I just was wondering if anyone out there has any proven combinations out there, naturally aspirated. I have just built a fresh 383 that made 517 at the flywheel on our stuksa water brake dyno, and was wondering, are there are any other combinations out there that have been dynoed? I would like to hear your imput.

thank you,

I would like to hear details on your combo that got you 517 hp.

350 four bolt, bored .060, decked, line honed
SRP -5.4cc flat tops .008" in the hole
Eagle cast 3.75" crank, balanced
Eagle SIR 5.7" rods floating pins
Stock 8" balancer, HD flexplate.
Trick Flow 23* heads, 195cc int 64cc chambers, mild port work and 2.055/1.60 valves
Victor Reinz Ultraseal head gasket .028" comp thickness
Victor Jr intake with 1" open spacer, port matched to heads
Comp Cams 294s solid FT with 1.6 roller rockers
MSD ignition with 6AL box
TH350 trans, Coan 3000-3500 street converter
3.55 gear, Auburn posi
Hoosier Quick Time Pros

Based on vehicle weight and MPH makes 513 HP at the flywheel.

Mine might make upper 4xx's. READ: It doesn't matter what the dyno says, it's what the time slip says that's important.

Best so far is: 7.15 @ 96 with 1.54 60'

I've yet to test my newly installed RPM AirGap but I'd expect .02-.03 reduction in 60'.

383
10:1
AFR 195's
HP 750
RPM AirGap (was Victor Jr.)
244/252 @ .050 .577/.600 on 108 LSA roller
1-3/4" headers with 4-2-1 Scavenger Collectors
3" exhuast with 3" X-pipe

TH-350
8" ATI Treemaster 4500 flash
12-bolt with 4.56's
28x9 ET Drags
Cal-Trac type bars
3300 lb with driver

Shifts at 6500

;)

mine made 525hp @ 6200 and 495tq @ 4950. i have not had it on the track yet but im not very optomistic. As garret pointed out a dyno is not the 1320. my goal is to run 11.50s but i dont think its going to happen. i have no low and mid range tq and hp i cant even get too because of the hydroroller. a solid roller would better suit the engine but i just refuse to run one on the street. i can either replace my heads and intake or go to a 406 to fix the problem. pick your parts wisely. Dave http://www.cardomain.com/id/sheetmetal

I will agree that the dyno isn't the track, but an Impala isn't a Camaro either. The 383 I have built has a cast crank, Brodix track 1s, paper rolled runners and combustion chambers, 11.0:1 compression, solid roller cam 280/288 .587/.587 (with comp stainless roller rockers), comp endure x roller lifters. 750 Holley DP, victor jr, port matched and paper rolled. :This engine was just fired, allowed about an hour to warm up, and pulled 3 different times with a current best of 517/495. graemlins/beers.gif

Whoops! 236/244 on duration for my Camshaft, not 280/288 (advertised)

Im thinking you should do very well with that set up. the smaller soild roller should really help your engine. do you happen to know what the open and closed spring pressures are? also what cam did you go with? and what size headers did you dyno it with. my car is a 3400# chevelle. Dave

Well, hopefully I am right in there with you guys.

4 bolt 350, .060 over
scat 3.75" crank and rods
wiseco forged flat tops -5.4cc's
hasting moly rings
pro-topline 200cc iron heads 2.02/1.60, no port work other than knocking down the casting boogers
comp 294s solid flat tappet
1.6 magnum roller tip rockers
weiand 7530 team g
750 edelbrock (for now)
1 3/4" headman headers
moroso oil pan w/windage tray and crank scraper
ATI 10" streetmaster (should be 3400-3500 flash stall)
3.73 gears and eaton posi

My '77 nova is a bit heavier than a 1st gen camaro, but it should still do ok.

I built a 383 and dynoed it, this is for a daily driver.
Almost smooth idle and pulls around 18" vac.

350 w/ a 383 Scat kit.
10.8:1
Race Demon 1000
1" spacer
RPM intake
TFS 215R heads, 2.05/1.60s - ported by your truly - 301/236 cfm.
Comp 224/224 hyd. roller 568/568 on a 114LS installed straight up.

It made 490hp@5900 / 495tq@4500
with 1 3/4" dyno headers.

