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I unfortunately tore up a rod bearing in my '96 Vortec 350. Now I need some help with the options I have. The stock 350 wasn't turning the 40's like I needed it to anyway. The two options I am currently debating are dropping in a bigger motor such as a 454 or building up the stock 350. I was told that a Vortec 454 would be fairly easy 'drop in' swap and all the electrical and things would plug right in. But I havn't had anyone really confirm this. Next, If I were to build up the 350 what options do I have. I haven't really seen any perfomance parts for the '96 - up 350's. I was thinking maybe a little bigger cam and new pistons and rings to bump up the compression a little?

Any suggestions that any of you have would be great. Also are there any good websites on Chevy motor performance and buildups??
 

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Ahh A michigan guy. Im over in waterford which is Northwest of detroit about 45min. Anyways

Im not sure how much of a plug in a 454 will be but I dont think so. The small blocks have hte spider set up inside the intake manifold for the injectors. In this set up there is one central plug in the middle of the intake then fuel lines going from this central block down to the injectors. The injectors dont have electrical connections to open up solenoids in them to let the fuel go by all of this is taken care of at the main block. Also the vortec sbc injectors are really weird. No aftermarket replacement for them. Im pretty sure not 100% positive though that the 454 has a more conventional set up where the injectors are mounted on the outside with an connection to each injector. Though you'll want to verify that.

As for performance parts for the vortecs there are plenty. Its a good ole sbc. It is a 1 pc rear main seal and not a 2 pc rear main but this is not a problem. You want to stroke it? go 383 or 396? Not a problem. Id keep the stock heads as they flow well but Id port them so they flow excellent (280+ cfm on intake with little metal removal). Remember porting is not about maximum metal removal its about removing the material which gives the maximum return. Minimum material removal with a maximum return. Removing the least amount of material maintains a small port volume which increase port velocity which increases cylinder filling. Another thing to focus on is port bias. I can explain more if you want but right now thats just way too much typing :crazy: How much do you want to do? Whats your budget? Whats your truck used for? Whats your mod list? Answer these and we can help you.

Josh
 

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Discussion Starter #5
badburban,

Thanks for the info. I'm over by Grand Rapids actually about 30 miles North.
The truck is basically used for a toy now. I have a HP Dana 60 up front and a 14FF in the rear with 5.13,s and Detroits, spinning 39.5 TSL's. The motor was basically stock and the 4L60E has been 'upgraded' with a shift kit and corvette servo. I just wheel the truck around here so thats mud, sand, hills and afew rocks when I make it to the U.P. I just lost my job about a month ago and am in the process of starting my own business so I don't really have a budget for the project. I may just let it sit and do it as a winter project when I have more funds. I would really like to get to the 350HP or more range to help turn the rubber a little better, especially in the mud. I really don't have a whole lot of knowledge with motors, I have rebuilt a stock 305 about 10 years ago but that's about it. There's a little more info for you. Thanks for the help.
 

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Well If I would have read your sig I guess I would have known what you use your truck for :read: I used to live in and around GR for 6 years. Anyways. 350 flywheel hp can be had its not until you start pushing 400 flywheel hp that the stock injection system becomes a problem. So being as you are on the low dough side we'll be assuming its going to stay stock stroke though you can get a new scat stroker crank for about $200 :devil2: (I just cant help myself. I only think of going faster) Since you'll have to buy new pistons anyways. If you're willing to work on the heads and port them I can give you a much more in depth detailed procedure and a website with a good step by step procedure with pics. There is a lot power that can be had by working on the heads. Pretty much with a some more compression, well ported heads, properly matched cam, and a good tune an easy 350+ hp can be had. I do my own tuning for my TBI truck but unfortunately There is no program allowing the avg. joe schmo to do his own tuning on vortec trucks. If you were to drop a 454 in I wouldnt keep that 4l60e behind it. You'd have to upgrade to a 4l80e. Know Im not sure if you can mod the factory harness to work wtih the 454 (ie adding injector plugs etc).

