Author Topic: 350 tbi build recipe  (Read 4796 times)

Offline 90_suburban

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350 tbi build recipe
« on: October 12, 2018, 08:01:35 PM »
I’m wanting to rebuild a tbi 350 I have and wanting somewhere around 300-320ish hp. Can anyone recommend a good cam and heads?  I have done some reading over at tbichips.com I know I will need to get the throttle body bored and a custom chip as well.

This will all be going in a 2500 suburban with one tons and 35” tires 700r4 and eventually double transfer cases. I also plan on doing some towing with it as well and would like something easily reliable.

I’m not sure if my best bet would be a vortec for the heads or rebuild the 350 I have install some kind of roller cam and some better aluminum heads or not. Just seeing what others think about it.


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Offline Irish_Alley

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Re: 350 tbi build recipe
« Reply #1 on: October 12, 2018, 09:47:47 PM »
im going to tell you the truth i would trust what he talks about on tbichips.com, but how long do you think the 700 will hold up?
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Offline 90_suburban

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Re: 350 tbi build recipe
« Reply #2 on: October 13, 2018, 07:09:21 AM »
im going to tell you the truth i would trust what he talks about on tbichips.com, but how long do you think the 700 will hold up?


Not sure how long it will hold stock. Right now it’s the 2wd suburban I just had the issues with. I will eventually get it rebuilt and switched to 4wd. Before having it rebuilt I will ask the transmission shop I use which is the best around. I’m pretty sure they can easily build it up no problem.

I’ll do some more reading over at tbichips.com and if I still don’t know for sure email him and get it recommendation.


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Offline 90_suburban

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Re: 350 tbi build recipe
« Reply #3 on: October 13, 2018, 07:13:17 AM »
If the transmission shop doesn’t think the 700 will hold up I will probably look at swapping the 4l80 and 91 computer into it.


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Offline VileZambonie

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Re: 350 tbi build recipe
« Reply #4 on: October 13, 2018, 07:19:20 AM »
Are you talking factory TBI system or aftermarket?
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Offline 90_suburban

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Re: 350 tbi build recipe
« Reply #5 on: October 13, 2018, 07:20:51 AM »
Are you talking factory TBI system or aftermarket?


Factory with the upgraded fuel pump and probably bored throttle body and upgraded fuel pressure spring. According to tbichips the factory tbi can handle over 300 with the mods and chip.


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Offline 90_suburban

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Re: 350 tbi build recipe
« Reply #6 on: October 13, 2018, 07:41:45 AM »
Nothing’s set in stone yet. Originally I was planning on doing a 5.3 or 6.0 but I think I can do the 350 for a little cheaper or the same and have a rebuild motor vs a used one.


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Offline Irish_Alley

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Re: 350 tbi build recipe
« Reply #7 on: October 13, 2018, 11:16:12 AM »
maybe just modding the tbi will be cheaper now but then when it comes to a trans rebuild you might be better off with the ls swap. but im not sure how much they run for
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Offline 90_suburban

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Re: 350 tbi build recipe
« Reply #8 on: October 13, 2018, 11:58:01 AM »
Might be. I’m still kinda weighing my options at the moment. I do know the 4l80 will hold up vs the 700 and the 4l80 can be had relatively cheap and will work with the tbi being they can in 91 up trucks


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Offline VileZambonie

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Re: 350 tbi build recipe
« Reply #9 on: October 14, 2018, 08:19:36 AM »
4L80E, they didn't make a 4L80. The 700R4/4L60 is fine for your setup if properly rebuilt but you can find a factory setup with the 5.7L/4L80E combo. Match the cam and the chip to your setup, shorty headers, aluminum tbi manifold and you'll have plenty there for a driver. Why the doubler though? Is this going to be an off-roader?
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Offline 90_suburban

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Re: 350 tbi build recipe
« Reply #10 on: October 14, 2018, 05:11:49 PM »
Yeah 4l80e is what I meant. Either trans would be fine with me. I was considering the 700r4 being I already have it. I’m wanting the doublers for dual 4 lows I don’t plan to take it off-road hardcore but would be taking it off-road some once I put the one tons under then I’ll be running 35s on it.

I was doing some more reading on tbichips I am thinking either finding a vortec rebuilding it putting a decent cam with aftermarket intake for the tbi with the chip and exhaust. Or possibly pulling one of the tbi 350s I have and finding a set of vortec heads and doing a 383 stroker and pretty much the same as above.

I will mainly be using it as a daily driver which my commute is very short I drive more on the weekends than during the work week. Other than that I will be using it to tow my camper (around 7000lbs) and tow my Jeep to the trails (probably 7500lbs with the trailer).


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Offline 90_suburban

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Re: 350 tbi build recipe
« Reply #11 on: October 14, 2018, 05:28:55 PM »
I’ve thought about just doing a 12v swap but I’ve done a diesel swap before and not sure I want to go through it again. I just don’t think I would gain as much from it.


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Offline Irish_Alley

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Re: 350 tbi build recipe
« Reply #12 on: October 15, 2018, 11:26:04 AM »
a few things, the doubler if youre not rock crawling is going to be a waist of money. the the 4l80e you need an electric speed sensor for the TCU to shift the trans so you cant just grab a 205 and make it work but you can buy a signal converter to make it work. the 4l80e and 205 only came in one year so finding a stock adapter is going to be really hard you probably have to buy one.

i did a 12v in my 91 v3500 (350 4l80e/205. i went from 12 mpgs to 16, theres a couple ways to do it. i pushed my trans back 3" made a new rear driveshaft and used GM motor mounts. if i had to do it again i would buy a cross-member made for our trucks and the cummins or make it. think they were around 400 but no need to push the trans back, cut into the firewall and make new driveshafts. besides and making the trans work there really wasnt much to it.
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When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline 90_suburban

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Re: 350 tbi build recipe
« Reply #13 on: October 15, 2018, 01:57:32 PM »
Your probably right on the doubler. I was actually thinking about doubling 2 241s or possibly a 241/300 but I may just stick with just a 241 transfer case. I was thinking about those transfer cases being I already have a 241d 231j and several Dana 300s. I also have the stock 208 from behind the th400 in the v2500 I have but I don’t like the slip yoke eliminator they make for it.

I’ve done one diesel swap in my Jeep with the 4bt just don’t think I really want to do another one. Not that it was too hard just think the built 350 would be a better choice being most of my driving will just be as a daily.

Definitely like all the different inputs I’m receiving I like overthinking things a lot


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Offline VileZambonie

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Re: 350 tbi build recipe
« Reply #14 on: October 15, 2018, 02:37:54 PM »
You need to rationalize what you want to do within your end goals so I would agree, some overthinking. If this truck is going to be mostly street, drivability is a concern and the main reason you want to stay TBI is the convenience & you will be towing your trailer occasionally, then focus on that. The doubler the 12V, etc just adds more to the mix. You should devise a plan and build to suit.
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