hey guys hopefully someone can help me out,im needing some advice on the top end of my build, as i said im wanting to run 450 to 500 streetable horsepower. i was thinking afr 195's with a moderate cam(im not very good with cam specs yet) and either a hsr or a miniram...is this achievable?

 

With a power adder.

We need to define some terms here. Horsepower can be rated as gross flywheel (as on an engine dyno, no accessories powered by the engine, open headers, velocity stack on the air inlet, etc.); net flywheel (on engine dyno but engine operating as it would in the engine compartment - powering water pump, alternator, fuel pump, exhaust and air intake as it would be in the car); or what you stated, rear wheel horsepower, on a chassis dyno through the transmission and rear end.

450-500 rwhp is not going to happen with 195 heads NA. If you want 450-500 streetable rwhp with a 383, you're going to have to go power adder.

Now, NA 450 streetable GFWHP, that's more realistic, but you're probably going to need bigger heads.

Next you're going to need to define "streetable". . .

 

well ive been told i dont need a power adder and to just step up the heads, when i say streetable i mean a spread out powerband all through the rpm band...not just high end for its gonna be a dd,anywhere in the range from 440 to 5 at the wheels and i would be happy

 

Whoever told you that is probably confusing rear wheel for flywheel horsepower.

 

no it was at the wheels

 

A fellow racer has a NA 500 GFWHP 383 in his '57 Nomad. It is "streetable", but he has a bunch of stall in the converter, 4.88 gears, only drives it on the street when he's done something he wants to make sure works before he takes it to the track (oil change, fuel filter replacement, that sort of thing). Carb'd, admittedly, but EFI isn't going to change things significantly.

A streetable NA 450 RWHP 454 is a reasonable goal. Power is made by combining displacement and RPMs. The less displacement you have, the more RPMs you need to achieve a give HP.

Broad torque band is another "needs definition" term. Miniram is a good way to get the most, but you're still going to need RPMs to make anything more than 1 HP/CID, and add 25% to the FWHP if you want it to be a certain number of RWHP.

I suspect you've been talking to someone who reads more magazines than turns wrenches.

 

Hi,

I've got a pretty stout 383 and plan on going to Nitrous
pretty soon. For a 383 to go 500RWHP would not be very streetable. (Radical). Without a power adder.

Mine Dynoed at 502/505 Hp&Torque at the flywheel; and
figure going to need at least a 100 shot to get to that
level.
My 2 cents

later

jaykar

 

Blk:

What's the most PROVEN HP car you've ever driven?

Why do you want that much HP out of that little bitty motor? That is, why just a little small block, and not a larger motor?

To get 500 RWHP, you need around 625 FWHP.

HP = torque x RPM / 5252.11

A 383 will produce peak torque of around 500 ft-lbs, assuming very high compression. Let's use 500 ft-lbs for the sake of argument.

That means, you need 500 ft-lbs at approx 6565 RPM, to get your 625 HP. Not that that's impossible; just, it's a mighty tall order for anything anybody would call "streetable". You're not likely to make that with a "moderate" cam, specifically it won't be any kind of a hydraulic.

You need to either rethink your goal, or rethink your cubic inches.

 

ok well then ive received faulty info...so then how about we try for 400 at the wheels is this doable?

 

Sure,how much $$$ you got?For enough of it,you can make 400hp or more at the wheels,but what everyone is asking,is why you so stuck on a 383?

Lord,this is scary,Sofa and I actually agree on something!!!

 

cuz its great power for the displacement but i dont have to go through the trouble of tryin to fit a big block under my hood, i have money and im not afraid to spend it...400 NA at the wheels would be fine for me...id put a 100+ shot on it when im at the track to spice it up a lil...what would u suggest

 

I'm sure glad everyone else spoke up before I did. I just had seeing people wanting a small CID with 500+ "streetable" NA HP. For most people, 350-400 hp is more obtainable and enjoyable. As mentioned above, stop reading all the magazine articles and talk to real world owners. Once you get above 400 NA HP with a small engine, streetable is a loose term. Something that you can hop into and drive to the store or make a 3 hour trip in without having to open the hood becomes less and less of an option. Lots of engines can do it with power adders very easily but for an engine to do it NA takes a lot more work. Just don;t believe everything you read in magazines.

