Dyno Guess on the 383

[Coyote with a roadrunner]

Ok gang I recently posted pics of our 383 redone. It has the following specs and I am wondering if any of you care to take a guess as to the HP once we test it. I honestly have no clue as this is our first try at this. I will give kudos to whomever is right. Thanks for playing!

It has:Comp cam, extreme energy, 268 duration, little over .5 lift, 906 heads, decked, stainless valves and new hardened seats, flat top speed pro forged piston, 1.6 ratio hughes roller rockers, 7 quart deep oil pan with windage tray, preformer RPM intake, and 800 CFM Eldebrock AVS MSD pro billet, plus 6A box, Heddman headers, Expected HP, we hope to to be in the 400 to 450 range, 450 to 500 torq, we hope.
This is not our shop, wish it was. We will let you know how the dyno goes.

 

[generaljmwlee]

let me be the first 428horse

 

[moparstuart]

385

 

[MarPar]

408hp / 436 tq :HappyNewYear:

 

[Jeff_383]

415 hp/445 tq

 

[wannadrag]

375 hp

 

[1fast72]

415 hp w/ 435 tq

 

[74sundance]

A stock 383 will bang out at 335.2 hp at 5,000 rpm, and 392 lb-ft at 3,600 rpm

Dyno tune it and you can get 338 hp at 5,000 rpm and 394.6 lb-ft at 3,600 rpm

Slap on a set of headders and an intake 367.2 at 5,100 rpm, and 434 lb-ft at 3,600 rpm.

Add a cam and a proper tune and you can reach 406 hp at 5,400 rpm, and 433 lb-ft at 4,000 rpm with stock heads so 406hp and 433lb is my guess

 

[iraqivet01]

391 Hp
404 torq

 

[68ChargerAG]

435 hp

 

[Gary_gtx67]

your carb is way to much for your combo!! Im running a 383 bored .30 10-2-1 keith black hyper utetic flat tops with a comp 280 cam, heads have been milled .40 for compression and with oversizes valves , edelbrock rpm performer intake and a 750 cfm holley. dynoed at 485 hp and 508 ft lbs of tourqe! Thats with a 2800 stall 727 tranny and 3.91 posi.

 

[Meep-Meep]

Hmmm, wild guess based on what you wrote plus a few assumptions. 390 HP / 435 ft-lbs.

 

[74sundance]

your carb is way to much for your combo!! Im running a 383 bored .30 10-2-1 keith black hyper utetic flat tops with a comp 280 cam, heads have been milled .40 for compression and with oversizes valves , edelbrock rpm performer intake and a 750 cfm holley. dynoed at 485 hp and 508 ft lbs of tourqe! Thats with a 2800 stall 727 tranny and 3.91 posi.

Very true.........
Engine Displacement -VS- CFM:

289 - 302 Stock 500 CFM Mild 600/750 CFM Race 750/UP CFM
351 - 400 Stock 600 CFM Mild 650/750 CFM Race 800/UP CFM
400 - 460 Stock 650 CFM Mild 750/850 CFM Race 900/UP CFM
460 - UP Stock 750 CFM Mild 750/900 CFM Race 1000/UP CFM

Or 1.5 x 383 = 574 so you could round up to a 600cfm carb. Unless your building a monster motor a bigger carb is a bad idea!!

 

[Mopar]

with the adjustable valve secondary, can't it be toned down a bit instead of downsizing?

 

[Gary_gtx67]

If I'm right that will not do any thing. The cfm has to do with the metering blocks and how big the main body is designed along with the butterfly size and so fourth.... Would anyone like to back me up on that or am wrong on this?

 

[Mopar]

i'm just simply asking, because i'm curious myself

 

[69 Runner]

Theoretically you can indeed limit the fuel flow by delaying the secondaries until there is enough RPM to handle the gas.

HOWEVER.....

until that point you'll just be running off the primaries. So even though you'll get a real "kick in the pants" when the secondaries open up (ever run a Thermoquad?) you might run slower. A smaller carb could pull the secondaries sooner, using more fuel than the larger carb waiting on the secondaries.

 

[Gary_gtx67]

True mr 69 roadrunner!! Good input. But delaying the secondary wouldn't be worth it if the cam he is running doesn't have a high rpm power output. For example some cams are a 1200 to 5600 rpm by the time you delay you would have already reached your shift point due to the lack of cam. Correct? Or am I thinking to deep into this?? My brain is tired!

 

[Coyote with a roadrunner]

Well it seems that we oops'd on the carb. I would like to ask for your opinions on a correct carb, so that we get it right. Thank you for the feedback.

 

[69 Runner]

True mr 69 roadrunner!! Good input. But delaying the secondary wouldn't be worth it if the cam he is running doesn't have a high rpm power output. For example some cams are a 1200 to 5600 rpm by the time you delay you would have already reached your shift point due to the lack of cam. Correct? Or am I thinking to deep into this?? My brain is tired!

Nope. You've got that bull by the horns. I ran a supertuned 625 AVS on my 69 Bee (#'s 383 auto) and had the secondaries delayed. I was running the original converter and only 3.91 gears. So they didn't open till over 4000, but that motor made power till 7000.

So it got moving, then it got crazy.