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400 small block ....powered with TBI??

This is a discussion on 400 small block ....powered with TBI?? within the Engine Swaps forums, part of the Projects and Builds category; Anyone done it? I know the actual engine will go obviously but can I power it with my factory TBI ...

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    Registered User bodean's Avatar
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    400 small block ....powered with TBI??


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    Anyone done it? I know the actual engine will go obviously but can I power it with my factory TBI with a few mods? I want to keep my factory look and reliablity. I have access to a 400 out of a 72 Caprice that has never been opened and ran fine when removed. That rebuilt short block with a mild cam and some ported Vortec heads would be a pretty potent match.

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    Re: 400 small block ....powered with TBI??

    I have an old '79 Chev with a 400SB in it. Great motor. I think you could TBI it if you had the skills. Same motor basically except some modifications to it as well. Idk if you take the TBI injection setup and put it on a 400 and tune it I'm sure you could get it to work.

    I'd say you'd need a bigger TB and injectors to harness all the power of a beastly 400 though

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    Re: 400 small block ....powered with TBI??

    I too may have acess to a 400 and have been pondering a TBI build with all the basic upgrades such as better heads, mild cam, Edelbrock TBI intake maifold, bored out TB, 9:1 CR, headers, etc. I hope more people respond to this with opinions and options. The only thing that I've found is to go to www.cfm-tech.com, (they specialize in TBI motors) and give them your specs, they claim they will be able to tell you whether or not they can make a program that will work with your motor, because I guess there are limitations to the TBI computer that will make it not work right with your build. I've never contacted them yet, but they seem knowledgable and friendly on their site, so I'd recommend checking it out, they have some good info on there that makes sense, you just have to search around on there a little. Good luck, and keep us posted.

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    Re: 400 small block ....powered with TBI??

    Anybody there???

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    Re: 400 small block ....powered with TBI??

    Yes this is possible. In order to run vortec heads you will need a different manifold edelbrock makes one. You will also need to have your computer reprogrammed. You may also need to bore out your throttle body and get bigger injectors a lot of the builds end up using 454 throttle body and injectors. check out tbichips.com they do custom chips for your computer and they have built a 412 (which is a .060 over 400) that is running tbi.

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    Re: 400 small block ....powered with TBI??

    I know yall are talk about the factory 400 sb is that about the same as a 350 punched out to a 400. I'm trying to make a really good sleeper.

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    Re: 400 small block ....powered with TBI??

    One of these days I'm gunna take my old '77 Chev 350 apart and my old '79 Chev 400SB out and measure the differences in the block.. I think bore plays a big dif tho

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    Re: 400 small block ....powered with TBI??

    If you want to go cheaper(with vortec heads) do a carb intake with TB adapter plate. As airgeirb said you could always get a 454 TB and injectors. IIRC the 350 one flows 480cfm..with ultimate tbi mods i think 520 cfm max. With an older motor it should have a 2 piece rear main seal whereas the TBI/Vortecs have a 1 piece. I dunno what you would have to do about that. Depending on whether your truck is an 88-92 or 93+ will decide the trans. 88-92 you can always build a 700r4 or put in a th350/400. 93+ you can build a 4l60e or swap to a 4l80e since you will need a tune anyway. If you have a 4/5 speed itll bolt right up. I know a member on here who ran an 8.1/nv3500 5 speed combo for a while so itll hold up unless you get ridiculous with the power.
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    Re: 400 small block ....powered with TBI??

    Not sure about running Vortec heads on the SB 400. The SB 400 uses a siamese bore block and the coolant holes between the block and head are located differently than the 350 block. FYI - the 400 is a 4 1/8" bore with a 3.75" stroke. 350 is 4" bore X 3.5" stroke IIRC. Regardless you're going to need some custom tuning.

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    Re: 400 small block ....powered with TBI??

    From what I understand, all you have to do is have a machine shop drill steam holes in a set of 350 heads and they'll work. A lot of aftermarket companies advertise that as an option so you can run their heads on 400's.

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    Re: 400 small block ....powered with TBI??

