CheezMoe

Greetings folks, hoping some motor guru's jump in here. Short cliff notes:

Purchased TKO 600 kit over the winter to switch from the TH400 which I was well bored with. While we had it apart we found #2 had leakage, and others on the right side were disparate. So a full bottom end re-build was at hand. The project is complete and the car is driving and running fairly well. Still working break in procedure recommended by Diamond racing for piston/ring set we installed, and much tuning to do, especially in the carb with the new cam.

My engine specs are below. At some point we will hit the chassis dyno, but for now if anyone with a Desktop Dyno app who could run this for me It would be much appreciated. "Educated Swags" also welcome. Comparing these specs to zz383, I would like to hope to at least a little more power.


Block: Chevrolet Target - 4 bolt Main
Bore: 4.040
Stroke: 3.75
Cubic Inch: 385
Litre: 6.3
Crankshaft: SCAT 9000 Cast Steel
Rods: SCAT 4340 I-Beam
Bearings: Clevite H-Series
Pistons: Champion Racing, 11123 Flt Top -5 Billet/Forged. Total Seal Gapless Rings
Heads: RHS Pro-Action Aluminum
Int/Exh: 2.02/1.64
Chamber Size: 72cc
Runner Size: 200cc
Camshaft: Howards Hydralic Roller CL110255-12 284/288 231/235 .510/.530 112 108
Rockers: Scorpion Racing Roller 1.5
Timing Chain: Cloyes Double Roller
Intake: Edlebrock Performer RPM
Carb: Holley Ultra-DP 750cfm

Bore: 4.04
Stroke: 3.75
Displacement: 385/6.3
Combustion Chamber: 72
Deck Height: 0.020
Gasket Thickness: 0.040
Dome/Dish/Valve Relief: -5cc
Piston Ring Height: 0.19
Piston to Bore Clearance: 0.0028
Connecting Rod Length: 5.7
Cam intake duration: 284

Static Compression Ratio: 10.89:1
Dynamic Compression Ratio: 8.08:1

Any and all thoughts are appreciated.

bluedawg

I'd go forged on the crank if ya havnt already bought it. Don't no much about the rhs heads bit I'd guess 450 hp maybe 475.

gkull

It will be pleasantly mild and a nice cruising motor. I'm driving a 383 in my vette now and have put on a couple thousand miles in the last six weeks. I also have the 600 tranny.

I would guess that with 10 more degrees of cam and a point of compression that you would exceed the power output of ZZ383.

ZZ383 Engine Specifications:
Displacement: ........................................ ..... 383 cubic inches
Bore x Stroke: ........................................ ..... 4.005 inch x 3.80 inch
Compression............................. ................... 9.7:1
Block: ........................................ .................. Cast iron, four-bolt intermediate mains
Cylinder Head: ........................................ ..... Aluminum “Fast Burn”
Valve Diameter (Intake/Exhaust): ......... 2.00”/1.55”
Chamber Volume:................................. ....... 62cc
Crankshaft: ........................................ .......... 4340 Forged steel, 1 piece rear seal
Connecting Rods: ........................................ 5.7” Forged, powdered metal, 3/8” studs
Pistons: ........................................ ............... Hypereutecic, 244-T5 aluminum alloy
Rings: ........................................ .................. Plasma Moly
Camshaft: ........................................ ............ Hydraulic roller tappet
Lift: ........................................ ................ .509” intake, .528” exhaust
Duration:............................... ................. 222° intake, 230° exhaust @.050” tappet lift
Centerline: ........................................ ..... 107° ATDC intake, 117° BTDC exhaust

bluedawg

If you havent bought the cam shaft you might want to call Chris Straub.

bluedawg

How do the fast burn heads compare to the rhs heads?

CheezMoe

Thanks guys! BlueDawg, all components are purchased, as the motor is in the car and running. The crank I already had and nobody could come up with a good reason not to re-use it. The Howards cam was highly recommended by several folks and I have roots in Wisc I like your thinking! I was hoping for ~475hp .

The question about the heads is a good one, and I never understood the whole "Fast Burn" thing. Different chamber shape, or just because the chamber is small? I'm not sure on the other specs of the fast burns but would bet the runners are 180 at best.

Interesting that the Chevy 383 is a slightly different bore and stroke than the original hot rodding version. First I noticed that.