SHEETMETAL
I dont wanna hear that from you, if your car doesnt run low 11s (high 10s eventually)
I'll personally stick the other 2 plug wires on for you! :D Remember Johns 355 was running
11.70s in his Chevelle, theres no reason why a 525hp 383 cant run WAY better then that.
By the way I went for a ride in Johns car 2 weeks ago - with the new 603HP 422SB the
thing would just blow the ET streets off in 2nd gear at 40mph - just go sideways.
It was fun, but he's gonna have a hard time with hookin it.

seat pressure 240 at 1.910 and 540 open Were my spring pressures.

seat pressure 240 at 1.910 and 540 open Were my spring pressures. Headers were 1 3/4 and the camshaft was a custom grind from Comp cams that was laying around the shop.

WOW 67RS502!! With those cam specs I would have pegged the output at about 450HP. Do you think the ported heads made the difference?

Well I think the porting had something to do with it.
I tried not to take out a bunch of metal, the heads should be around 220-225cc.
Also the chambers were "fully done" - I unshroud the valves to the bore,
laid the wall back to the plug (long side), blend in the valve job.
Chamber work makes a big diff. in power - that most people dont realize!
And I may actually do some more work on the intake ports. graemlins/clonk.gif
I think with a Victor jr it could make 500+hp.
But the RPM isnt ported yet - this should give it a few extra horses.
(but it couldnt be a stock lookin, painted all black SB with a Victor on it, and it can
with a RPM)
I've already got plans for a "almost smooth idle" 406 daily driver motor which will make
more power with the same stock look. Somebody's gotta beat up on those new Cobra
mustangs with a stock lookin SB and ask - "what? EFI, 4 valves per cylinder, a blower,
cost how much, and cant beat my work truck?" - that a ford for ya. tongue.gif

67RS502- thanks for the vote of confendence. im glad someone believes in the engine. my concerne is the shift recovery. theres really no need to spin the engine over 6300 (valve float is at 6450) and the shift will drop me well below decient torque. with a heavy rotating assembly i believe the engine will lose some time building back up into decient power and rpm. im thinking its going to be more of a low 12 second car as it sits. John invited me to come ride in his car also. i need to get over there and take a look at some other things as well. Later Dave

As for head flow - let me put it this way:
Let compare a AFR 195 and the ported TFS215R heads.
My engine would make around 425-450hp if I had used say the AFR 195 heads.
Since everyone likes the AFR's so much, (I'm not too fond of them), I thought they would
be a good comparison.
The AFR 195s flow around 262/198cfm - with a smaller runner then my heads.
MY TFS heads flow 301/236cfm - with a bigger runner, but even though the runner is bigger,
my heads flow 39cfm more - so the air speed (velocity) is higher with my TFS.
Now the formula for figuring out the HP from CFM is:

CFM x 1.8 = HP

So we take the 39cfm x 1.8 = 70hp, meaning that my TFS heads could make around 70hp
more then the AFRs. Now this is just a theoretical formula that cylinder head manufacturers
use, and flow #s arnt everything - so its still a guessing game, but it can guesstimate the HP
advantage 1 head can have over another from the flow. (as long as other things like chambers
and heads, valve angles are of the same basic design) To me the formula like most is a bit off.
(I like to use a factor of 1.5 - and that would be a more realistic 58hp diff.)

Anyway now you see how a good cylinder head can make hp, 40+/- cfm will = big power gain
Heads will make or brake a motor, chambers/valve jobs alone can make a 20+hp gain.

SHEETMETAL
I think you have a 8" ATI, I've had one in my car, and now have a 10" ATI.
With that loose a converter you'll keep the rpms above 5000 easy!!!
When I shift @6500 the rpm drops to around 5300 and thats with a 10"ATI 2500 stall.
So when you shift your 8" will keep you way above peak TQ rpm - nothing to worry about.
Also remember my buddy Mike (when we saw you at Owens) his all steel 70 Chevelle
with a Owens built & dynoed 406 - 440hp 500tq, has run 12.0s@111, with a "2000 stall"
and 373 gears! Your car will be lighter and your makin 85 hp (same dyno) more, have a looser
stall and more gear - now what does that tell you??? graemlins/clonk.gif sound like easy low 11s to me.
Be sure to let me know when you headin out to the track!
I could see your ride going 12s, yes - on a 1/8 mile pass, when youre coasting
:D

Haven't had my underachiever 383 SBC on the engine dyno, but have had it on the chassis dyno and down the track quite a bit. Best of 389 RWHP. The chassis dyno was with an 8" ATI - MRT converter(~4200), 4.56 gears, and ET Streets. A/F ratio was pig rich at about 11:1.