    Ok, lets do some responding and put up some deatails to try and keep this going. You can't punch a stock 350 out to 400, unless you buy a bowtie block and blah blah blah. 400's are becoming rare because they didn't make as many of them and a lot of dirt trackers liked to "destroke" them down to 377's (400 w/350 crank), also they tend to wear the bores oblong to the point that that they can't be bored out enough to make them round again. Yes 400's look the same on the outside as a 350, but do have many differences, the main one being that it is a totally different block with, as svwayne said, siamesed bores, and external balancing, etc. Although it does still have the same external dimentions as a 350 and will accept pretty much all the same bolt-ons, and fit anywhere a 350 fit. There really weren't any high performance 400's, it was mainly a truck and big car motor built for low end torque, but from what I understand with the right mods (none even that extreme) it can be made into a badass motor. 400's tended to have overheating issues and head cracking due to the siamesed cylinders and heads with steam holes, but I think that with better engine managment, a good cooling system, and some aluminum heads (for better heat dissipation) you could have a decent and powerful daily driver. This is just a quick rant to try and spur this thread up a little, a lot of details were left out, but I hope this helps keep it going.

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    Re: 400 small block ....powered with TBI??

    Quote Originally Posted by 95-Cheyenne View Post
    400's tended to have overheating issues and head cracking due to idiots slapping on a different set of heads and not drilling the heads with the necessary steam holes or lack of cooling system maint. led to the steam holes clogging with rust
    Fixed. I never had issues with overheating and abused one for 10 years. It was stock except for the cam, intake, and carb

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    Re: 400 small block ....powered with TBI??

    I am definatly considering a swap to a 407 or a 412 ( I have two differant cranks - one is 3.812 stroke) and pull my 454. I'll re-use the tb and it's adapter - on top of an RPM (non air-gap) intake, and would convert the block to a factory roller cam setup.

    If I were you I'd use at least a stock size 454 tb, or a bored 454 tb. The bigblocks came from the factory with a nice tb to carb intake adapter. You won't be able to make a tb too big for anything 350ci and up.

    I may use the '93 350 tbi swirlport heads since I'll have a whole parts engine soon and am really just after torque and mileage vs HP. Vortec heads may be irresistable if they end-up within budget. Should have tremendous throttle response and torque - both rivaling a 454's.
    My swap will hopefully come later this year before 4wd season returns again.

    I'm up for you hitting your goal and then telling us how great it runs ! GO FOR IT.

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    Re: 400 small block ....powered with TBI??

    Also check out cfm-tech.com, they have alot of info on the TB's. They sale ported TB's that for the 350 will take it from 480 cfm to 620 cfm or you can buy their 454 TB's and from factory they flow 640 cfm and their ported ones are 720 cfm. They also have rebuilt injectors that are flow tested to be within 1% of each other, the factory's have tested up to 15% difference. all info is according to the website. I would check it out lots of good info on their site.

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    Re: 400 small block ....powered with TBI??

    @rusted_shut, I couldn't agree more with you, I was just posting some quick generalizations to get some people to chime in and I guess it kinda worked. The kind of feedback you gave is what I was looking for. Now people will realize how important the steam holes are and cooling system maintenance if they decide on a swap. Thanks.

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    Re: 400 small block ....powered with TBI??

    I have a 76 400sbc in my 88 and i put the 88 vortec heads on it the stock 350 vortec intake and tbi system and mine runs just fine the motor is also has a mild cam in it. It will bump your compression to about an 11:1 so you will have to run higher octane fuel in it but its well worth it if you ask me.

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    Re: 400 small block ....powered with TBI??

    Do it.

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    Re: 400 small block ....powered with TBI??

    Quote Originally Posted by chevy882500 View Post
    I have a 76 400sbc in my 88 and i put the 88 vortec heads on it the stock 350 vortec intake and tbi system and mine runs just fine the motor is also has a mild cam in it. It will bump your compression to about an 11:1 so you will have to run higher octane fuel in it but its well worth it if you ask me.
    Those are not Vortec heads, nor a Vortec intake. They are TBI heads and intake. Vortec came out in '96.
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    Re: 400 small block ....powered with TBI??

    no they are vortec heads they put vortec motors in the eighty eights on it comes stock with a vortec 350 motor you can ask any local parts store one very simple way to tell if they are vortec heads is to look at the valve covers all vortec motors have the bolts in the center of the valve cover like mine do.

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    Re: 400 small block ....powered with TBI??

    You depend on parts store people for advice? LMFAO. Vortec came out in 1996. TBI centerbolt valve covers are not Vortecs. Vortec has a whole 'nother intake system also, and OBDII. TBI is OBDI.
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