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TPI -> Carburation!!!

Good times, folks!  It can be done!  I will be doing a complete photographic How-To for the semi experience mechanic, but for now, here is info you NEED TO KNOW!  This stuff that is barely hinted at, or I learned from experience.  I found no good source for this info.  If you have any questions, or want to add any info, give me a ring... er... type at

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This isn't an all inclusive how to.  It is a write up on my particular swap in which I tossed on a Holley 750 cfm carburator.  I am assuming all holleys have a similar throttle bracket setup.  For any other carburators, your on your own.  If anyone has any Edelbrock/Carter or Demon specifics, or knows a better way to do anything, please email me!  Also, this engine is an 88 350 with a stock tpi system and a non integrated distributor coil.  There are some differences across the years!

It can be done, I did it.  I'll throw out some info I wish someone would have told me:

Parts Selection:
Distributor- a roller camsaft needs a special gear on the distributar so one doesn't chew the other up.  The best distributor I found is the GM Performance Parts one (p/n 1104067, 190$).  It has the right gear, and it is a good high performance model.  Car craft used it out of the box in their 520 horsepower 350 engine.  You need to replace the distributor; you cannot use the TPI one!

Manifold- Get one with the 87-up bolt angles.  I used an 86 down manifold, and dremeled mine out, but it was a big pain, and the bolts don't sit right anyway.  Weiand and Holley offer good manifolds that'll fit.  Edelbrock only has the Performer, and this isn't a great high performance manifold.  You need a manifold designed for the 87 up cast iron heads.  87-up aluminum heads had the conventional bolt pattern, and will not work.  (Thanks to March 2001 Car Craft for image!)

Also, along the runners I had to grind off some material because there was a ridge on my heads. You may or may not have to do this.

Carb- unless you are planning more engine mods later (heads, camshaft, stroker), go with a 600-650 cfm carb.  This will help drivability and gas milage, and you'll be much happier all around.

Fuel pump-  get an electric one.  Everyone says use the mallory 3 port with your stock pump, but this thing is worthess in my experience.  You need to keep the pressure on mine down to 4 psi so the pressure doesnt spike SEVERELY.  The pressure will still spike periodicly.  Also, none of the fittings would hold the pressure.  It leaked severly, and I had to JB Weld all of the fittings and plugs in place.  Get a electric pump that mounts neer the tank, and put a regulator up by the carb.  Most people say you dont need to remove the stock in tank pickup even if you go this route.  You will need to change the wires that power the fuel pump.  The relay will not work with the ECM not in use. This option will work great, and holley sells a fuel pump that comes with a regulator for the same price as just the mallory regulator.

Air Filter- drop base 14x3 works fine.

Tranny- The transmissions torque converter will not lock up.  1-2 mpg hit on the highway.  You can drive fine without it (a few people say this tanked their tranny, but I doubt this was the reason (read: abuse)).  Even if you want to hook it up, you dont need to get an aftermarket kit.  You can just wire up a switch on the dash to lock and unlock it using the diagnostics connection.

Coolant- You'll need a new radiator fluid neck.  The stock one doesnt work. (different orientation)

Summit Part #'s for needed parts!
HLY-20-95 (15$) Needed bracket for Holley + 700r4
HLY-20-37 (6$)
HLY-20-38 (5$)
These are the studs you'll need.  You only need two of these, but I forget which one I didn't need.  Better to have an extra stud than wait 2+ days to get your car running.
This is the quick change secondary kit and springs.  You NEED these if you have vaccum secondarys.
HLY-36-181 This is a jet assortment.  This is the most cost effective way of doing things.
ARP-100-9904 This is liquid thread sealer.  Reccomended instead of tape.
These are ARP carb studs and intake manifold bolts (6-pt).  They are stainless steel.
FPP-1256 The Fel-Pro intake manifold gasket set.
SUM-239433 Summit 14x3 drop base air cleaner with k&n style filter.  (with all of the [k&n filter + exhaust tip = top fuel] dragster rice burners running around, I do my best to not purchase their products.)
MRG-3704 Mr Gasket vaccum cap assortment.  You'll need a bunch of these.
Summit dual return springs and bracket, all chrome.

How To:

Keep you area clean!  Make sure nothing gets near the intake manifold or the runners.  Do not let anything near ANY holes.  Vaccum the tpi manifold twice before you pop it off, and inspect it carefully!

Getting the TPI off is quite a challenge.  The top is fine, but the runners are difficult.  There are bolts on both side of either runner.  Look hard!  This is not easy, but it can be done by even a novice mechanic, just take breaks and look hard.  (and you will be bending over the engine bay way too long, and your back will probably be sore.)

Don't plan on doing this in a weekend unless you are experienced, or you're going to be working into the night.  But that doesn't even factor in the time it'll take to get everything dialed in and working right.

