mains will be splayed with a good fully balanced rotating assembly. I feel confident when I'm done I should be at 500 or damn close to it. I'm hoping to keep it looking like a stock engine with an intake headers and to big of a cam so very little pretty shiny stuff. Gonna paint it all black to try and keep it from looking more than just backyard modified so to speak.
 
#7 ·
this is a video of a members 383, It has a flat torque curve,solid roller cam,210 cc heads, makes 500 hp, will rev past 6k willingly. Just add more compression and a bigger cam and this engine made 579 horse power,,,

the flow numbers Richard posted on the Speir heads,shows great potential for a 500 plus horse power sbc. How mild of engine do you want? Use a 220º duration cam and make 450 horse power very easily!
https://www.youtube.com/watch?v=ISoCPlww-s8
Last edited by vinniekq2; Today at 12:47 AM.

post I just made on another thread
so my answer is at least 579 hp and street able
 
#10 ·
Wow.. the reason I inquired is because I was shopping around for a transmission and one of the builders asked what do I have... I said 500hp 383.. and he said thats pretty stout...are you sure its 500hp?????

LOL. now I know some people who might cheat or OVER estimate their numbers but...ive seen in magazines..on different forums..and even on joe Sherman... proformance. .engine factory... where they build 500hp engines so I know it is POSSIBLE!
 
#16 ·
Well I'd say you're reading too much into his response. I don't think he was indicating it wasn't possible. Just asking if you were really sure you had that much HP. I question in my mind whenever I hear someone say they have 500 HP, in a SBC. Not because it isn't easily accomplished, but because I hear far more people quoting the figure, than really have the figures to back it up.
I think he just wanted to be sure you had that much HP, before building a trans to handle it.
 
#12 ·
there's cam only 350ci LT1's that get close to the 500 flywheel hp number. Stock engine, full bolt ons, and a cam. Stock heads, pistons, intake, gaskets, the works.

So why would a 383 surpassing that with all sorts of aftermarket goodies be a surprise? I'm sure someone around here has crossed 600hp with a 383 on pump gas- keep in mind though this isn't cheap and is riding the razors edge for "pump gas". The parts availability and engine modeling available today makes these fantastic power numbers attainable. The technology you can put in your street car today surpasses the best racing parts available back in the 70's.
 
#13 ·
The parts availability and engine modeling available today makes these fantastic power numbers attainable. The technology you can put in your street car today surpasses the best racing parts available back in the 70's.
So true man. These days we have cool company's like CHI, Trick Flow, AFR, AFD, Raptor and that's just of the top of my head, Edlebrock make cheep awesome heads these days too! I have even seen Pro Comp heads fully flowed and and better valves and springs make close to the 600hp mark! So yeah awesome what computer power does for us these days!
 
#17 ·
demarques_191
from what I remember you went a little light on the cam specs and we figured 475 ish?
My limits are 1.5 horse power per cubic inch for a nasty street engine. This is street able but not always as well behaved as a moderate performance car. We are talking solid cam and large carb engines that come alive from 4-7000 rpm,,,, I dont see many engines making 1.5 hp/cube using a hydraulic cam/small carb or anything but great quality ported heads
except AP72's LT
 
#21 ·
it wasn't my LT1, but many HR swapped LT1's are around the 450 flywheel hp mark and a few SR swapped LT1's get very near the 500 mark- on stock long blocks.

Swap the intake manifold and I wouldn't be surprised to see the same with Vortec 5.7l engines.

Its a damn shame the Vortec engine got such a poor intake manifold, even with its mild compression it had a lot of potential as far as engines for that time went. We're well past that now, but you have to pay new aftermarket prices for it- you can still find running vortec engines for $500.
 
#22 · (Edited)
The manifold vacuum is not needed for racing but... Ever notice that manifold vacuum covers for the varying throttle response needed in everyday driving. I did.

Even boost will not add the part throttle atmosphere.

So these are what, master tuners driving these around all fine. Nah, they drive like drag race cars. Know it.

People do it all the time, those kind of people, but people.

Look at the cars with camber problems and driving around with the boom stereo going , sos they cant hear the wheels hitting the fender lip.. I don't get the lower lower thing or the boom boom stereo thing. The Boom Boom music is one note at a sub frequency to provide a maximum hit. Sos it is not music. I play every instrument , and see the idiocy, so I usually nod and walk away.

