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Good mods for new 350?

Discussion in 'The Garage' started by Buzz, Feb 15, 2004.

  1. Buzz

    Buzz Registered Member

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    I have a new crate 350 but would like some added performance ( you know the drill: hp/torque/mpg). Need suggestions as to what I need to be looking towards.
     
  2. SUBFAN

    SUBFAN 1/2 ton status

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    Figure out what you really expect the engine ro do.

    List all the current specs of the engine, truck, and/or the future specs you are reaching for.

    Decide what skill level you have to perform such mods as headers, cams, intakes, gears, carbs, ignition, atc. etc....
     
  3. monsterjim

    monsterjim 1/2 ton status

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    Got to make it breath good, so some good headers and a good carb should be first. You can gasket match the exhaust side of the heads to help them flow better, depending on if you want low end torque or rpms, will determine what intake to go with, weather it be dual or single plane, or a high rise. A good ignition system (MSD) including a 6AL box, distributor and coil, with some thick plug wires couldn't hurt either. It all takes money, but getting the heads machined is the best way to get some hp. Just don't cut corners on rod bolts or valve springs. What do you plan on doing with the motor, and how much do you have to spend?
     
  4. 350350

    350350 1/2 ton status

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    Something many people overlook in any application is the air intake. Whether Fuel Injected or Carb'd, Your engine wants fresh, clean, cool air. Most of us (I'm guilty as charged when it comes to my K5) overlook this and just slap on a nice-looking gigantic open element chrome air filter that breathes in all the hot engine bay air that your headers and radiator are putting out.

    You can do a couple of things here, and it can be really expensive or really cheap, your choice. If you build it yourself out of common PCV from your local Lowe's or Home Improvement and/or from large exhaust pipe, it can be real cheap. If you buy ready-made kits that are a lot nicer-looking and might fit a little better, get out that credit card!!!

    /forums/images/graemlins/bow.gif The first way is a dual-snorkel air filter setup that will breathe really well and look pretty cool too. You basically take a stock air cleaner and cut out another hole to run dual outlets to locations on the front of the vehicle somewhere that they won't pick up bugs or birds or mud, etc. The dual inlets are necessary simply for volume. With dual inlets you're sure not to choke off the air supply for even a big cube motor. I've seen people use everything from dryer flex tube to exhauset flex tube to PCV and exhaust tube, and don't overlook factory stock pieces at the junkyard that will look nice and might even fit your application to some extent. In any case, keep in mind that your motor flexes inside the body, so flex of some kind is necessary somewhere between the motor and body for this application.

    /forums/images/graemlins/bow.gif The second way is to simply get out the credit card and buy an aftermarket setup that's designed to do the above for your application. It will do basically the same thing, will look like it's supposed to be there, almost like a factory application, but will cost a lot more. It's up to you to decide whether it's worth the cash or not. You might look over the rest of your ride and ask yourself if it would be out of place or not... /forums/images/graemlins/whistling.gif

    /forums/images/graemlins/waytogo.gif Of course, the great thing about either of the above is that you can kill two birds with one stone. While doing either way above, you can do a snorkel setup to keep your air coming in just in case you submerge your rig up to the headlights!!! So you not only get a few hp from the cold air intake, but you get the piece of mind that you're not going to trash that awesome new crate motor if you go in a little too deep!

    Just IMHO.

    Good Luck!

    /forums/images/graemlins/peace.gif P.S. I forgot to mention that in my '78 Malibu with a 406, a dual snorkel homemade cold air intake setup was worth 0.3 seconds in the 1/4 mile at the dragstrip. I went from a clean 14.11 to a 13.82!!! Just backing my claims with slips!!!
     
  5. Paxx

    Paxx 1/2 ton status

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    Where exactly would you run the ducting to to avoid sucking crap in? This is the one thing that always has me wondering. Pics are great too /forums/images/graemlins/waytogo.gif
     
  6. Z3PR

    Z3PR Banned

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    [ QUOTE ]
    Where exactly would you run the ducting to to avoid sucking crap in? This is the one thing that always has me wondering. Pics are great too /forums/images/graemlins/waytogo.gif

    [/ QUOTE ] Get a snorkel kit.
     
  7. 350350

    350350 1/2 ton status

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    [ QUOTE ]
    [ QUOTE ]
    Where exactly would you run the ducting to to avoid sucking crap in? This is the one thing that always has me wondering. Pics are great too /forums/images/graemlins/waytogo.gif

    [/ QUOTE ] Get a snorkel kit.

    [/ QUOTE ]

    Agreed!

    If you don't think you need the snorkel, or don't like the looks, there are several options. I'll go out and investigate my K5 later today to see what it has in store and try to take some pics... But in general:

    /forums/images/graemlins/thinking.gif There is usually somewhere in a fender that you can mount your ducting to. The fender usually has an opening lower, under the engine compartment, where it can draw fresh air, without sucking bugs and birds and such. Depending on how deep you travel in mud and water, this could be a bad idea...

