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new intake manifold --weekend project--

Discussion in 'Chevy Trucks' started by 85w/350, Apr 30, 2001.

  1. 85w/350

    85w/350 Senior Member
    Messages: 190

    Hey guys, I decided to go with an edlebrock performer inatake for my 350. I have never replaced an intake manifold before but i have little fear about any work I do on my truck being that I am mechanically inclined and i have a few mechanic friends to refrence if need be. Anyone have any cautions for me? Any suggested gaskets? Or other things I should take a look at / replace while I have the intake off? Thanks for any two cents you have to offer.
  2. Mudbug44s

    Mudbug44s Junior Member
    Messages: 11

    Manifold swap

    Hmmm, I dont have any real tricks for changing intake manifolds. Just follow the directions to the letter, mark the distributor(Both the rotor position and the housing). Dont use the rubber end gaskets, use a 1/4" bead of RTV blue on the ends instead.

    Fel Pro has a neat gasket with a small screen across the runner openings, the theory is that they will help atomize fuel that is falling out of suspension. I Put them on a race Vega that I had and I liked them (I dropped a Nut down the intake and the screen kept it out of the valve). I cant vouch for the performance gain but some gizmos and gadgets are kinda neat.

    I just put an RPM air gap intake on a friends truck. I switched to ARP 12 point bolts and it sure made it nice for tightening the center two bolts on each side. Kinda expensive but what the heck.

    There is an old circle track trick of painting the bottom of your intake(The underside) White. The theory is that it will reflect more heat and keep the intake charge cooler. I dont like the Idea of paint peeling off the intake and falling into the lifter valley, it could cause a BIG headache.

    One last thing, Try to keep all the old gasket material out of the lifter valley. Stuff some rags into the intake holes in the head to keep them free of dirt. I use a shop vac to clean out the whole area when I have it all scraped clean. Good luck, and Have FUN.

  3. 85w/350

    85w/350 Senior Member
    Messages: 190

    Thanks for the reply. Wierd that they paint the underside white..what color does it really matter that the underside is if its never reflecting light. If its heat seams like just the paint coating is doing it. i personally dont like the idea either. I'll be sure to use the RVT Blue and I am cautious with the cleanliness of any project i approach. :)
  4. Garet

    Garet Senior Member
    Messages: 106

    some things

    Make sure that the gasket does not get out of place when you install the manifold. I had it do this once which fouled everything up. Also, make sure you have the torque pattern. This will aid in getting the thing on straight and proper. If the Fel Pro gasket is expensive I wouldn't use it. I would just go with a standard gasket. Besides making sure you have a good clean surface, that's about all that really matters.
  5. 85w/350

    85w/350 Senior Member
    Messages: 190

    I'm not worried about the expense of a gasket...I have been contemplating a new intake for quite some time now. I think ALOT about things before I begin work on them on my truck so when i do it i get it done right the first time. So a good gasket is all i will settle for despite the extra few bucks. Think about it...the intake is a major part of an engine and anything that can get in and out thats not going in the right place is BAD. Thanks for suggesting the torque specs and pattern...Anyone know of any amount of time i should definately let it sit before starting it? Maybe the liquid gasket if by any possibility wouldnt be dry would be at a later period of time?
  6. MTCK

    MTCK Senior Member
    Messages: 346

    When I put that manifold on my truck, I believe it sat for about 2 weeks befor the engine was fired, but this was mainly because the body was off the frame at the time. I'd imagine it would be fine after 2 hours or so. They only thing you'd be waiting on is the RTV at the ends, and they only see oil, not coolant right? To be on the safe side maybe let it sit over night. I don't really think it's necessary though. It's hard to not drive something after you make an improvement to it :) Good luck.

  7. 85w/350

    85w/350 Senior Member
    Messages: 190

    How do you like the manifold? I emailed the people at edelbrock with my engine specs and they said probably a 10-15hp increase. Better throttle response. My engine is basically stock just a fre flowing exhaust system. I can't wait to get to the weekend and I know its gonan be hard to just let it sit... :)
  8. MTCK

    MTCK Senior Member
    Messages: 346

    I like it, the throttle response is deffinetly better, along with the low end torque. I was planning on putting a 383 in my truck, so I put a performer 750 carb on it, and it's way too big, but by rejetting it, it works ok. I also am running dual 3" exhaust with hedman headers, and flowmaster mufflers, and a hotter ignition. I did all the mods at the same time, and it deffinetly brought the engine to life. Drivability is a lot better. Let us know how you like yours.
  9. 85w/350