Josh
 

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Discussion Starter #7
Yeah I was wondering at what point the current injectors and things become a problem. Are there bigger injectors that can be put in?? Or can the stock ones be setup to flow more fuel?? Like adding more pulses with the tune? I was already planning on a new crank because I am sure it is tore up. Isn't there machine work that needs to be done to the block when you stroke it? I would be interested in the porting info whenever you get a chance. I have ported a few Jet-Skis and Snowmobiles I imagine the concept is the same. Thanks for all the info so far. I'm trying to learn as much as I can. I'm going to try and forget about wheeling this summer :flame: and save some money and take the time to build the motor right this winter.
 

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Masher

Well about 350-400 hp they start to become a problem. I want to say the stockers are only 19 pph maybe 21 pph. The stock injectors and intake are really weird. If I can get my buddy to bring his camera over Ill get some pics of the injector set up. In the middle of the intake is a big plug. This plug goes to a main fuel block. Coming from the main fuel block is a small fuel line running down to the injector. Now all of this is on the inside of the intake. The intake is a 2 piece design with a composite upper half that pulls off and then a cast aluminum base. The injectors are very small and dont have any wires going to them because there is no solenoid in the injectors. On a standard injector (bosch style) there is a needle that sits on a seat. When the computer fires an injector it puts 12V to the injector which energizes a coil inside the injector which pulls the needle of the seat allowing fuel to flow by. This is not so in the vortec set up. First the injectors are tiny nothing like a bosch style injector. They dont fit into the intake runner from top side they "clip" in from the side into the intake runner. They are a pintle design. All of the firing of the injectors is taken care of up at the main fuel block where the big plug plugs in at. Now GM had a problem with the pintle design so they came out with a replacement set of injectors which arent bigger but they do have wires running down to them like a normal injector. No one makes anything bigger. But Ive just started my own business and Im going to try to come up with something better. Ill adapt an aftermarket carb intake and drill and locate injector bosses for a standard bosch injector and then I can get someone to make me direct plug and play plug which will plug into the factory one. Then the stock computer can still fire them. The only problem I think there might be is that there is no injector constant inside the vortec ecm. Or at least it hasnt been found yet. I know someone who works at street and performance electronics and he said he hasnt found anything yet. Know I dont right my own source code but there may be a way to modify the source code a bit and change the Injector PW calculations to use a user defined injector size. Some crazy thoughts running around in my head. Like I said Ill try and get some pics for you later on.

As for the 383 or any stroker. Yes the side of the block needs to get notched and some of the bottom of the cylinder liners will need to get notched. Not a big deal. You can even do that at home. Its not that hard with some time, patience, and a die grinder. Also the sides of some of the connecting rods may need to get chamfered to give cam to con rod clearance. Not a big deal either. Again something you can do at home to save some dough. More things you can do to save some dough is to drive out all the freeze plugs, remove oil gallery plugs, and install your own freeze plugs. There are alot of steps you can do yourself to save a few $$ here or there if you're on the low dough side.

As for head porting stuff here is that website

http://www.carcraft.com/techarticles/116_0306_vort/index1.html

This was written by Roger Helgeson who is a very well known and very knowledgeable about the subject. For porting I highly recommend getting some carbide burrs as they work great. THe main key to remember is that porting is not about removing the maximum amount of metal possible. Its about removing the minumum amount from the areas that produce the maximum increase. Bowl work and blending the bowls nicely into the seats can show a ton of improvement. Get a good 3 angle job on the seats. Thin and shape the guide boss and focus on port bias on the intake. One thing to focus on is the throat diameter should be about 85% of the valve diameter on the exhaust and about 90% of the intake valve diameter. The bowls should blend smoothly into the seats. ALOT of airflow can be picked up here.