Before the latest round of upgrades it made 365 RWHP and went 7.37@93.23 in the 1/8th. I feel pretty good it would go into the 7.20's(already went 7.39 with the 60' off by .08 due to poor track prep.) even in the heat and likely in the 7 teens in some nice cool weather and a little more tuning. Car weighs 3600 lbs. with me in it. I'll never know for sure though as the engine sitting on a stand to be disassembled and sold(hopefully)

Details on the car/engine can be found at

http://members.aol.com/jgchevelle/racing.html

Dave,

I have to agree with 67RS502. I think you are in for quite a surprise. It may take you a little time to tweak it, but you're making enough power to go low 11's and maybe better. You'll see the light when you drive it in the coming weeks smile.gif

Greg Nuibe went 11.39 @ 3400 lb with a mild 383 running Edelbrock heads and a small solid bumpstick.

Originally posted by 67RS502:
As for head flow - let me put it this way:
Let compare a AFR 195 and the ported TFS215R heads.
My engine would make around 425-450hp if I had used say the AFR 195 heads.
Since everyone likes the AFR's so much, (I'm not too fond of them), I thought they would
be a good comparison.
The AFR 195s flow around 262/198cfm - with a smaller runner then my heads.
MY TFS heads flow 301/236cfm - with a bigger runner, but even though the runner is bigger,
my heads flow 39cfm more - so the air speed (velocity) is higher with my TFS.
:D You are comparing apples to oranges here. It is obvious that 195s are too small for your 502. We are talking a 383 here. Why wouldn't you compare similar size AFRs? Have you tried them? Similarly worked AFRs will compare very favorably to your Trick Flows. The rest of your post is meaningless because 195s would be a mismatch for your combo.

he wasn't talking about his 502, if you read all the posts he was talking about a 383 that he has.300 CFM is a pretty big number! I have talked with you before and you definetly know your stuff but AFR's best head 227cc racing head barely flows 300 and their raised runner head only flows 320 at .600 lift. What lift numbers do your heads flow this at? also what do you think your CC is about 225CC? that is a big port; 30CC's bigger than the AFR 195's so i don't think that is a fair comparison and i don't think it would have that much more velocity considering how much bigger the port is. However if your heads do flow 300CFM congratulations!!! that is very impressive, and I am sure much cheaper than buying a set of the CNC'd AFR's!!! smile.gif

Yea the TFS215R heads are for my 383 SB.
You are right Cody, they flow 301@700 and 295@600. Thats why I hate to use
the 1.8 factor, and like to use the more realistic 1.5 But the 215R exhaust port kill
most other heads across the board from low to high lift. I'm just using the 2 heads
as an example - since I'm pretty familiar with the 2 castings, could have used
any other 2 that flow similar #s. My point was that by lookin at the flow #s you
can get an idea as to what kinda power diff. you can expect between 2 heads
of a similar design. Go with a good flowing head and you can "de-cam" a motor,
and make a good mild daily driver out of it, and still make good power. Then if
you wanna make more power, and can live with a bigger cam you can throw a cam
like Sheetmetals and still have a very streetable 383, and then make big power
like 525hp - but thats thanks to a good head, like the Greg Good ported AFR
Sheetmetal is running. Another words his 383 wouldnt make 525 if it wasnt for
his heads - that where the power is! A good example is bolting on a set of 18deg.
heads over 23deg. heads - you will see a 100-125HP gain with just a head swap.

Cody, and everyone interested in the new BBC AFRs:
We just got my friends new fully cnc'd AFR 335 heads in yesterday. They're
supposed to flow around 410cfm, we will flow them this week and I'll post the #s
if anyone is interested. We're expecting around 400cfm, on the local bench that
we use. The quality was good, AFRs new BBC heads are probably the best
out-of-the-box head out there. This is for my friends 533 - it should make around 700hp
with the 335s.
graemlins/hurray.gif

We flow tested my Trac 1s, and with them being CNCd and paper rolled they went 309 on the intake and 226 on the exhaust at .600 valve lift. .550 was 302/223.