Still would love to see a DD output on this if anyone out there could assist.

Flyinace3

I will run your combo in dyno 2000 this evening. Do you know the flow numbers of the heads and the cam timing events intake and exhaust open and close degrees? Also are your pistons domed or flat tops with valve reliefs?

bluedawg

It is interesting that gm uses a 3.8" stroke crank and besides gmpp you don't see people using it. The only thing about the crank is another member had the snout break. Is hp was a lot higher on his 383 and he thinks it was a big part of the fluid damper.

gkull

I have a 12 -15 year old Fluid damper on my more powerful 383. third different cam and rebuilds without a problem. 100's upon 100's of 1/4 mile 11.70 passes.


But anyway the 3.800 stroke is because of the standard 4.00 inch bore block.

As to fastburn heads. The GM has tiny valves limiting flow. Nearly all aftermarket aluminum heads have fast burn technology shaped chambers. that is why you only need about 32-34 degrees of timing

Flyinace3

Here is the results from dyno 2000 with the info you provided.
I used head flow data from Stan Weiss's web site as follows
.1 69/57
.2 134/101
.3 192/157
.4 236/177
.5 261/186
.6 268/190
.7 278/195



http://forums.corvetteforum.com/memb...0&ref=gnr-prev

Flyinace3

http://forums.corvetteforum.com/memb...&mode=gnr_rand

Flyinace3

CheezMoe

Flyinace3, that is awesome! Thanks so much! Close enough to 500/500 to call it 500/500 I think! The pistons are flat tops with 2 valve relief. I don't have the camcard or the flow numbers right at hand. Seems like you found correct flow numbers for the heads but I will double check. If you think the cam open/close numbers would have a significant impact on this output please let me know and I'll track them down ASAP! Thanks again this makes me feel really good about my build. It' supposed to be sunny and 80* with low humidity tomorrow. Going to hit the hills and give this thing a little work out!

Flyinace3

Your build is very similar to the build I am going to do this winter for my 1980. How is the performance of your 383 compared to a c5? How is the streetability and does this cam have a lope at idle ?

CheezMoe

Compared to a C5, other than obvious cold nature, and less refined, I would say this motor does not quite have the low end torque of the LS-1. With the C5 in high gear at 1500rpm, I can pull away from traffic. Need to be in the 1800-2k range to do that with the 383. It definitely prefers a a few more revs, and most certainly has much more high RPM HP than the LS-1. . Streetabilty is awesome. I tweaked the carb a little today and went out. In 1st you can just about take off from idle...just needs a little very slight goose. Idle is as advertised by Howards for this cam, ' Choppy" but not too lopy. I think it sounds and idles really good. So far I cannot get idle <1k with it loading up. Still working on tuning though. I took some video with good audio of the idle but cannot seem to get it uploaded to photobucket. I'll post up the link if I succeed.

I took a good drive today and did some hills and curves, lots of 3500-4500 between 3rd and 4th. The thing really likes to run in that rnage, so about 500rpm up from the Ls-1 sweet spot.

CheezMoe

Here is the vid of it idling in my garage!

http://s71.photobucket.com/user/doso...ca270.mp4.html

Flyinace3

Thanks for all the information and your car sounds awesome. My plan is to use a howards cam in my build but their I haven't found much info on them or many people that use them. There is just so many different options and directions to take in a engine build..

augiedoggy

Unfortunately dyno 2000 is extremely optimistic....you need to take it with a huge grain of salt. according to it I will be making 404hp and 434lbs of torque with my little voodoo 262 cam.....yet all the real dyno results I could find with similar speces components are closer to 350hp including lunatis... dyno 2000 even had my old school 268h cam with 218 /454 lift rated at higher than 400 HP with everyone said 330-350 was more realistic with my heads and compression.
It is a free download if you want to play with it yourself as I did to choose my cam last week. Just Google it...

Much of the stuff you posted makes no difference like brand of crank and double roller chain, and all the "forged and Molly" its nice for strength and longevity but like you already pointed out with the crank, is totally unnecessary when calculating power.... Your right that a stronger crank is totally not needed at your power point but neither are forged pistons right? They have more negatives than positives on a street engine...

pauldana

yea... sad but true ...small cam.... i would bet 400hp, which is still great!

bluedawg

I would think if thr rhs heads flow better than the fast burns it still make a legit 425, 430 horse.