    /forums/images/graemlins/thinking.gif There's also usually somewhere in your radiator support that you can cut a hole and run your ductwork through. You might have to put a baffle in front of it or try to place it behind other existing structures to keep from sucking bugs and such...

    /forums/images/graemlins/bow.gif The coolest I've seen is using a section of your existing air inlet just in front of your windshield. I've never done this before or had it apart, but basically I believe it's where your heat/AC pulls its air from. You split it so the heat/AC can still pull air, but you can then use a portion to run your Cold Air Intake through. Almost like a snorkel too because even though it's not much higher than a mount behind your headlight, a lot of times it's the 'nose-in' that dunks your truck and drowns it.

    Like I said I'll investigate some possibilities on my K5 and try to snap some pics.
     
  8. 350350

    350350 1/2 ton status

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    GM may have actually thought ahead for you!!! Here's a picture of the inside of my engine compartment on my '77 K5.

    [​IMG]

    There's a hole punched but not cut through. It's the same on both sides of the radiator in the radiator support. I'd say this is a perfect place to run your ductwork. It comes out right behind the grill with nothing in the way of the incoming air. I'd say a couple of things about mounting here:

    /forums/images/graemlins/deal.gif Ram Air! Useless on the trail, but on the highway probably good for a couple of mpg. Get used to changing your air filter more often though because you're going to catch everything that you normally see on your windshield.

    /forums/images/graemlins/deal.gif If you don't like ram air, just build a small flat plate a few inches in front of the air inlet so that it doesn't obstruct air from going in, but so that it will stop dirt and bugs and such from going straight in your ductwork...

    IMHO. /forums/images/graemlins/waytogo.gif

    There are like a zillion other ways to do it though so I'd be glad to hear others chime in! /forums/images/graemlins/ears.gif
     
  9. tecton

    tecton 1/2 ton status

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    id use screens
     
  10. 84gmcjimmy

    84gmcjimmy 1 ton status

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    how come you can't buy those snorkels for chevy's or GM's? Has any one seen the TTC for this year? A couple of guys had a neat snorkle thing using flexible pipe, how would you do that?
     
  11. Paxx

    Paxx 1/2 ton status

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    Ya the snorkel looks like it would be ripped off in a second with all the tight trees around here. I do not anticipate deep water crossings all that often but I do hit the mud from time to time. I'll go see if my truck has those pre punched spots that might be what I end up using.

    The other idea that I had was to run it to the rear corners of the hood, cut out a square at each corner and have it pull air from there. You could build some kind of reverse scoops to keep water from entering the front, but I was always a little unsure on how to keep the water that hits your windshield from flowing in there after your wipers push it away.

    That make sense? /forums/images/graemlins/grin.gif
     
  12. Paxx

    Paxx 1/2 ton status

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    Just went out and checked those pre punched holes out and the one on the passenger side is 3 3/4" wide, while the drivers side is only 3" wide. /forums/images/graemlins/thinking.gif Not too sure why that is.

    /forums/images/graemlins/dunno.gif I guess you could always cut them a little bigger if you had to though.
     
  13. 350350

    350350 1/2 ton status

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    [ QUOTE ]
    Just went out and checked those pre punched holes out and the one on the passenger side is 3 3/4" wide, while the drivers side is only 3" wide. /forums/images/graemlins/thinking.gif Not too sure why that is.

    /forums/images/graemlins/dunno.gif I guess you could always cut them a little bigger if you had to though.

    [/ QUOTE ]

    You can get hole saws at your local home improvemnt stores in any size you want pretty cheap... I'd go with 4" just to be safe!!! /forums/images/graemlins/peace.gif
     
  14. 350350

    350350 1/2 ton status

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    [ QUOTE ]
    The other idea that I had was to run it to the rear corners of the hood, cut out a square at each corner and have it pull air from there. You could build some kind of reverse scoops to keep water from entering the front, but I was always a little unsure on how to keep the water that hits your windshield from flowing in there after your wipers push it away.

    That make sense? /forums/images/graemlins/grin.gif

    [/ QUOTE ]

    Have you ever seen a 'Shaker' hood scoop setup? The hood scoop stays on the engine and the hood seals around it when it shuts? The rain water runs out the bottom of the shaker and out a tube down the frame somewhere. You could make your own setup like that under each corner of your hood like you were talking, only not quite as complicated.

    Maybe you make a box under each corner of the hood and the bottom of the box is made of a grate to let the water/mud/bugs/etc fall through. Plumb your air duct into the front of the box so it catches little if any of the water and crud. Then if you want to be fancy put louvers in the hood above the boxes. Would be cool and unique. I'm making this up as I go and haven't seen anybody do it before but just building on your idea above. Don't see why it wouldn't work. You'd have to make sure the air would flow easier through the hood than through the grate so that you'd still be getting more fresh air than underhood air though... There's plenty of room under there to build. /forums/images/graemlins/thinking.gif
     
  15. 78GMCJIMMY

    78GMCJIMMY 1/2 ton status

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    [ QUOTE ]
    [ QUOTE ]
    The other idea that I had was to run it to the rear corners of the hood, cut out a square at each corner and have it pull air from there. You could build some kind of reverse scoops to keep water from entering the front, but I was always a little unsure on how to keep the water that hits your windshield from flowing in there after your wipers push it away.