Since most engines can get 1 HP per CID fairly easily, it's a lot easier to get those kinds of numbers with a bigger engine. It's also easier to maintain those numbers with a bigger engine. Don't mistake a 500+ hp SBC race engine as a street engine. Normally to get those kinds of numbers, the engine needs more than what a street engine can supply. The novelty of having to buy 112 octane fuel for your street car wears off quickly.

 

Yeah I finally just got done swapping and fired the 383 up today.
Yeah I was stoked, everytime you finish a project like this you have to be.

To be honest, with AFR200 head I would be happy with 430ish. This also has the HSR and will be going through LOTS of tuning.
The big thing I will enjoy is the monsterous trq this thing will do.

 

HI,

Other little things like camming are going to come into the picture to get there.

Although mine is streetable, with my cam selection for my combo going to have to change valve springs every so often
and run an additional vacumm cannister.

Little things to think about on your goal.

Later

jaykar

 

I forgot to add, they also want to get 20+ MPG

 

Hi,

I know if gas prices keep going up mine might end up
being a trailer queen.

Cheaper to tow than drive.

Later

jaykar

 

450-500 rwhp?? haha, my bigblock dont do that. now have you ever drove a 500hp car?? at the ground. NOT streetable. It is to an extent but you might get 4-5 miles per gallon, cuz its gonna take alot of gear to make upfor the hp l loss from the tranny, and weight of car. a 300 rwhp car is a lot of power! now there are some setups where you dont loose much power from the fly wheel to the wheels, but im only pushing about 330 at the wheels through a 427 BB. I'd say with what your describing, depending on gear and tranny in that 383, you'll make about 350hp to the ground. shoot i know a man who has a 71 charger with a 500+" blown hemi, he has a bds FI blower setup, not sure which, but he's putting 580 to the ground.... trust me you'll be amazed with the power of 350 to the ground!

 

my 383 put down 550hp 490 ftlbs at the crank on pump gas, thats approx 430-440rwhp range. You will not do it with a moderate cam or the 195s. I have a set of tricked out afr210cc heads and a solid roller cam. Runs great on the street but it'll cost u a pretty penny at the same time. BTW my motor is for sale, PM me if ur interested..

Mike

 

If youll check out Air Flow Research and go to the articles link there is a 540 horse 383 with the 195cc heads that car craft built. Read up on there project. They also claim they could have made more horsepower with the motor by changing some things up. So i dont see why it couldnt be possible. Anyways good luck

 

That's still far from 500 RWHP.

 

How streetable would a 454 small block be with 500 rwhp.

 

Not very

 

Just get yourself a heads and cam ls1, 450 is reachable with the right parts. Sorry just had to put that in there, i know the ls1 isn't feasable for most.

Anyways 450 fwhp is definaly easily reachable for a 383, but too the wheels would be tough to do if you still want to DD it.

Justin

 

Cool thats my next build. As for the LS1 I could do that but then I would have to buy a new set of AFR heads and the ones I got now took to long to get here.

 

Haha the time to get your afr's would be the least of my worrys if you were going to do the swap.

 

Now if your talking 454 SB:

Yes you could build one and it would streetable with the
rite parts combo and run pump gas
But now your looking at alot of money starting with the
cost of the block

Taking a guess, I'd say 15 grand in the motor and you do the labor. And your going to have to run some pretty big
heads to make it there.
Then there's the exhaust problem, Minimum 1 7/8 and
true duels as a guess.

My 2 cents

Later
Irocing

 

I think you could do it with a 400 block, with a nice set of heads and a decently sized cam.

