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Ok , so you just got yourself a new Holley Throttle Body Injection. The new part comes with a step down gasket , but I choose to bore the Manifold out. I previously have run with the step down gasket and Im excited to see an improvement in air flow versus how it used to be. While I had the intake off, I went ahead and ground deep into the intake and shaped the Intake to head passage radiaus. Its somewhat involved so if you dont have the proper equipment then I sugesst you think twice before starting this. I hope to ease the task for you , the person pondering this option. Here we go.


First take off the negitive cable on the battery .Ok begin removing the serpentine belt. A 13mm and a rachet on the tensioner is in order dude. Drain coolant(optional). Next pull the male sensor connectors off the following. A/C compressor, IAC valve,TPS,Coolant sensor,knock sensor. Disconnect the fuel lines from the TBI. Remove TBI throttle linkage,save the clip,strand it over the brake booster, pull off vaccumm lines,take off TBI set aside. Take out all 3 A/C compressor bolts ,they are underneath it, 13mm.Remove upper compressor to manifold brace 13mm. Save nut. Let it hang on the fan and fan area. Loosen Alternator bolts on the top drivers right10mm, and back passengers left(facing motor)10mm. Put screws back in alternator. Loosen clamp and pull on coolant hose(upper).Unscrew Coolant to Manifold bulkhead and brake booster bulkhead. Sway them out to their respective sides.






This is a drivers side engine hoist bracket. This bracket is located on the exhaust manifold. When you begin to remove the drivers side Valve cover, you need to take this off. Its held by two bolts. One is a stud on the manifold at the Oil dipstick sheath. The other is to the front.When you remove a bolt from anywhere in the motor, you should thread it back in if possible. This helps you remember where it came from as well as holding it so it wont get lost. With valve covers off , unscrew vacumm advance box next to coil. Grab a 15mm sockect ,long extension,rachet, and holding at angle loosen distributor hold down bolt. !Do not remove! Remove 6 13mm manifold bolts and 4 10mm manifold bolts. Using a long pry, chase upper front lip with it and pry gently. It should pop up slightly.Coolant will leak if you didnt drain the coolant, and you'll need to soak it up in the valley and change the oil.
Being patient wiggle it round a few times and pry in front again , but very gently. Assuming the passenger rear stud didnt come out with the nut and two washers(Was tricky to remove in the first place) reach near coil and unthread distributor hold down nut , but not all the way , say 1/2 inch or so. This will allow you to pop the rear of the manifold out , but you dont have to pull out the distributor and fool with dropping it back in.If It wont pop up to clear stud, you have to unthread the hold down bolt a little more. Also turn the distributor so the aluminum housing edge that has a slight reccession come in the area in question. It should now pop up, but take your time.







You will need a air grinder or a Rotozip and some sanding skins such as one available from standard abrasives. Use a Machinists marker and using a grinded and flush gasket, mark the manifold top so that material removed will totally match the size profile of the New TBI, or lets just say as best you can do, after all that manifold wasnt easy to take off, and It'll be twice as hard to put back on with setting the valve lash and all(dam 2.8 gaskets, the pushrods go through the gasket).







I began with a air grinder,taking the material off with a slight taper favoring the top more than the deeper part(coolant passages reside behind the bore wall so keep in mind your working around about a 1/4" wall.







The air grinder just wasnt cutting it. This roto zip is a great tool for fast powerful grinding. Be careful it really nasty if you dont handle it with some sensetivity.I really gave a hard bore deep into the manifold . I occasionally wiped off the aluminum dust and set the TBI on the manifold and looked into the bores to check my progress. I really swiped it good with the rotozip and removed air flow disturbing flash and defects.












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