    That make sense? /forums/images/graemlins/grin.gif

    [/ QUOTE ]

    Have you ever seen a 'Shaker' hood scoop setup? The hood scoop stays on the engine and the hood seals around it when it shuts? The rain water runs out the bottom of the shaker and out a tube down the frame somewhere. You could make your own setup like that under each corner of your hood like you were talking, only not quite as complicated.

    Maybe you make a box under each corner of the hood and the bottom of the box is made of a grate to let the water/mud/bugs/etc fall through. Plumb your air duct into the front of the box so it catches little if any of the water and crud. Then if you want to be fancy put louvers in the hood above the boxes. Would be cool and unique. I'm making this up as I go and haven't seen anybody do it before but just building on your idea above. Don't see why it wouldn't work. You'd have to make sure the air would flow easier through the hood than through the grate so that you'd still be getting more fresh air than underhood air though... There's plenty of room under there to build. /forums/images/graemlins/thinking.gif

    [/ QUOTE ] /forums/images/graemlins/peace.gifYeah Buddy! /forums/images/graemlins/peace.gif /forums/images/graemlins/k5.gif
     
  16. Paxx

    Paxx 1/2 ton status

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    Ok so you build two boxes with 4" inlets at the front, have the grate start just below the inlets. Underneath the grate have it shaped in a funnel type design with a hose at the bottom that exits somewhere just outside of the engine bay.

    If the boxes mount permanently to the hood and the drain hoses contain enough slack that when the hood is opened they are not pulled too tight and same with the 4" heater hose or whatever you run from the housing to the boxes, then you wouldn't need to worry about the boxes sealing properly against the hood.

    If the drain hose is restrictive enough almost all the air should be introduced through the large opening at the top.

    The new concern though might be that in deep enough water to submerge the drain opening the system might have enough pull to suck in water through the drain? If a place could be found to mount the drain hose where it will remain high enough to stay dry, yet low enough to still drain properly the problem might be solved.
     
  17. Paxx

    Paxx 1/2 ton status

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    I took a look under the hood again and saw that the hood overlaps the firewall at the back. You would have to move the boxes in a few inches or cut into the firewall and incorporate the box inside of there somehow. Probably be easier to move the boxes but it would look a lot prettier in the end if you could do it in the firewall. Not to sure what is behind the firewall in the corners either though. /forums/images/graemlins/thinking.gif

    Definitly got me thinking about doing this though.
     
  18. dyeager535

    dyeager535 1 ton status Premium Member

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    [ QUOTE ]
    Just went out and checked those pre punched holes out and the one on the passenger side is 3 3/4" wide, while the drivers side is only 3" wide. Not too sure why that is.

    [/ QUOTE ]

    Must be an 19XX (what year are you taliking about?) deal then, because my '81+ core support is identical on both sides. I know because I knocked the piece off, and swapped the plastic piece from the passenger side right to it. (IIRC, this was done because 6 cylinder models get air from drivers side)

    GM already thought of induction problems though, the '81+ trucks have a piece of plastic that locks into those holes (4 fingers on the plastic piece, raised bumps that they lock into in the core support) that prevents it from being "Ram Air" but it's still cool outside air, and keeps all kinds of debris and water out of it. Not if you take it deeper than the headlights, but if you do that, get a real snorkel.
     
  19. Paxx

    Paxx 1/2 ton status

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    1979
     
  20. 350350

    350350 1/2 ton status

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    [ QUOTE ]
    Ok so you build two boxes with 4" inlets at the front, have the grate start just below the inlets. Underneath the grate have it shaped in a funnel type design with a hose at the bottom that exits somewhere just outside of the engine bay.

    If the boxes mount permanently to the hood and the drain hoses contain enough slack that when the hood is opened they are not pulled too tight and same with the 4" heater hose or whatever you run from the housing to the boxes, then you wouldn't need to worry about the boxes sealing properly against the hood.

    If the drain hose is restrictive enough almost all the air should be introduced through the large opening at the top.

    The new concern though might be that in deep enough water to submerge the drain opening the system might have enough pull to suck in water through the drain? If a place could be found to mount the drain hose where it will remain high enough to stay dry, yet low enough to still drain properly the problem might be solved.

    [/ QUOTE ]

    On the firewall issue, you could build the boxes forward as far as necessary to clear the firewall on the inside of the engine bay, then louver the hood all the way back to the windshield simply for looks. I think that would look but that's just IMHO. /forums/images/graemlins/cool.gif
     

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