Sting Raycin

Ok, this is for my 67 Chevy c-10. I am buying a 96 2500HD with the Vortec 350 and 4L80e for a drive-train transplant. I am thinking about stroking the motor to a 383. I would like to use the existing injection, run off of pump gas and keep the emissions control working right. I know I will need to have the computer reprogrammed. What head work will I need to have done? Where can I get a good 383 kit from? What machine work is necessary on this block? Any other items I should be aware of? Will I need a different throttle body? injectors? What kins of a cam should I put in. I have lots of experience with the 96-00 5.7L, but never stroked one before. Any info you guys can give me is greatly appreciated.

CFI-EFI

The actual stroking is the same as the engines you are familiar with. You can buy a kit, or you will need a 1 piece rear seal crankshaft, rods and/or pistons, and a damper and flywheel if the crank isn't set up for internal balance. The fact that this is a vortec engine doesn't change the basics.
Check rod bolt to cylinder bottom, oil pan rail, and camshaft clearence. Screw together, and GO!
Head work, cam, TB, injection, and computer mods all depend on where you want to go. Good luck, and...

RACE ON!!!

Sting Raycin

How about this crank?
http://store.summitracing.com/partde...D51%2D05%2D002
What do I need since it is externally balanced?

Sting Raycin

Ok, now I see where it says I will need a 400 balancer and flexplate.

CFI-EFI

That is a perfectly fine crank to start the process. The key to the 400 flywheel or flexplate and damper is the "external balance". For more money you can buy internal balance cranks. I wouldn't think that any application that would successfully utilize a cast crank, would benefit frim the costly internal balance. The spec sheet also says, for 5.7" rods. If you reuse your 350 rods, you will need pistons. On an engine that doesn't need boring, the 350 pistons can be reused by switching to 400 rods. It sounds like THIS crank won't have counterweight clearence with the shorter (5.565") 400 rods. Decisions! Decisions! Good luck, and...

RACE ON!!!

Sting Raycin

Ok, so I can use my existing 5.7" rods with new pistons or get new 5.565" rods and use the existing pistons and my crank selection will be based upon that choice. Correct? Is there any advantage to either set-up, other than cost savings by using existing parts? (obviously if the cylinders need bored the new pistons would be the way to go)
Also reusing the existing vortec heads with 64cc combustion chamber how will my original compression ratio of 9.4:1 be affected. I assume it will be higher with the longer stroke. Will this screw with my ECM and emissions or will the reprogram take care of it? Do I need dished pistons to keep the compression ratio down?
*edit* I found that flat pistons will give a 10.34 compression ratio, while pistons with a -12.5cc dome (dish) will give 9.67cc compression ratio. I have still have my original question of whether the new compression ratio could be compensated for with a reprogram. *edit*

Also what cam should I run for a street engine, I know it has to be kept somewhat mild for the computer. I know if I go far enough with the cam my heads will need some mods, but I don't know if they or the engine control will limit first. If it is the heads I can do what ever they need.
I know I have more room to play since this system operates primarily from a MAF with MAP as back-up not primary, but I am unsure of the limits this system can be pushed to.
I am not looking to build a super-high performance engine here, but I would like a good base I can add little things to later.
What would your predictions be as far as horsepower and torque on this set-up? ( I know it is difficult to say given the generalities, but take a ballpark guess.) GM advertises 415 lb-ft of torque and 325 hp on their crate with a TBI set-upand 196/206 duration cam. I should do a little bit better with the Vortec CFI right? I would even probably use a little more radical cam if I could.
For this project I want a smooth running engine with the conveniences the FI will provide, but at the same time something a little custom to set it apart from the Vortec drop-ins I have been doing. It is important that is uses the 96-00 Vortec FI, since I want to use it as somewhat of a showcase for what I can do with the system.
Sorry to ask so many questions, but since I found someone knowledgeable I am going to milk it :seeya



[Modified by Sting Raycin, 4:54 AM 10/1/2003]

Sting Raycin

What do you think of the nodular iron crank # CK383CL on this page http://www.speedomotive.com/NEW%20CRANKS.HTM
It shows:
CNC machined to provide superior tolerance.
All journals are micro polished to 5 RMS.
Generous 0.125" journals radii ro disperse stress under high load.
Larger chamfer at oil holes for better lubricating.
Each crankshafts has been magnafluxed and ultrasonic tested.
External Balance

Part# CK383CL Engine: GM350

DESCRIPTION: Chevy 350, Modified, Main 2.4490", Rod 2.1000"' Stroke 3.750"' Weight 55lb., 1 peice seal, year 89-98. External Balance.

CFI-EFI

Technically, the classic 383 is a .030" over (4.030" bore) with a 3.75" (400 crank with cut down mains) stroke. A standard 4.00" bore would yield something like 377 cubic inches. The silly 7 cubic inches is relatively irrelevent. IF you don't have to bore, the 400 rods might be a cheaper way to go. *I*, along with most others on here, prefer a long rod. For your stated purposes a 400 rod would be OK, but the 350 rods would be preferable. The (5.7") 350 rods MAY have some clearence issues that the (5.565") 400 rods wouldn't. There is more different between those rods than simply the length. After all, the 400 rods clear everything in a 3.75" stroke 400. But don't sweat using 5.7" rods. Those and longer rods, still, are used every day. Just CHECK for clearence.

If the numbers are correct on the compression ratios, I think I would gamble with the flat top pistons. Do the math yourself. Have the block decked to provide .035" - .040" piston to head clearence with the head gasket of your choice. If necessary, the compression ratio can be lowered by unshrouding the valves (enlarging the combustion chamber). The close proximity of the piston to the head (squish area) will actually discourage ping, knock, or detonation. Lowering the compression ratio by increasing the head gasket thickness is NOT the way to stop knock.

I think I would pick a cam in the 210*-214* duration range @ .050" lift. With your roller cam this should get to .500" lift or so. Make sure your vortec heads can handle whatever lift you select. I think they may need the valve guides shortened.

My name is at the bottom of the compueter knowledge list, but I think this set up may run just fine with no tweeking. An optimised program is likely to improve it, but I question the necessity. Mainly, it's the cam that causes the need for tweeking. Your MAF system may be able to compensate. That's my two cents, for now. It's worth every penny you paid for it. Good luck, and...

RACE ON!!!

Sting Raycin

Thanks for your replies. From your info and info I have found in specs, I have got the answers for most of my questions. I still need to research further into the modifications I will need to the injection system, but I am well on the way.
I am going to install the engine tranny combo as it is now. Get everything running properly, and then take the engine out and stroke it then. I just want to get my game plan set right now so I can start collecting parts and make sure I know what I will need.
:seeya
Jason

Smokehouse69

The engine you are planning is similar to a series of articles in Chevy Hiperformance last year. Here's a link to the first of those articles, the rest of them are linked off that page. http://www.chevyhiperformance.com/techarticles/57841/

Sting Raycin

Actually I have read those articles. They are on a GM crate 383. Articles were informative and gave me some good ideas. :seeya