TBI Conversion on a 400 SB w/4spd...
 

Hey Everybody,

I need a check list for converting my 1980 3/4 Chev 4X4 to a TBI setup.
It has a 400 SB with the 4spd manual. Which throttle body and ECM would I need for this?

Any advice on the swap would be good too.

Thanks in advance.

David

Re: TBI Conversion on a 400 SB w/4spd...
 

http://67-72chevytrucks.com/vboard/s...d.php?t=317519

That is a TBI swp thread. I converted my '74 to TBI recently, but haven't had a lot of time to test it out. I used the harness from www.fuelinjectionconnection.com and have been pleased. Robert was really good about answering all of my questions, even the dumb ones. I would tryo to get as much as possible off of a TBI 454 wherever you may be able to scrounge it (wrecker, pick a part, craigslist, etc). There is a lot of good info on www.binderplanet.com , they have a fuel injection board. I guess if you have an IH vehicle and you want to inject it, you have to be pretty crafty.

Re: TBI Conversion on a 400 SB w/4spd...
 

David

400CID falls between 454 and 350 stock calibrations. Look for 1227747 ECM and BBC TBI with 80 lb-hr injectors (as noted by JohnyBoy), but you'll need a custom EPROM. EPROM tuning will depend on your 400 build - keep in mind that stock TBI calibrations can not handle fire breathing monsters (low idle vacuum, long duration cam shaft is a big no-no). So go through the swap thread, make a list of questions and fire away.

//RF

Re: TBI Conversion on a 400 SB w/4spd...
 

RF is the man. He'll help get you lined out!

Re: TBI Conversion on a 400 SB w/4spd...
 

Try and find some Police car TBI injectors, They are 65Lbs per hour vs the 55 for the TBI 350 trucks,

Re: TBI Conversion on a 400 SB w/4spd...
 

Where on the injectors is the color coding?

Also, I have a 94' tbi set up that I was going to use, but what years are better?

Re: TBI Conversion on a 400 SB w/4spd...
 

I am sorry to say but above posting contain erroneous information.

Truck 5.7L TBI injectors at 13 PSI generally flow around 62 lb-hr. These injectors are color coded with Brown-black marking on the top ledge. It is better to id injector by a part number - search TBI thread for part numbers.

305 injectors (car or truck) flow around 55 lb-Hr and were marked with green-white markings. Again it is best to go with part numbers.


The famed 68 lb-Hr COP injectors are rare and expensive. Instead a simple increase in fuel pressure from 13 PSI to about 16 PSI with a standard 62 lb-hr injectors will provide additional fuel flow. This can be done by replacing OE FPR with adjustable from JET (61500) or eqv. TBI injectors can be run at 20 to 25 PSI to feed larger CID engines, but increasing FP may result in rich idle due to physical limit of how short injector pulse duration can be (1 mSec is an absolute minimum )

//RF

Re: TBI Conversion on a 400 SB w/4spd...
 

Just about any year TBI (87-95) can be used. The problem will be the PCM. Starting in 93 GM switched from C3 style ECM's (1227747 is a typical part number used in trucks) to a much more powerful and capable P4 - powertrain computer module (PCM). PCM can be identified by red/blue interface connectors and ECM used all black connectors.

P4 was advanced for its time, but can be modified to control larger displacement engine. It was also used with manual M4, non-electronic and electronically controlled automatics (700R4, 4L60E and 4L80E). The problem is a learning curve that you'll have to overcome to tune this PCM. There are online resources available (forums) that cover this PCM and its modification.

//RF

Re: TBI Conversion on a 400 SB w/4spd...
 

I forgot, Will it work fine with the stock cam or do I need to put a tbi cam in it? Also, the tbi intake has the same ports as the early chev sb engines, correct?

As for a speed sensor input, can I just use a 88 - 91 speedometer with the pickup on the back?

Thanks for the help....

Re: TBI Conversion on a 400 SB w/4spd...
 

The center ports on the TBI intake have a slightly different angle, but can be oblonged a bit with a drill bit. Not much of an issue. The TBI cam is pretty puny; as long as the cam in the engine now isn't huge, it should be fine, I would think.