    85w/350 Senior Member
    Messages: 190

    Sure thing...I also have flowmaster exhaust and MSD ignition...all the other small things are there I just think this is going to connect everything else. Thanks for the feedback!
  10. Alan

    Alan PlowSite.com Addict
    Messages: 1,393

    I've got a Performer intake on the 350 in my GMC 5500. 4spd with 2 spd rear. Granted, it's geared low, 6.65 high, 8.82 low range, but it pulls something fierce. I try to keep revs between 2,00 and 3,500. Grossing 21,000 I can come off a dead stop in second low without touching the throttle. Carb is a 600 Holley with electric choke.
  11. 75

    75 PlowSite.com Addict
    Messages: 1,382

    I've also got a Performer on my truck (C-35 dually, 350/RV grind cam/Quadrajet 4MV/2" dual exhaust with glasspacks & stacks/T-400/4.10 rear) which weighs in at around 8,000# + and I'm happy with the combination.

    I put the manifold on during engine assembly (on a stand) so I can't offer any tips for an on-board manifold swap, but I will say I used the rubber end gaskets with no problems. A handbook on rebuilding small-block Chevys suggested doing the following:

    Use 3M Weatherstrip Adhesive or equivalent to secure the rubber seals to the block. Make sure the surface is clean & dry, put the glue on the block and then set the seals in place. Be careful when placing the manifold gaskets on the heads - a tab at each end of the gasket goes into a matching notch on the rubber seal. Use a blob of RTV at these 4 spots, as well as a thin bead of it around each water-jacket hole.

    Good luck with the swap - I think you'll be pleased with the results.
  12. 85w/350

    85w/350 Senior Member
    Messages: 190

    Thanks 75 for the indepth instructions...I appreciate it! Can't hardly wait its almost the weekend! :)
  13. 84'GMC4x4

    84'GMC4x4 Member
    Messages: 42

    I, much like everyone else here, also have the performer intake on my 350. I used the rubber end gaskets twice, once when i installed the intake new, and again recently when i replaced my heads. havent had any trouble with them either time. Like 75 says, match up the tabs and give a nice blob of rtv in those corners, and you shouldn't have any trouble.

    have fun,
  14. raceman6135

    raceman6135 Member
    Messages: 61

    A couple of other things to watch out for:

    1) make sure to drain the coolant as much as possible. It's a heck of a mess if you pull the intake and haven't drained the coolant. Water in the oil is bad, m'kay?

    2) Use Fel-Pro "Print-o-seal" gaskets, not Perma-Torque Blue (or equivelent). The Print-o-seal type of gaskets have RTV embossed around the passages (air and coolant) already. The Perma-Torque type of gaskets are NOT designed for aluminum intakes; they are used for cast iron intakes. You can actually "dent" your brand new aluminum intake with an improper gasket!

    3) Keep an eye on your plugs after swapping manifolds. The mixture distribution will be better and it's not uncommon for the engine to run lean with the better manifold. Fatten the jetting and you'll be able to use less "foot" to make the vehicle travel at the same speed, thereby increasing fuel economy.

    4) Put in a new thermostat while everything's ripped apart. Better to spend the three dollars now than later!

    5) Use washers under the heads of the intake's mounting bolts. This will help you apply torque more evenly and will keep the intake from getting chewed up.

    6) Check your oil pressure sender unit at the back, driver's side of the block. If it's leaking, fix it now. You'll have lots of room and will be able to tell where a leak is coming from should one develop.

    7) Work the throttle by hand before firing the engine. Sometimes a new carb base gasket will hang over into the plenum and contact the throttle blades. Also, the increased height of the carb mounting surface may cause small misalignments with throttle and/or transmission kickdown (if applicable) linkage.

    8) When installing the intake manifold bolts, put a small amount of non-hardening sealer on the threads. As you will see, the bolt holes are open into the intake valley, and I've had oil migrate up the threads of the bolts and pool on my new aluminum intake. Not pretty, and it didn't smell good, either.

    9) Replace all your vacuum hoses if they're more than a year or two old. You may also have to reroute some lines, depending on where the vacuum fittings are located on the new manifold vs. the original manifold.

    Sorry to be so long winded, but I've done this swap LOTS on all sorts of engines (not just SBCs).

    Have fun!
  15. 85w/350

    85w/350 Senior Member
    Messages: 190

    Thanks for being long winded...your reply is just in time because i have straightened all the other things out both with the truck and finacially to play some more...I was just thinking about the project again recently and its looking to be done in the very near future maybe even this weekend :)