We lowered the cars so they looked cool, performed better. Now you see them and the car cannot cross a parking lot with 4 people. They lowered them so much the geometry doesnt work and they handle worse .

We added a sub to our car or home theater to smartly add bass to the field. Somehow as things progressed they stepped away from quality sensitive materials and switched from paper to plastic for durability. So it can take more hits. The end result was crappy sound. They invested in it cause you bought it, now enjoy. What sounds better Kevlar or silk...
 
#23 ·
The manifold vacuum is not needed for racing but... Ever notice that manifold vacuum covers for the varying throttle response needed in everyday driving. I did.

Even boost will not add the part throttle atmosphere.

So these are what, master tuners driving these around all fine. Nah, they drive like drag race cars. Know it.

People do it all the time, those kind of people, but people.
babelfish couldn't translate this to english, can you try to?
 
#27 · (Edited)
Ap, It seems in some cases things obviously are not being made better.

I think more attention needs to be spent on making things better. Transmissions need more gears, paints need to evolve, materials, entertainment needs to improve ( not just dumb *** worship)etc.

Manifold vacuum, seems to be important in driving around, a carbureted vehicle.

What do you want to discuss exactly?

Going lean because you ran out of manifold vacuum during variable throttle conditions? Now the engine is lugging in a low rpm with no momentum, no stall, or pump shot. I think I am describing it correctly.
 
#29 ·
Ap, It seems in some cases things obviously are not being made better.

I think more attention needs to be spent on making things better. Transmissions need more gears, paints need to evolve, entertainment needs to improve ( not just dumb *** worship)etc.

Manifold vacuum, seems to be important in driving around, a carbureted vehicle.

What do you want to discuss exactly?

Going lean because you ran out of manifold vacuum during variable throttle conditions?
Since its Friday and after 12:00 in most of the country I'm going to assume you're "celebrating the weekend" early. This is a lot less coherent than most of your postings.
 
#31 ·
You guys were talking about transmissions , and big cams , and 4-7000 rpm powerbands on the street...

It does not fit?


Okay.. I still dislike the new entertainment, same old transmission selection , driving around cams for 4-7000rpm in daily traffic..
 
#40 ·
A g note cannot buy enough parts to make 500 hp,simple as that. headers are $500.

used engine $300,,,not likely
used cam and springs $200.. maybe
Used headers $200,possible
what do you do for computer correction?
$300 left gets you to maybe 350 hp with out tuning
maybe 425 with extreme tuning

seriously,wheres the power coming from?
used nitrous system?
 
#41 ·
A g note cannot buy enough parts to make 500 hp,simple as that. headers are $500.

used engine $300,,,not likely hot
used cam and springs $200.. maybe
Used headers $200,possible mighty warm
what do you do for computer correction?
$300 left gets you to maybe 350 hp with out tuning
maybe 425 with extreme tuning

seriously,wheres the power coming from?
used nitrous system?
seems some areas ls engine people claim it get them for 200-400 and of course they are fully dressed , they are 700+ for anything worth wild here..
headers if you can weld.. would be cheap..
computer, there was ls edit, don't know of that's just ls1 or..
most that junkyard dump a 4.8/5.3 in a car hang a e bay turbo off it..
5.3's with under 80k are 700+ no ac compress, p/s pump or alt, those are extra..
but some seem to trip over ls 5.3's for 2-3 c-notes.. whole works harness and ecu included..

if I ever do an ls take out it'll be 6.2 all alum.. if I'm going to swap to that family that require new everything(mounts, transmission or adapter,exhaust,fuel system,wiring) I'm going for the most cubes I can get while taking as much weight off the nose as I can..

god bless those in area that can get them for silly cheap and legally, not gonna happen here..
 
#45 ·
Got an example for y'all. This is my plan. 5.7 vortec complete for 40 bucks. Sold intake for 40 so now I'm at 0. Heads angle milled 1* and 202/160's put in 750.00. Most of that was buying the valves because anything worth doing is worth over doing. Ported exhaust myself and blended bowl area of intake and unshrouded both valves myself so 0 for that. Ls6 springs and trimmed valve guides myself 70 for springs. Comp retainers and factory locks don't remember but we will say 75.00. That brings it to 895 in the heads. Now, if I were to buy a used roller cam for 100-150 for a verified good cam and put this on the stock short block it should be over 450 as it is. 0 for the headers because I already have those and they came in the vehicle this will be going in once I'm done. Was give. The carb manifold by a friend of mine who ended up with it on trade and have enough carbs to outfit a dozen engines.
This will be 383 fully forged full roller when done but with the parts I have now it should be able to make a realistic 450+/- hp and have manners. Point is there's 450hp for under 1k......barely. I know my situation is my own and everyone won't have or find the parts I have or have found for the prices I've found them nor can/will everyone do their own port work no matter how mild it may be. All I'm shooting for myself when this is done is 500hp NA and 650-700 on the bottle and still look as dogish as possible. A sleeper of sorts. I'm hoping I can hit the mark for less than 3500-4k
 
