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TBI conversion

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RustyCruiser

New Member
I am interested in having someone install a stock TBI conversion on my 383, I am scared to death of the wiring, anyone have any contacts?
Thanks
 
jinxspot

jinxspot

~ Bush Eater's Offroad ~
Location
Salt Lake Utah
Call my buddy Jeff, he does everything top to bottom as a personal mechanic on all makes and models. He is a good wheeling buddy of mine so he knows offroad rigs and crawlers especially... tell him Ryan sent ya.

Jeff Smith in SLC
801-651-9618
 
H-K

H-K

INFIDEL
Supporting Member
Location
SLC UT, USA
I have TBI on my 383 and I used a harness from howellefi.com. Good stuff.

Side question: Is that 383 a high-performance engine? Mine is and I'm kinda regretting going with TBI because it's CFM limitations are holding the motor back. From what I read, even with the mods I did to the TBI unit, I'm missing out on about 30-40+hp and the modded TBI can only flow enough for a motor with ~290 hp. My motor was dynoed at 336hp using a Holley 750 carb.
 
H-K

H-K

INFIDEL
Supporting Member
Location
SLC UT, USA
I've been eyeballing that Holley unit. There are also some companies that bore out the GM TBI for you for about $300, but the flow gains are not as good as the Holley and only slightly better than the mods I did myself. Some have said that the injectors in those are "flaky" or "have problems", but I couldn't find anything more specific on what "flaky" meant or what problems they were, specifically. I'm still considering it. Only other thing that makes me hesitate getting that unit is that I'll always have to get replacement injectors, parts, gaskets from Holley and who knows how long they'll continue to carry that line. GM parts are plentiful anywhere you go. That said, it would be nice to let this engine breathe more and take advantage of that extra power. RustyCruiser, if you have any questions about my experience with TBI on a 383 and the mods I did, feel free to e-mail me at sbcjeep@gmail.com.
 
Chevycrew

Chevycrew

Well-Known Member
Location
WVC, UT
I don't remember really anything about it. But once I read something about using the 454 throttle body for 383 applications.

But it may be the same part # and injectors for all I know.
 
H-K

H-K

INFIDEL
Supporting Member
Location
SLC UT, USA
the 454 does use different injectors and there are differences in the TB. Using a 454 TB requires using the 454 computer and from what I understand is more difficult to get working with a SBC. I originally used 454 injectors in my 350 TB, but am now instead using 350 injectors with an 18-lb regulator spring to achieve the same-ish result. This was the recommendation of a professional engine tuning shop who tuned my ECM. The reasoning was that the 454 injectors are becoming hard to come by. Now my bottleneck is just in the amount of air that little TBI can pass. Since most of my offroad driving is in the lower-RPM range, I don't think it's a huge restriction, but I'd still like to be able to open it up and rev it higher.
 
DaveB

DaveB

Long Jeep Fan
Location
Holladay, Utah
I have a 454 TBI hanging around in the garage if you could use it. I put a 350 TBI on my commando with a 350 sbc. I used the factory harness from a chev truck and deleted what I didn't need.
 
broncomitch

broncomitch

dont be a sheep in a jeep
Location
west jordan,UT
I just did the TBI swap on the bronco...still working out a few bugs and need some new parts..

I went the cheap route and pined out a chev harness and such...it was really easy but I would go with the howell kit in a hart beat.
for $1700 you get all new parts, new wiring, new sensors,ect and life time free tunes.

its a really decent deal.

if your interested in trying it yourself ill send the link to a very specific TBI conversion thread I found.
 
H-K

H-K

INFIDEL
Supporting Member
Location
SLC UT, USA
I had originally started with an oem GM harness and about three hours into it, I decided the $300 for a pre-built, labelled harness from Howell EFI was a bargain. The instructions that come with it step you through each connection and don't leave you scratching your head wondering if you're doing it right. The complete kits may *seem* pricey, but are totally worth it. I did the complete kit on my 4.2 YJ engine (the one I had before I dropped a 383 in) and it covered everything -- no extra trips to parts stores, junkyards, etc.

Also, check out this page on mods for the TB unit. I did all of the mods and supposedly get between 490-500 CFM. Not quite enough for my application, but on a milder V8, it might be perfect. http://tbichips.com/?page_id=217
 
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