On the trans, I used a VSS from JTR www.jagsthatrun.com and it screws to the transmission, and the speedo cable goes into the sender. It was $75, and will allow you to use your factory cluster with no issues.

Re: TBI Conversion on a 400 SB w/4spd...
 

I would look into megasquirt if I were you, you can run it fuel only, or ignitiion, use your stock speedo, and they work great with just a tbi body on an old modified intake.

Easily tuneable, can be repaired yourself, even built all yourself. May take a bit more learning on your part, but there is information all over the net, and you wont have to mess with the huge factory loom mess, and all the other associated junk.

http://www.diyautotune.com/tech_arti...part1-nova.htm

Re: TBI Conversion on a 400 SB w/4spd...
 

That's true. You could run a throttle body adapter to your existing intake. You will need a place to put your CTS, but that's not a huge deal. Check out the guys on binder planet. You have to be somewhat resourceful to run an IH engine anyhow, much less inject one.

Re: TBI Conversion on a 400 SB w/4spd...
 

Question:

Could I use PCM # 16197427 (BJLF) OR 16196395 (BJLH) to run the TBI conversion on my 400?

Thank you very much!

Re: TBI Conversion on a 400 SB w/4spd...
 

check out the TBI conversion thread. I bet RF has a lot better idea.

Re: TBI Conversion on a 400 SB w/4spd...
 

Without getting into a last detail a simple answer is YES. Either 7427 or 6395 PCM can be used to 'feed' 400 CID. However - you'll need to source 454 TBI (with 52mm bores) and a pair of 80 lb-hr injectors in place of 62 lb-Hr units used to feed 350 CID. A bump in fuel pressure from 9-13 PSI to 15 to 18 PSI will make injection spray better.

A change of BPW constant in EPROM should be a starting point.

A WBO together with data logging will take care of the VE tables. WBO is required to dial AE and PE tuning especially at WTO.

//RF

Re: TBI Conversion on a 400 SB w/4spd...
 

What are the part numbers for the cop injectors? The tb motor that I ran in my 71 for a while came out of a 9C1 box caprice. I still have the intake and tb, the long block disappeared some where. Jay

Re: TBI Conversion on a 400 SB w/4spd...
 

You do not need 'cop injectors' - they are hard to come buy and expensive to boot. The so called cop injectors (9C1) are rated 64 lb-Hr. Just use plain vanilla 5.7L truck injectors that rated at 61 to 62 lb-Hr. Get adjustable fuel pressure regulator from Jet performance (Part # 61500) and increase fuel pressure from 13 PSI to about 18 to 20 PSI. GM TBI injectors work just fine with increased fuel pressure - but you must incorporate fuel pressure gauge into your fuel feed line and make sure that your fuel pump is capable of at least 30 PSI. When all said and done you'll have to address these fuel system changes in EPROM.
When looking for a TBI compatible cam look for cam that does not have huge duration at 0.050 - 0.205 to 0.218 deg max with LSA not less than 112 deg. TBI system relies on MAP sensor to determine fueling and large overlap cam will make your idle a living nightmare.. Avoid wild cams - been there before - not fun!

//RF

Re: TBI Conversion on a 400 SB w/4spd...
 

I wonder if I could get away with the new Edelbrock Performer Plus Roller Cam.

It claims to have good vacuum, idle, etc.



The most that I though of doing was that cam or just a regular performer cam, MAYBE stock Vortec heads, headers, dual exhuast with a X pipe, a performer intake, high flow air intake.

Can I pull this off with TBI?

With using that I would asume that the 454 TB and the 80/90lbs/hr injectors are nessasary....

Re: TBI Conversion on a 400 SB w/4spd...
 

Ok, lets be a bit more specific:

Consider Edelbrock # 2103
ENGINE: CHEVY 400 V8
RPM RANGE: Idle-5500

Duration at 0.006" Lift: Intake: 288° Exhaust: 288°
Duration at 0.050" Lift: Intake: 214° Exhaust: 214°
Lift at Cam: Intake: 0.295" Exhaust: 0.295"
Lift at Valve: Intake: 0.442" Exhaust: 0.442"
Timing at 0.050" lift: Open Close
Intake: 0° ATDC 34° ABDC
Exhaust: 44° BBDC 10° BTDC
Centerlines: Lobe Separation - 112° Intake Centerline - 107°

This is a relatively mild streetable cam and should be ok in 400CID.

