i am getting ready to build a second 383 for my 75 and i am looking for a target of 500 or more hp. i have a great block with billit splayed caps, has been decked and align honed. i am looking at getting a forged eagle crank and 6" h-beam rods. i will also be using forged pistons and a hyd. roller cam. i would like to keep compression in the 10.5 to 1 area to stay pump gas friendly as this will be a street and track toy but not a d/d. i am looking for a very lumpy rough idle. my trans is a built th400 with a 2800 stall and i will be going with 3.90 gears in the rear. what cam and head combo would give me this kind of power with this set up? also what kind of intake should i use, a dual plane or a single plane? what manufacture? i am not just looking for peak power, i also want lots of throttle response and power everywhere under the curve. i am very interested in knowing a good target for cam specs and finding a set of heads that will be up to the task. thanks for any help you guys can give me.
500+ hp 383 needs higher rpm ability to attain it. So forget using a H-roller and its rpm limitations.
I use Dart 227 CC heads with 2.08/1.625 valves
11.2 compression
Motown single plane
headers and dual three inch exhaust
Solid roller 236/242 with 1.65 rockers
7500 rpm red line and it's still pulling hard.
My opinion would be to put your money into a set of smaller, good flowing heads. I think the best bang for the buck right now is the AFR 195cc Eliminator heads. According to AFR, they flow in the 280's at .55" lift. You can also check out an American Speed built 383 with these heads at http://www.airflowresearch.com/eliminator.php Keep in mind there is a lot of AFR hype in their advertising, but American Speed are pretty straight-shooting guys and they do dyno everything they build. (I'm also not sure if American Speed's dyno uses SAE corrected numbers for temp and humidity. Since they don't list it, I'm guessing it's not.)
I'm with gkull on the solid roller, if it isn't a daily driver, go with a solid street roller. I have countless simulations of a 377 sbc (4.125 bore x 3.5" stroke) on Engine Analyzer. Throw on a street roller at 240ish duration and .6" lift, a set of AFR competition ported 195's, a Victor Junior, and 500HP seems easy. Again, take this with a grain of salt as it is only a simulation.
with the modern cam designs you could achieve this with a big hyd cam or a nice solid.rollers are great but they do up the expense.
i would think a 24x*ish @.050 would get you there.being a sbc you have more heads to choose from than anyone.afr,eddie rpm,brodix,summit,etc.choose one with an intake runner around 200 cc and you should be fine.i would think a port matched rpm intake would work well,especially on the street.that is a heavy car.
so far i have changed up my plans to a 396 via a 3.875 stroke. i am looking at a set of brodix ik200 heads or the afr 195's with a comp cams adv dur of 293-299 and .540 int and .562 exh. i am also looking at the rpm air gap or the brodix dual plane. this set up should be very good at doing what i want it to do. any opinions of this strok set up? how many of you have tried it and how did you like it? the a/c and components are going bye-bye as it has never worked very well to begine with, along with the fact that i removed the a/c duct work to hide the msd box under the dash. the front bumper went on a diet and lost quite a few pounds also. this should help a little with the weight as well as going to aluminum heads.
Last edited by 2000FRCZ19; 12-26-2006 at 05:50 PM.
If your going to spin it above 6000 rpm go with a single plane intake. I ran a 350 with a large solid flat tappet with both a dual then single plane. I lost nothing at the lower end but gained a lot of top end. I know run a single plane on my 385 motor with a large solid flat tappet that sees 7000 rpm and I would not think of using a dual plane. You will not lose much down low.
The combination you're looking to do is fairly straight-forward. You could actually get there with the cam GKull has listed. Along with 10.5 C.R. and almost any aftermarket aluminum cylinder head. The dyno tests we've been doing on these units peak at about 6100, which is no problem at all for a retro hyd-roller.
We actually use those cam specs (234/242 x .540/.560 x 107 ICL) on many of the builds today. The unit in the photo below was originally tested with 780 Holley and made 480 HP. The customer then changed the single carb to an Edelbrock 2 x 4's and now has over the 500 HP number. He has an o'drive trans and the car is very comfortable during normal driving.
With respect to the intake manifold, stay away from the "divided" plenum. The idea behind this type "divided" intake is to help increase the torque numbers by raising the air speed. You don't really need that on these strokers. You simply need enough air getting inside. The stroke/C.R. will deliver the torque, an open-plenum will let the correct amount of air in! Hope this helps some. Thanks, Gary in N.Y.