1.  Start by getting together some soda, a lawn chair and some magazines, for the break's you'll need to take.  Second, round up all your tools.  The only special tool you'll need for removal is a torx bit.  You only need one, a T-45 (as I remember it).  A 2 inch extension is all that needed.  Third, get a plastic garbage bag and lay it over that big flat spot between the cars nose and the engine.  You will be setting a lot of tools/parts there, and many of them will fill into the numerous holes.  Unless you have stick arms, getting them out is a pain.  Fifth, get a large box to throw all of your removed parts into.  Sixth, be sure you have at least a half tank of gas.  If you have fuel problems, and need to do alot of testing, you'll be glad you did.  Seventh, drain your coolant!  I didn't, and I was sorry.  It'll get all over your garage, and intake manifold, among other things.  Also, removing your hood is optional.  I'd remove your hood if you have a bad back or short temper, but you don't need to.
2.  Remove the air intake system.  Most of the stuff is clamped together, and comes off easily.  The air intake can is held in by one bolt at the bottom of the can.  The MAF is attached to the bracket.  Take off the two radiator fan mount bolts, pull off maf, and reattach bolts.  Dissconnect the cables from the throttle body.  Some are held on by little clips.  Do NOT Damage these, and Do Not lose them!  You need them later.  You will also need to pull the cables out of the bracket  attached to the plenum.  The trottle body has some vaccum lines as well as two coolant lines going coming out of it that you'll need to remove.  The TB itself is attached by four bolts and comes off easily.

3.  Remove plenum.  There are a few vaccum lines, as well as a sensor or two.  5 or 6 bolts to a side, no problem.

4.  Note the green liquid at the front of the manifold.  Guess who didn't drain their coolant?  Getting these off was a pain.  Just hunt for and remove any bolts.  Most of the bolts are on the 'outside.'  The clearance is tight, and some are hardly visible.  The more difficult ones are the inside ones.  Some of these are partially/mostly obstructed by the fuel rails.  You'll probably have to loosen the rail bolts to get at them.  To get the fuel rails off, there are only 4 bolts holding them on, then it comes out as an assembly.  You'll also need to disconnect the two fuel lines at the front of the manifold.  Also, dissconnect the plug wires, remove the clamp, and pop out the distributor.  (due to it being computer advance, it is difficult to tell which gear the new distrib should be on.  I'll tell howto)

5.  By now, all of the intake to head bolts should be visible and accessable.  Before you go and pop the manifold off though, double check for any shit along the manifold (bolts, clips, screws, etc).  Vaccum off the edges.  When you take the manifold off, plug up the holes such as is shown if your going anywere or taking your time.  You'll need to scrape any crap off of the mounting spots, like RTV or other sealant.  I also took the opportunity to scoop out the sludge that had shown up in my lifter valley.  You can also check for pushrod play to see if the loud music you blast was covering up some valvetrain noise.

6.  Now you'll want to test fit your manifold.  On mine, I had to grind some of the flange off on the spots the orange arrows are pointing to.  There was a ridge on my heads that theseedges hit so the manifold wouldn't sit right.  With the gaskets in, this might not have been a problem, but it may have created a leak so why not?  If you were overconfident like me and got an 86 down manifold, you'll also have to grind up the bolt holes in the spots indicated by the dashes.  You should also take this opportunity to mount your hardware.  Here you can see why you need a new radiator neck.  If you used the stock one (does it even fit?), the opening would be pointing towards you.  Put on your carb studs.  The heater hose outlet was new, the old one was stuck in the tpi manifold.  You can also plug the other hole.  Neither of the sensors on the tpi manifold effect your dash coolant guage.  At the back of the manifold runners, you can see a plug.  I ended getting a 5/8 90 degree male treads to male nipple fuel line fitting by Spectre at my local Checker.  You'll need this to attach your power brake vaccum hose.

7.  Now is the time to bold your manifold on.  First, double check and be sure that your mounting surfaces are clean.  VERY clean.  Next, set the head gaskets in place.  I used some weatherstripping adhesive, which was reccomended in some SBC books.  There is also a gasket sealer designed for this, and I would have used that, were it not for the sheer and utterly complete incompitence of my local Weaver autoparts store, which apparanly cannot afford even second rate help (I've had several bad experiences there).  For the valley gaskets, you can use RTV or the gaskets you set came with.  Apparantly these edges are problematic, and cork gaskets seem to pop off, but my Fel-Pro ones had a good adhesive on the engine side, so I figured it'd be fine.  You can also see the worthless pain in the ass mallory regulator up front.  If you decided to get and use this regulator, have your neerest buddy give you a good smack for me.  Finger tighten the mounting bolts, and then slowly increase torque to each bolt in a spiral fasion.  Apparantly, aluminum manifolds especially are prone to warping if the torque isnt gradually applied evenly. 