By maximizing port bias you promote a really good swirl which increase low and midrange tq significantly. And because the air will be directed towards the center of the cylinder valve shrouding can be significantly overcome (not fixed but cheated). Dont focus on grinding the pushrod pinch as this area already flows very well. All that happens when you grind more metal then needed is you increase port volume which decrease port velocity. Which is bad. High Port Velocitys help to improve power across the board and especially low and midrange tq. Tq is what makes a vehicle feel fast. Having a big fat torque curve will make a vehicle very responsive and very fast not just peak hp numbers. Those are only for bench racing. And porting the intake is about metal removal in the proper places and not polish. A slightly rough texture helps to keep fuel atomized much better and only gives up a few cfm to a mirror finish as for flow but a mirror finish on the intake gives up hp on a dyno. The smoothest you will want would be to finish it with a 60 or 80 grit tootsie roll. Another common mistake is for first time porters to focus to much on the port floor. The port floor is an area of stagnant flow. THe majority of the flow is on the port roof and port walls on the outside of the bends of the intake port. Another thing that is not important is forming a smooth radius on the port floor where it bends down to the seat. This is for two reasons. A. Its an area of stagnant flow and B. Air will shear away from a wall with any more then an 8 degree bend so it doesnt matter. The best bet is to put a generous radius going up to the peak of the bend then you can almost drop it straight off. Now something that doesnt necesarrily apply to you but in wet manifold applications it actually pays to have the bottom of the intake port in the intake sit about .050 or more higher then the intake port of the head as this will help to break up the sheets of fuel that puddles in the port floor of the intake.

Also when you get your machine work done bolt the heads on the block remember where each head went. Then scribe the outline of each cylinder wall onto the bottom of each head from the bottom of the block. A bit of dykem on the heads helps to make the marks more visible. Sweep the combustion chambers out the the lines and polish the chambers. Having chambers polished to a mirror finish reflects more heat back into the combustion which means more power.

Now when working on the on the exhaust you want a mirror finish on it since it doesnt have to keep anything in suspension. Plus the mirror finish helps to reduce carbon build up. Again the port floor is an area of stagnant flow and the port roof is the highest flowing area. You can raise the port roof putting a slight D in the port.

Other small things to pay attention to. By running some hyper pistons you can run really tight piston to wall clearances because they dont expand very much. This keeps piston rock to a minimum which means you can tighten down your quench. Quench is the area between the piston top and the bottom of the head. .040 is a good but if you can go a bit tighter its better but .045 is acceptable. THe tighter quench may increase compression but it actually decreases your chances for detonation. Because of the small clearance it helps to eliminate rich and lean pockets therefore decreaseing detonation.

Also run flat tops whenever possible as piston crowns interfere with and slow down the flame front. THe gas just doesnt explode its a slow and controlled burn. In a combustion chamber the gas may only burn at about 150-180 ft/sec while dynamite burns at 2000+ ft/sec so Id say gas burns and doesnt explode.

But you have the right attitude. Take your time and do it right the first time no matter how long it takes. I dont like re-doing things.

Josh
 

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Discussion Starter #9
Wow, thanks again for the info. :worship: Yeah I know what you are talking about with the injectors I just got done replacing the intake gasket. I think that is what actually toasted my rod bearing. I guess I wasn't carefull enough :flame: I will defenitatley be checking out the porting website, thanks. Hey I was also looking through my Summit catalog last night and I really don't see any parts for the '96-up 350's everything seems to stop at 95? Do you know of any good websites for parts or on building up chevy engines?? Your buddy that you talked about can he reprogram the ECM?? I haven't found anyone that can do this. I really need to change it for the gears and tires I have on it plus I'm sure it should be tweaked now that I am playing with the motor. I looked into one of those handheld programmers but they only calibrate up to 4.56's and 38"s.

Thanks
 

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Yea he can reprogram you PCM. His name is Dean Pakowitz (SP?) and he works at Street and Performance Electronics in Alabama. Ive talked with him many times on another forum and email etc. Good guy. Another person I can highly recommend is Lyndon at Westers Garage. He's in Canada. I havent talked to him much just once or twice but I know many people who I trust that are extremely pleased with his results and as I recall he gives free re-programs as you mod.

Well what parts are you looking for. The vortecs are a good ole sbc. About the only thing different is the redesign of the heads and the injection system. Other then that everything is good ole sbc. The vortecs are roller cam's which is nice and the roller lifters so long as they spin good can be re-used and dont take long at all to tear apart and clean up. I buy alot of my parts at Summit because they have always taken care of me whenever Ive had a problem. No questions asked. Very liberal return policy though I have dropped quite a bit of money there. Shoot when they had hte grand opening of the new addition I drove all the way down there both weekends to check it out and buy stuff.

Josh
 
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