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TPI on a 73 350

Discussion in 'TBI & EFI Conversions' started by custodian, Feb 25, 2017.

  1. custodian

    custodian Full Access Member

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    I'm looking to put a TPI system on my 73. It's not stock by no means. The system came off of a 87 Camaro. I know the heads are different. Any thoughts?

    I tried to search this site but couldn't find what I was looking for.
     
  2. 1987 GMC Jimmy

    1987 GMC Jimmy Automobile Hoarder

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    I think it's cool as hell, but the swap is much more feasible going from a TBI square to a TPI instead of a carb to TPI. There is stuff you have to do first. The four center intake holes need to be ground on angularly to bolt up to older style SBC heads. I'm guessing this is a MAF system so I'm also guessing you can bypass a VSS input without affecting anything since your cluster wouldn't have a VSS buffer behind it, right? Not sure on a '73 square. You need a bung in your manifolds/headers for your O2 sensor. If you're running headers, you'll need an extra 12V wire going to a heated oxygen sensor. And you've gotta figure out your fuel delivery situation and block off where your mechanical pump is now. The best, most tidy way would be to run 1987 square body tank(s) with a TPI intank fuel pump, but if you're running duals, the pressure is gonna kill the switch valve so you'd either have to do what the LS guys are doing to run duals or switch to a single, 25 or 31 gallon tank. There are external pumps out there, but I've personally never liked anything like that. You said it was modified. Is that your truck or the TPI setup? The MAF system is more forgiving on engine mods than the speed density system is, but you have to run a computer friendly cam. Not saying the cam's gonna suck, but you can't run a nasty, lopey cam. Speaking of computer, you have that and the wiring harness right? It's best to get everything from one car because you have differences over the few years TPI was produced. I might be missing something. Hmm, your '73 cluster won't have an SES light in it. I wonder how different a later square cluster with an SES light, a mechanical speedo, and a for sure compatible VSS buffer in back is compared to what you have now in terms of the printed circuit and the connector that plugs into it. It's a lot to think about.
     
  3. Green79Scottsdale

    Green79Scottsdale Full Access Member

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    I have a TPI intake I am going to try to gey on my 400 this year. I just love how they look!

    The whole head/intake issue isn't that bad. You have three options. Grind and clearance your late -intake to match your early heads. Get later heads to match the intake. Or get a Corvette/85-86 F-body lower intake. All year Corvettes got the standard 90* bolts, as did the first couple of years of F-bodies.

    Other than that, as said above, it is really a matter of giving the computer the info it needs from the different sensors and such.

    I am looking to run a Megasquirt system on mine for controls. I have found that stock computers and wiring harnesses are getting up there in price, very close to what you would spend on a Megasquirt. With the stock stuff you run into the need to burn chips, whereas the Megasquirt is all computer based. And if you ever want to switch to a LS motor, the Megasquirt can control that too!

    Good luck!
     
  4. Rusty Nail

    Rusty Nail Whatever!

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    You can't find what you're looking for on THIS SITE because it doesn't exist.
    The TPI swap us a RAAAARRRREEEE bird.
    That said, nobody here has the answers you want. I think there are three of us, we'll have to stick together and pick on Jerry from time to time. ;)

    MAF is hands down the right choice, i'm prepared to spend $400 for the harness alone.
    '85 was the last year before VATS (computer chip in the key) Vehicle .Anti .Theft .System. My TPI is '86 and I have an '85 Corvette computer FOR THOSE REASONS and the harness is still gonna run $400. From what I gather, the stock harness will bring you down if you try to use it but you can recoup some cost selling it. All you really gotta do is install a few correct sensors and get power to 5 places? + turn the original key in the original cylinder. The complete swap is NOT hard, and you can make it really easy on yourself.

    Bottom line is it's NOT cheap but that kind of major-league badassery never is.




    Yes, badassery. :happy160: :boobs:
     
    Last edited: Feb 27, 2017
  5. custodian

    custodian Full Access Member

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    My motor is bored 40 over, Comp Cam, roller rocker arms, flat top pistons, Sportsman II heads, headers, 2 1/2" exhaust. It does have a rough idle. I don't plan on changing my heads.

    I have read that the TPI is not suited for rough idle, any thoughts?

    Still looking for the right setup. The unit I first looked at was really a piece of junk.
     
  6. Rusty Nail

    Rusty Nail Whatever!

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    I always doubt those types of naysayers have ANY first hand experience in what they speak of. Exactly like the don't run 305 heads on a 350 guys. You know the types....They have OBVIOUSLY never done that sooooooo they should STFU. Easy examples :there are videos on the youtubes of some pretty radical cars running TPI on the street or the track, and they don't seem to have any trouble!

    I don't consider stuff like that until it actually becomes issue. Likely stems from the computer trying to set idle speed? There are ways around anything brah! :) By the time you get that far into it, the solution will present itself or make itself solvable. Until then , you're wasting energy :imo: - no offense intended.
    Something about the dreaded ninth injector maybe? Later speed density systems are a lot more trouble. That's probably what it is.

    You asked for thoughts and that's them.

    About that.

    Right now.
     
