Switching from stock 305 TBI to mid-mild 350, TBI or Aftermarket EFI?

[RichLo]

I have a mid to mild 350 in my garage that doesn't have a home yet and I am considering swapping it with my tired 305 in my 1993 k1500 5-speed. I DO NOT want to go backwards to carburated since this truck will be driven through all 4 seasons and I NEED it reliable.

The 350 has between 350-400hp and was used in my drag car before I blew out the transmission in it so it is defiantly not a stock engine. I was just going to freshen it up with new rings, bearings and gaskets before the swap.

Can I upgrade the stock TBI system to handle thins engine reliably whether that be bigger injectors or using a 454 TBI, or....? And how much should I expect to pay for the TBI/computer mods before it is reliable? And what all is involved with tuning a TBI as I've never done it before?

Or should I use a stand-alone self-tuning unit like the one in the link below? I just replaced the fuel pump in this truck last year and not sure how much PSI a stock replacement can handle, can it get up to the 45 PSI that unit needs?

https://www.summitracing.com/parts/fif-30003/overview/

I'm trying to keep this swap below $1000 if possible.

Thanks for your help and ideas!

 

[Supercharged111]

Could you post the specs of the engine so we can make a more accurate determination of your needs? Heads, cam, cr, etc.

 

[RichLo]

2.02/1.60 World Products S/R Torquer heads w/170cc intake, 10.5-1 compression. I forgot the cam specs off hand, its a smooth idling cam though.

 

[Chewy1576]

Check out www.gearhead-efi.com for some tuning info and advice. You could be well under $1000 by using the TBI system with some mods. With the 383 in my 1990 K2500, I've done an 16197427 ECM swap and tuned it to run 80 lb/hr injectors. I have a bored out intake and a big block TB with 61 lb/hr injectors and adjustable FPR ready to go on also to try to squeeze more out of it.


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[Supercharged111]

Cam specs would be good to have, but I have little doubt the tbi system couldn't be made to work. I have a friend with a vortec 350 and hot cam that he's tuni g with ebl flash. That's an awesome option.

 

[90halfton]

If I was to so much as change the color of the valve covers I would put an aftermarket throttle body setup on it. Tbi's are exceptional on a stock motor ( compared to a carb anyway), but can be a pain to tune. Ebl seems to be the best option if you want to tune it yourself, which I'm sure you're capable of if you're rebuilding the motor yourself.

 

[RichLo]

I just looked up that EBL flash that you mentioned. Its $380 for them to modify my computer and send it back or $430 to get a different computer and keep mine as a spare. Then I would need to find a 454 throttle body ($100ish used), rebuild it, modify it with adjustable fuel pressure regulator, buy new high flow injectors ($120), and possibly need to buy a new high pressure fuel pump anyway. Then I could start tuning from scratch with no guarantee that will even be enough to support this engine. So, I could be out $650ish without anything to show for it.

Although it would be cool to tune my own engine with a laptop and have all the extras that EBL offers, I might end up getting that stand-alone self-learning unit above for $800. It seems like way less of a headache and if it doesn't work for whatever reason, I'll know right away and I can return it and try something else.

By the way, this is the EBL website I found if anybody is interested:
http://www.dynamicefi.com/

Thanks for your help, I wasn't sure how versatile the EFI system was and although it could work with a lot of tuning and modifications, with the prices of stand alone units going down its hard to justify not getting one at this point. If I was swapping a stock 305 for a stock 350, that would be different though.

I dont think its going to happen for under $1000 but oh well, I'll save up for it and take it in steps this summer.

 

[Chewy1576]

The EBL is a great ECM, but expensive. You could swap to a very tuning friendly 16197427 ECM from the 94-95 Trucks/SUVs/Vans (I just bought one from a junkyard for $35), pick up the hardware needed to burn/mount custom chips and data log ($200 or so from moates.net), and TunerPro RT and any software needed is free.

80 lb/hr injectors with 24 psi of fuel pressure will support 400 hp. The big block TB will flow more than enough air. The EP381 pump will support up to 60 psi of fuel pressure and is a drop in replacement for a TBI sending unit ($34 on eBay for the whole replacement kit). You also get to maintain the TBI electronic spark control.

It would take some work and there would be a learning curve, but your proposed set up is more than capable of running your engine.

 

[RichLo]

ok, Thank you for that info!! I'm going to have to keep looking at my options and get some more prices together. It's good knowing your running a 383 successfully off a TBI system.

 

[ccreddell]

OK, I may or may not be the friend S/C111 is talking about, but I am running Vortec heads, an LT roller cam, Headers with 2.5" Y and no cat into 3" and a Flowmaster. Electric fans, Edelbrock 4V manifold with adapter, and a heated O2. Im running 1.6 roller rockers also. And, I have the EBL. I ordered the daughter board and soldered it in myself and saved a bunch of money. the tuning suite is free (TunerPro RT), and the learnuing curve is steep-but doable. My truck pulls like a freight train all the way through the gears, shifting at 5500 with no problem at all and I have gotten as high as 25mpg on the highway at a steady 75mph. All this is with a stock TBI with regular 350 injectors running about 20 psi fuel pressure. Oh, and one of the things most people overlook is the air cleaner. Almost every TBI A/C Ive seen has the choke flap permanently stuck closed-and no one notices it. That, I believe, is why everyone thinks the stock TBI cant flow enough for a 350. It just chokes it off. Thats probably why running the lid upside down works so well and why people swear an open element A/C gives them 20hp-cuz it probably did. I removed mine completely and havent had any trouble even down to 0 degrees here in winter. I do take the air intake out of the fender when it gets that cold, but it still runs just fine.

If you do decide to run an aftermarket EFI, youll have to figure out how to run all the rest of the engine and guages, because the aftermarket computer wont.