Guys, I find this subject extremely interesting as the usual path was to put "good" heads on an engine and over-cam it to get these HP numbers.
The trade rags always stress port velocity over huge CFM numbers, but it appears from this thread that a mild cam and ported "good" heads can make huge HP. I suspect streetability is important for most of us non-racers on the team.
67RS502 that 1000cfm carb seems too big. I wonder what type of HP it would make with the usual street 750cfm....

Those are excellent int # on the Track 1s by the way.
Gator:
Oh - you're not gonna get my started on carbs now are you - too late!
Yes the Race Demon 1000 is too big for the 383 (for the street anyway), but you'll be
happy to know that we dynoed it with a dyno carb they have, I think its a BG775, it made
about 5hp less with it. I didnt do any jetting on either carb. The cfm ratings are more of a
generic "name" nowa-days. A 850 speed demon is the same carb as my 1000 race demon,
(minus the choke tower) so thats not what they really flow - they're both an 850body
850baseplate carbs that flow little over 900cfm. I just got my Proform 950 body & 850 base
plate in, and will be trying to piece together a cheapy "custom carb" - I'll let you
guys know how it goes with it. I'd recommend a HP 950 Holley for a 383 - its a 750body,
850baseplate and works great on the street.
As for heads, I've been doing alot of research on 'em. And yes, if a head can flow good #s,
has a good design, a good chamber, is ported to have good swirl, it is the way to go on the
street, ever thou its a bit on the large side, as long as it has good air speed (velocity). As you
can see my 383 wasnt down on TQ, it still made the usual - around 500tq that most healthy
street 383s do. This is no where near what most people do with BBCs when they go from
oval ports to rect. ports, thats a big jump in runner size, but if your going to a good flowing
rect port head that flow say 75+cfm more then the oval port you had, then the airspeed will
increase and you'll have way more HP and more peak TQ too. Also a good example of the
larger but better flowing heads are the Fastburns - the intake runners are around 210cc, they
flow good out-of-the-box #s, but GM uses/made them for the average 350SB. (most would say
their too big)
Another example is the LS1 heads - they have large intake ports (cross section) for a 346,
but work very well, and make good power across the entire rpm band, thats why you see
these cars makin big power, with ported heads, and running 11s with mild cams and 10s
with streetable cams.

when Greg ported my AFR 195s they finished out at 210 runners and flow 300/226 at .600. they flow like 306/230 at .700 but ill never use a cam that big. they also still retain the 2.02/1.60 valves. my heads arent set up to take a cam over .600 lift as i will get into coil bind, but i fell there is proably another 25/30 hp in it with a solid roller. i may find another 10 or so hp in it with some other things i may try. but i got to get it on the road first.

Nice to know that about the Carb sizing smile.gif
You mentioned the 383 combo below:

350 w/ a 383 Scat kit.
10.8:1
Race Demon 1000
1" spacer
RPM intake
TFS 215R heads, 2.05/1.60s - ported by your truly - 301/236 cfm.
Comp 224/224 hyd. roller 568/568 on a 114LS installed straight up.

It made 490hp@5900 / 495tq@4500
with 1 3/4" dyno headers.

Were the rocker arms 1.5 or 1.6 ratio?

Yes I'm runnin 1.5,
later on if I need a 10th I could try some 1.6s

Interesting thread. There is more than one way to skin a cat - I like 67RS502's way of using awesome heads and a smaller cam. The other way is exemplified by Edelbrocks Performer RPM combo - small heads (with small runners) and a long cam. That way works too, but why?

IMO I think that a good flowing head with small runners has very high velocity through the ports. This helps overcome reversion at low engine speeds and possibly helps with scavenging at high RPMs too.

The other method (large port heads with a small cam) is kind of cool because then the limiting factor becomes the cam. The mild cam pattern helps low speed driveability by limiting cam overlap and reversion so port velocity becomes less important. At higher RPMs the engine needs less overlap time (degrees) because the heads flow so well during the shorter overlap period anyway.

Just my opinion.

PS. On the cfm / HP formula one has to remember that the HP number you get is really the HP limit for those heads. there is probably something else that will hold the engine back from reaching that number unless you have a perfectly optimized combo.