Need some advice on injection

[bigbadchev84]

I have a 67 chevy 4x4 longbed truck, 3.73s 6" lift and 35s. I have a fairly built 400sbc,th400/208 in it. I have yet to really drive it since it is torn apart for bodywork, But as soon as it is done I will be selling my 05 tacoma and start driving this as my dd. i feel alot more at home in old iron, plus the no monthly payments thing will be an added bonous.

i will be getting a aftermarket a/c system for it and was kicking around throwing some sort of fuel injection on it. would I be better off with a stock tbi, or maybe an aftermarket injection kit? Not really conccerned about the price as long as it dosent go over $3000.

Will I honestly notice a decent mileage increase on average over a carb? I really just need reliability, but I dont really want to go into cam changes and whatnot since the motor runs flawless as it is. Maybe i should just leave well enough alone?

 

[dave w]

Will I honestly notice a decent mileage increase on average over a carb?

Yes, a good tuned EFI system will increase mileage over a carburetor.

I really just need reliability, but I dont really want to go into cam changes and whatnot since the motor runs flawless as it is. Maybe i should just leave well enough alone?

Depending on the camshaft in the SBC 400, tuning an EFI system could be a real challenge for a beginner EFI tuner.

If you want to learn EFI tuning, converting the SBC 400 to EFI would be a good way learn. The SBC 350 is a more common engine, so tuning an older SBC 350 for EFI is better supported. Retro-fitting a factory SBC 350 EFI system onto an older SBC 350 is easier, because 99% of the EFI tuning is already done. Usually deleting the Emissions programming from a Factory 350 EFI system for an older SBC 350 is all that is needed when retro-fitting an older SBC 350 to EFI. To tune a SBC 400 using either a SBC 350 or BBC 454 Factory EFI system for the SBC 400 will require changing the fuel settings, and if using a 454 EFI system on the SBC 400 the timing settings will require changes.

I think a good option for a beginner EFI tuner who is REALLY motivated to learn, is start with the Dynamic EFI system http://www.dynamicefi.com/ The Dynamic EFI system looks expensive, but the Dynamic EFI system does not need PROM burning equipment and the EFI tuning software included.

The only reason why I don't use Dynamic EFI is because I like going to my local parts store to get EFI parts. NAPA Auto Parts stores does not have a Dynamic EFI computer sitting on the shelf.

dave w

 

[jolane]

I can giev you my experience with EFI. I have a Holley 4 barrel TBI system with the commander 950 computer. It's MUCH better than a carb in many ways. It starts up and idles well, it runs on inclines SIGNIFICANTLY better, and it gets much better mileage. I went from 9-10 MPG average to 14+. Those are honest hand calc numbers. This is on my 86 Burb with 1ton's, ~5-6 in lift, 35" BFG AT's. Note that I'm using a wideband O2 sensor...which really helps tuning and fuel mileage. Definitely worth it!

Now, the honest part. It was not a one conversion. It took a while to learn how to install and tune. I'm using computer controlled timing too. That is excellent to have! It takes some patience. I got a lot of help from some guys over at Chevytalk.com. They have an EFI section with a number of people running the C950. It's a good system at a fair price. Would I do it again...yes...but I'd use port EFI off the bat. It costs more, but it should get better mileage and be easier to tune. Sometimes I think my engine is too small (stock '86 350 SBC with headers), and I think the TBI might be a bit too big for it. The port would handle the low fueling requirements better I think.

Since I've gotten it running well I haven't messed with it. Seemed like I was always messing with the carb...changing weather, ran poorly when I'd go to altitude to hunt (from 5K to over 10K), etc. For a daily driver, definitely look into EFI. I looked at using a stock TBI set-up, but by the time I put the system together and paid for chips (that may or not be the best combination), I figured why not just go all the way. Plus, I also got WBO2...a great thing!

Good luck!
Joshua

 

[GMC Truck]

The F.A.S.T. EzEFI could be an option for you. I looked into this system for my 83 chevy 3/4 DD but it was a bit above my price range ($1800-$2200). I went with a stock GM setup pulled from a running 89 burban and used a plate to mount the TBI unit on my stock manifold. After learning to tune the system (with alot of help from this site) it runs and performs great, but my enging is a almost stock 350 and that makes the "starting" tune easier. The FAST EzEFI system is for modified engines and looks really easy to setup and it will tune itself to match your engine.
I'm currently looking for another EFI system for the truck pictured below, its a 1986 GMC 3/4 ton with a 357 and a SM465 4 speed. Frameoff restored and a trophy winner. I dont know if I want to go with stock GM stuff on this or try the EzEFI on this cause it had a modified engine??