By the way, the heads here are from Brodix in 1988 with 2.020's, 1.600's, and 184 runners, and with straight spark plugs to boot! We used a set of Crane offset intake rockers and std. exhaust's with adjustable guide plates. Plenty of pushrod clearance and absolutely no header issues. Also runs fine on 91 octane.
P.S. Just my own opinion here, but when you get into the 11:1 C.R. area, you need to get up to 250* @ .050 minimum. Especially on strokers, they tend to "tame" down cams somewhat! I was surprised how low the 2 x 4's sit under the hood. Customer claims simple tuning also with multiple carbs. Personally, I never cared much for that setup, would have chosen a tri-power first.
P.S. Just my own opinion here, but when you get into the 11:1 C.R. area, you need to get up to 250* @ .050 minimum. Especially on strokers, they tend to "tame" down cams somewhat!
Gary my original build used a Crane 232/240 112 with 1.6's even with Swain Tech thermal coated piston, chambers, exhaust valves was very ping prone on our California 91 super unleaded. 18 inititial 14 mech all in at 3200 rpm. I then jumped up on the cam to 240/248. 112 the ping was a thing of the past, but the motor was just too high strung with a 700R4/4.11 rear. It would have worked in a 5 speed closed ratio. I now dropped to the above cam with 1.65 to get the lift to .620/.620 net lift. I've never had ping problems even out lapping in 100 degree weather with water temps up around 230 F
Valve Timing At 0.006
Open Close
Intake 41 73
Exhaust 84 36
These Specs Are For The Cam Installed At 106 Intake CL
Intake Exhaust
Duration At 0.05 242 248
Lobe Lift 0.36 0.375
Lobe Separation 110
i plan on staying in the 10.2 to 10.5 to 1 comp ratio to keep away from detonation. i would like to try to go with a hyd roller cam to stay street friendly but if the up keep isnt that bad on the solid rollers i might go that way. thanks for the advice so far.
That cam would be pretty hot for a 396. I had that cam in my 427 only I used solid roller on it. I only had about 10.4 compression. So the DCR was lower than I would have liked. It really needed low 11:1. I was using 7000 rpm as my red line
Check out this link. Joe Sherman has started fooling with the new eliminator AFR 195's and he weighs in on his first 383 build with them. The cam sounds a little aggressive for the street but he's getting well over 600HP on out-of-the-box heads:
Check out this link. Joe Sherman has started fooling with the new eliminator AFR 195's and he weighs in on his first 383 build with them. The cam sounds a little aggressive for the street but he's getting well over 600HP on out-of-the-box heads:
I read this whole thread. There is nothing new, that is why he said he used 210-220+ cc on serious 383's. Engine dyno guys have said for years that it takes @300 cfm of intake and @210+ cfm exhaust ports to achieve 600 some hp.
The new AFR 195's achieve these flow numbers where it used to only be the bigger cfm heads.
Like you said, I have built a couple hundred 383 engines that were somewhat like this test buildup. I feel these new AFR heads were worth 25 to 30 HP over some others I have seen, I usually use the 210 or 220 size on the more serious 383 engine builds.The cam I used was NOT a street type grind, so I am sure it had a lot to do with the big HP numbers. For example, the best HP output from any 383 I have tested that was even similiar was 628 HP, with a bigger cam and 12.75 to one compression and an other brand of cylinder heads. JOE SHERMAN RACING
gkull, you are getting jaded from your years of racing and building motors.
I agree it's not like turning water into wine, but the AFR Eliminator 195's make it possible for an average joe to build a streetable 550HP 383 with a $1400 head. (A really good head porter would say he could have done this years ago in a 195cc head, but his bill would have approached $3K.)
Something to be said for bringing technology to the masses.
I would agree that the 195 Eliminator heads are the way to go on Street/Strip 383's. Most of the time Street/Strip means Street but they can make enough power do to some damage in drag. I have seen about 50 sets sold for use on 383's to 421's. Even some 350's but its not my first suggestion. The Comp Packages are even better if your willing to shell out 2k for the set. AFR should have them by the end of January allong with the new Eliminator 210cc heads.
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383 cam/heads help