#51 ·
Got an example for y'all. This is my plan. 5.7 vortec complete for 40 bucks. Sold intake for 40 so now I'm at 0. Heads angle milled 1* and 202/160's put in 750.00. Most of that was buying the valves because anything worth doing is worth over doing. Ported exhaust myself and blended bowl area of intake and unshrouded both valves myself so 0 for that. Ls6 springs and trimmed valve guides myself 70 for springs. Comp retainers and factory locks don't remember but we will say 75.00. That brings it to 895 in the heads. Now, if I were to buy a used roller cam for 100-150 for a verified good cam and put this on the stock short block it should be over 450 as it is. 0 for the headers because I already have those and they came in the vehicle this will be going in once I'm done. Was give. The carb manifold by a friend of mine who ended up with it on trade and have enough carbs to outfit a dozen engines.
This will be 383 fully forged full roller when done but with the parts I have now it should be able to make a realistic 450+/- hp and have manners. Point is there's 450hp for under 1k......barely. I know my situation is my own and everyone won't have or find the parts I have or have found for the prices I've found them nor can/will everyone do their own port work no matter how mild it may be. All I'm shooting for myself when this is done is 500hp NA and 650-700 on the bottle and still look as dogish as possible. A sleeper of sorts. I'm hoping I can hit the mark for less than 3500-4k
so you have 850 ish in heads .. and BECAUSE you already have parts to make a 383, your post sounds like a car craft or hot rod story, we had these parts under a bench wink wink
the maching work on the short block free,, the new rings and bearing, gaskets ?? what are those 383 parts worth, is that cam you plan on getting used a small base circle cam to clear the 383??
someone gave you a 300.oo intake Gave you..
do you see how much this sounds like B/S..
Ya, I can say I built a 489 for 90.oo because I already have the parts???
come on..
your 450hp will be a few thousand using normal I had to buy and pay for the parts..
not counting the cost of parts because you already have them doesn't fly..

guess that 60 over bore is free also to get to 383 from that 350.. or are you going to wiggle your nose..
 
#53 · (Edited)
Wow this thread has been going off since I last checked! I tried to read most of it and everyone has a valad point or 3 in each of everyone's posts. I spent quite a bit of money for my power! Haven't dyno it yet but I was aming for the 450hp mark and what I have done to my motor I should get that. It feels almost twice as powerful as it use to be, and it dyno at 254 at the treads a few years before the rebuild. I bought every part of my engine new except the 351 rods and 4mab crank and also had it all machined and balanced!

In the end including carby as well as MSD And new exhaust it would be an easy 9 grands worth but its all bullet proof parts. I didn't cheap out on anything. So I should be safe to sit here and clam 450hp @ (Flywheel) I built my car for a purpose and its a street racing car! I have built a very quick sprint road rally street car. Something I drive to the sprints, Race hard, and drive 5 hours back home!

Bolt ons dummy fitted!



My rockers are awesome too!

 
#72 ·
Wow this thread has been going off since I last checked! I tried to read most of it and everyone has a valad point or 3 in each of everyone's posts. I spent quite a bit of money for my power! Haven't dyno it yet but I was aming for the 450hp mark and what I have done to my motor I should get that. I bought every part of my engine new except the 351 rods and 4mab crank and also had it all machined and balanced! it would be an easy 9 grands worth
. I built my 351W for about $1,000 or so... makes about 425 HP... I could have went 450+ HP for the same money, just adding domed pistons instead of flat and a bigger cam, but that wouldn't have fit my purposes... painted whole engine black so looks stock at first glance... I use $69 valves like these instead of $500 valves... actually, they tossed in the S.S. 2.02/1.60 valves with the heads for no additional cost...

http://www.competitionproducts.com/Stainless-Steel-Performance-Valves-Valve-Sets/products/34

.
 
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