8.  Now you get to install your distributor.  Pop out the number one spark plug, and have someone stick their finger in the hole.  Get a wrench on the crankshaft pully, and turn it CLOCKWISE till your buddy feels good pressure on his finger.  Turn the crankshaft a bit more untill the pully grove lines up with the 8 degrees notch on the timing indicator.  Now try and install your distributor.  Disconnect and remove the cap.  The wires that come out of the base point directly forward, with the vaccum advance can off to the left.  However, you'll need to turn the rotor around some.  Because of the angle cut on the gears, it needs to rotate a bit before it gets to the bottom.  When this thing is in, you want the rotor to be pointing towards the #1 cylinder firing post.  This would be facing forward, slightly to the right of the vehicle axis.  One problem may be the oil pump driveshaft.  This needs to hook into the bottom of the distributor.  If the distributor isnt perfectly flat on the manifold, and pressed tight and gapless to it, this is probably where your problem is.  To move around the driveshaft, you'll need a long flatheaded screwdriver.  To use it, close your garage door, or at least make sure no one is looking.  You'll need to 'mount' the engine bay with flashlight and screwdriver in hand.  Shine the light down while you rotate the shaft.  You'll need to do a bunch of this till you end up with oil pump engagement as well as pointing to the #1 cylinder firing spot.

9.  Put on your carb gasket, then the carb.  Tighten down the bolts in a star pattern also.  Be sure to add the cable bracket and return spring bracket before you tightend down the rear drivers side one.  Now you can see why the specific holley bracket was necessary.  Also not the dual return spring and position.  I changed it to red and orange because this was such a crappy pic, and the mounting was particularly creative.  I couldn't get the sucker to mount any other way!  You can see the bow on the throttle cable.  This is because the plastic doesn't hold it evenly in the bracket.  Holley needs to tighten up the tolerences.  Well, it seems real tight anyway, and I havent had any problems.  I doubt chafing would be an issue, either.  You can also see the skewed choke.  Be sure to adjust that if you have an electric one.  And redo your TV cable.  You do this by pusing the button on the side in, and pushing the plastic that sticks out all the way in.  Then, relese the button, and max out the throttle bracket travel.  You will feel/hear a 'snap', and part of the plastic will re-extend itself.  This is when your done.  Drive around for a bit, then re-adjust it.

10.  I'll add a section on the fuel system when i get the right setup in.  You can see that the stock radiator hose 'technically' fits, but not really.  I got a hose for an 84 t/a with ac and cut a bit off.  that fits fine, but it doesn't run through the stock location.  This is bad because the radiator mount and alternator still are designed to hold the stocker.  I'll list the part number when I find a well fitting one.  You'll also need to cut apart the manifold to hose coolant lines.  I inserted and clamped down a peice of brass pipe to connect them.

11.  Other notes:  You'll need to rewire your primary fan if you have dual fans, otherwise it wont come on.  You can also start hacking out the emissions system.  With the removal of those metal tubes that come off the exhaust manifold, I can now get all front six spark pugs out from the top.  It also looks better without that black box crowding the engine bay.  Make sure you take care of any vaccum lines.  Attach the distributor to ported vaccum (passenger side of primary metering block), attach pcv to fat port at back of carb, and plug power brakes into the manifold port mentioned in #6.


and why would the distributor get chewed up? Hardness of metals. I believe that newer roller camshafts are made of a harder metal, so an old style softer metal distributor gear would get chewed up. Gears can be swapped, but its not something I'd want to do.

I would be only changeing the intake manifold right? Manifold, distributor, carburator, fuel pump, and wiring modification (small)

What do I need to change over?

also.... im no expert mechanic but im a quick learner, whats a roller camshaft, and what does it have to do with the distrubutor? Attached to the back of the camshaft is a gear. This is what the distributor gear hooks into, and what turns it. A 'roller camshaft' is a cam used with roller lifters. Old camshafts bumped into and pushed up a lifter with a flat metal base. Roller lifters have a little wheel that hits the camshaft, so it reduces friction and allows more rapid lift (among other things)

if i do switch from tpi to carburated, will my cool gta features still work? like A/C, cruise control power brake booster, any and all sensors?(like oil pressure meter, battery meter, dummy lights?) The only thing that wont work is cruise control, because I havent seen a bracket yet that allows you to mount a tranny, throttle, and cruise cable to a carb. Everything else will work, provided you hook it back up. The info display will even work. Note: most older cars had the coolant temp sensor on the manifold. My car had two sensors on the manifold, but neither of them attached to the coolant readout. You don't need to swap these! You will need to rewire your primary fan, though. (assuming you have dual electric fans. only the second one is non-ecm activated).