In my 383TBI I run 08-304-8 (266HR-14) camshaft

Cam Style Hydraulic roller tappet
RPM Range 1,400-5,400
Intake / Exhaust Duration at 050 inch Lift 210/220
Advertised Duration 266 int./276 exh.
Intake/Exhaust Valve Lift with 1.5:1 0.500/0.510 in.
Lobe Separation (LSA (degrees) 114
Computer-Controlled Compatible Yes

It (08-304-8) appears to be a very mild mannered cam shaft in 383. I have no trouble feeding it with BBC TB and pair of 80 lb-Hr injectors with VFPR. You can search youtube (RFmaster and TB) to see test engine video of that engine running. The reason for BBC TB is that 400 CID has big 'lungs' and above 4000 RPM SBC TB will be limiting amount of air entering into the intake. HP will drop of rapidly - similar to NASCAR racing restrictor plates that limit upper end power.
The reason for 80 lb-hr injectors is that for engine transients your 400 CID needs fuel, lots of it. An engine transient occurs during throttle tip in, or when there sudden increase in engine load. These events - dTps or dMap (delta TPS or delta MAP) provide engine with a 'pump' shot of fuel preventing a bog during acceleration. Smaller 62 lb-Hr can not deliver enough fuel, even if fuel pressure is increased. A short duration power event demands large amount of fuel which smaller injector simply can not deliver - not enough volume.

You can start with stock 5.7L TB and injectors, but you will quickly find the higher RPM power drop off and bog during moderate to hard acceleration.

//RF

Re: TBI Conversion on a 400 SB w/4spd...
 

I don't need any, I may have some already. I was curious about the numbers. I am running a ls in my 87 now. Jay

Re: TBI Conversion on a 400 SB w/4spd...
 

I ran a TBI 406 in a 9-0 GMC truck bout 10 years ago. The motor was .030 over, Keith Black pistons, 22cc dish IIRC, 5.7" rods. Real solid lower end. Heads were stock rebuilt 350 heads, had the steam holes drilled for a 400. The cam was a Comp Cams Extreme Energy 268, dunno the specs, but sounded SAWEEEEEET!!!!!! STOCK TBI, STOCK INTAKE, STOCK ECM, STOCK PROM, everything stock that came off the 350 that was replaced. I had headers on the truck already.

The truck ran like a raped ape. If the tranny wasn't on it's last legs would smoke the tires till the blew. I put about 10k on the truck before I sold it. I drove it around DC, and in Binghamton NY where I am now. 4 and 1/2 hours one way, doing 70 the whole time. I NEVER had any problems with this setup. Would sit there and idle all day long, never got hot, check engine light didn't even come on. After I sold it, the dip**** who bought it blew the motor up cause he was spinning the tires everywhere he went.

Re: TBI Conversion on a 400 SB w/4spd...
 

In retrospect you probably left 20 to 25% of performance on the table with a stock 350 EPROM. The 400 low end torque and long 5.7" rods contributed to low RPM performance <4000 RPM which is more than adequate for street application. The XE268 is a great choice for a flat tappet 350, 383, 400 CID engine. The 114 deg LSA keeps valve overlap to a minimum and results in smooth 16 to 18 in-Hg vacuum at idle which MAP sensor needs for idle mixture control. I would not put it into 305 - just a little bit too much of cam for my liking, but it is only my opinion.

Manufacturer's Part Number 12-268-4
Cam Style Hydraulic flat tappet
Basic Operating RPM Range 1,800-5,800
Duration at 050 inch Lift 224 int./230 exh.
Advertised Duration 268 int./280 exh.
Valve Lift with Factory Rocker Arm Ratio 0.479 int./0.480 exh.
Lobe Separation (degrees) 114
Computer-Controlled Compatible Yes
Grind Number CS XE268H-14

//RF