    Last edited: Feb 27, 2017
  7. custodian

    custodian Full Access Member

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    Thanks, still going with the early TPI if I can find a good setup. Trying to read all the articles on the swap.

    My speedo will remain stock unless I set it up with new gauges. I'll just get the right setup and go from there.
     
  8. bluex

    bluex Full Access Member

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    I have a TPI setup I wanted to run to. I was going to modify a 96 L31 (vortec 350) harness and run it off a 411 computer. I even have most of the parts for it already. I've spoken with some local tuners and they are sorta iffy about tuning it for me. I'm not really feeling like it will be worth the hassle if I need to buy the stuff and do the tuning on my own. There is just to much cost and time in learning all that, not to mention if I accidentally grenade my engine. I have pretty much convinced myself to go with either a FiTech or Holley Sniper system instead....
     
  9. KnockingDiesel

    KnockingDiesel Member

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    My cousin, Bill, had a 88-90 1500 RCSB that was owned by a GM tech, who converted it to TPI in the early 90's. he bought the truck in 95 and had it until his brother in law wrecked it in 2001. truck had tons of low end torque and was pretty quick, best run was a 14.95 at 90 something mph. all the 454ss boys were shocked when they seen that 350 under the hood. I guess my point is that it was lots of fun and ran incredibly well, those TPI intakes make all their power below 4500 rpm, lots of fun stop light to stop light. Its pretty reliable over all, my 91 Z28 is a TPI.

    I would not recommend the factory style fuel injectors though, theres a place in Florida that converts ford injectors to fit the TPI rails. Also the the 87 may have the 9th injector (for cold weather starts) that is usually eliminated. If you run it in cold weather the throttle body should remain heated (they run coolant through them to keep them warm) but if you're in a warm climate then by pass the coolant through the throttle body. It makes a difference, try to touch a throttle body with out the coolant by pass on it, its as hot as the exhaust manifold.

    Sorry to be long winded but I like the TPI set and so rarely is it considered an option....
     
  10. Rusty Nail

    Rusty Nail Whatever!

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    Pics if the '91? Ima fan. Does it got that cool spoiler on it? NOT a fan of the 91-92 wheels even though I understand the 2 year draw. My banker wants me to buy another car, I am (lightly)looking for an IROC but don't really want to.
    If I open another loan, that's what I'd go for. :headbang:
    Sadly, it would take the perfect one. I always liked the blue ones! Did silver exist? I would pay a lot.
    Anyways, I digress... :)

    It makes sense. Absolutely perfect sense to TPI convert a TRUCK but the question is, why didn't the General ever do it? Not even in a limited edition or nothin? Everybody is always talking about torque builds and shit...TPI seems natural to me?

    Kinda like the General de-tuned the Zcar motors to not outshine the Corvette, I guess. They had taller gears and stuff... A TPI truck is TOO COOL and works TOO GOOD.
    Let's do it Brothers! :grd:
    The rest of you - enjoy the pleasures of conformity. ;) haha I joke, I joke, I keed! I keed!

    I actually STARTED my project today, and by "started my project" I mean = spring-cleaned out the garage and started looking for parts! :D
    Found two. :(

    Ya like Huey Lewis and the News?


    [yt]Ruw9fsh3PNY[/yt]
     

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    Last edited: Mar 1, 2017
  11. RetroC10Sport

    RetroC10Sport Super Moderator Staff Member

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    Sorry I missed this thread.
     

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  12. Rusty Nail

    Rusty Nail Whatever!

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    Rad. Is that yours?
     
  13. RetroC10Sport

    RetroC10Sport Super Moderator Staff Member

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    Sure is @Rusty Nail, built it over the past summer.
     
  14. RetroC10Sport

    RetroC10Sport Super Moderator Staff Member

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    But why run a Corvette harness? Camaro/Firebird is much cheaper and easier to adapt, plus VATS was first used in 1988 on the Firebird then 1989 on the Camaro. VATS can also be easily bypassed or removed by someone with a chip burner, a few people on here have them.
     
  15. Rusty Nail

    Rusty Nail Whatever!

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    You know more about it than me dude. My harness was worth good money to the guy that bought it and i didn't want it. Im not going to run a Corvette harness.
    Zero interest in bypassing anything... I'll get a brand new something just for me and my truck when the time comes.

    Painless is pretty high, like $500+ is unreasonable.
    http://www.painlessperformance.com/webcat/60102
    I'll prolly start here. They are smaller and i reckon theyll prolly try harder to do better at a more personal level. I want to support​ that at $380.
    http://www.fuelinjection.com/tpi/engharn_tpimainpage.htm

    I bought an 85 computer on purpose because that's what i want. If it doesn't work out then it wont work out. My understanding is that is desirable to me + the price was right.

    My TPI came from an 86 Corvette and I bought that on purpose because that's what I want. Perimeter valve cover heads are win and I have several. Itll most certainly be on my 400 one day after it runs again.

    Idk. Idc. And idgaf. Itll figure itself out and ill pay what it costs to get what I want. Saving a buck never entered my mind . /shrug
    I'm not trying to be a dick , but its just money.
     
    Last edited: Mar 15, 2017

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