Justin

 

Your talking 625+ FWHP, (Streetable) out of a 400 on
pump gas.
Not saying it can't be done, Never say Never, but with
that block not practible.
Going to have bring the compression to the edge, Cam
it big and take a good set of heads and do some work
on them. Then your going to have to do some fancy
exhaust work to get there

Have built a few 400s in the past so I know the block
very well. Most of them I destroked to 372 and made
big HP, at 7800 with all the good stuff for circle track
racing. The block is not very strong. Built a couple 406s
for the street using the 2 bolt upgraded to 4 bolt. Lost
the bottom out of one and blew across the top of Cyl wall
on a couple others. These were studded top and bottom
with O-Rings and copper head gaskets.

Streetable to me is to be able jump in the car, start it up,
not have to play with the throttle for two minutes to keep
it running, drive down to the store in traffic for a six pac
of sodas,rite! and stop for some gas at the corner service
station.
625+FWHP-Pump gas-(All motor)-Streetable 350-400c.i.
Show me.

Later

Irocing

 

I think you could do 450 rwhp out of a 400, my ls1 makes 430 and will defintaly make 450 once i get an intake, and i can jump into that and drive it everyday no problem.

But i've never built a 400 so i can't give you a correct answere, i'm just going off what i have done with my 346 LS1, and figured i could get more out of a 400 block carbed set up.

Justin

Oh and since when does 450ish rwhp make 625 fwhp, 500 rwhp would only be about 575-600 fwhp.

 

All this is mute anyway I assume he already has
the 383 shortblocked and wanting AFR 195s and moderate
camming to get there.
Bottom line is there's no replacement for displacement
when going for the big numbers, unless your talking about
spinning them ala F1-Indy-Cart motors.(Not streetable).
Everyone talks about HP, when for the street what I like
to set up my motors for is Torque in the range my gearing
is at.

Outa here

Irocing

 

I agree, when I built my motor i was going for the most power i could under the curve. I wouldnt want to rev to 8k on the street, but i was just trying to say that it could be done. I still make 350 rwtq at 3000 rpms, and peak at 396 at 4800 so thats derfintaly a usuable band for the street.

I was just trying to say that I think it could defintaly be done. Theres a lot more to it then just throwing in a large cam, valve events, dynamic compression are big factors in maximizing power under the curve.

Justin

 

Straight from a John Lingenfelter book about modifying small block chevy engines:

Emissions LEGAL 383 LT1:
425HP @ 5500rpm / 468TQ @ 4000rpm

T-56 6 Speed Transmission
SuperRam Intake
Lunati 1-piece seal, steel 3.75-inch stroker crankshaft
JE forged pistons
4340 steel Oliver rods
Hydraulic roller cam 219/219 @ .050, .503/525-inch lift, 112* lobe-separation
LT1 Heads CNC-ported with 2.00/1.56-inch stainless steel valves

This combo, in a Firebird tested by Motor Trend, ran a 13.10 @ 113mph and tested 410 RWHP on a chassis dyno. At another track w/better traction and a set of small slicks the car ran a 12.10 @ 116mph. All through complete exhaust including cats.

I don't know anything about cams (PLEASE explain what the numbers mean in terms of being "streetable"!) But if that cam is "streetable" then that sounds like a winning combo right there for you... and ME! Nearly 475lbs-ft of torque at 4000rpm on the dyno and 410 RWHP to the ground.

Any good estimates on how much this engine would cost to build? I've just bought an '89 vert for a DD and I'm turning my '92 t-top RS into a project and I want it to be as beastly as possible without breaking my piggy bank. Probably the most vague description possible of what I want to do but but I can't see justifying the cost of an LS1 and its more expensive parts if I can go LT1 and make out almost as good?

 

That motor is a good example of a good torque motor
for the street. I would have put a little more duration
and lift in there, even with the reworked LT heads and
smaller valves.
Could have probably picked up more torque to 5500
with TPI Large tubed runners instead of the ram.

As to cost would depend on what you are starting with
and the strenght of the bottom end.

Later

Irocing