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Username Post: Electronic Fuel Injection, 305CI        (Topic#365892)
drice0517 
Newbie
Posts: 39

Reg: 01-21-21
07-23-21 06:38 PM - Post#2823783    

Tired of fooling with the Quadrajet carb on my 85...all stock 305 with a Rochester Quadrajet, single blade electronic choke system. I'm thinking about replacing it with an electronic fuel injection system like the Holly Sniper. Not looking to hot rod or anything, just a better running, more dependable truck. I understand my gas milage would be somewhat better too. Anybody have any experience with these systems on small block motors..?

1985 GMC Sierra Classic, C1500
305 CID, 4 bbl Quad
Stock Configuration


 
gchemist 
Member #271 Senior Chevytalk Moderator
Posts: 25520
gchemist
Age: 51
Loc: Austin, TX 78748
Reg: 05-09-00
07-24-21 04:17 AM - Post#2823794    
    In response to drice0517

Is your motor original or rebuilt?
I’ve looked at a few systems to add FI to my ZZ4. TBI is easier than MPFI. Adding an O2 exhaust bung and fuel pump are the hardest parts. Do you prefer an in tank pump? Or a frame rail pump?

'83 Silverardo XST - ZZ4 powered
'95 Jimmy SLT (Bought @131,814)
'96 GMC Jimmy LS Ret. @236651 miles
'08 GMC Acadia 3.6L SLE


 
wagonman100 
Site Ambassador
Posts: 15320

Loc: Baltimore, MD
Reg: 11-27-04
07-24-21 11:40 AM - Post#2823813    
    In response to gchemist

It’s a bit more than just an O2 sensor and pump. You will probably have to upgrade you fuel lines for the added pressure, you may need a speed sensor for you transmission, you typically need a MAP sensor, temperature sensor, coolant temperature sensor, and depending on the type of system, a MAF sensor. Sounds like a lot, but it’s actually fairly easy.

Jay
Friends don’t let friends drive Fords.

1999 Silverado Z71 4X4 extra-cab short bed
1983 Malibu Fauxmad - tubbed
1978 El Camino Kustomized
1972 Monte Carlo
1957 210 handyman wagon
1957 Nomad sport wagon
1957 Cameo Carrier


 
drice0517 
Newbie
Posts: 39

Reg: 01-21-21
07-25-21 01:36 PM - Post#2823875    
    In response to gchemist

It's a stock 305...I need to replace the fuel gauge sending unit while I'm at it, so if the mechanic can use the in-tank pump that works for me. On the other hand if he uses the frame mount, replacing it later on if needed would be a lot easier...

1985 GMC Sierra Classic, C1500
305 CID, 4 bbl Quad
Stock Configuration


 
drice0517 
Newbie
Posts: 39

Reg: 01-21-21
07-25-21 01:46 PM - Post#2823877    
    In response to wagonman100

Thanks for all this information on the sensors wagonman. I'm not doing the work, a local restoration and speed shop will do the work. Mechanic says he has done several SBCs but not specifically a 305...he's taking a few days to do a little research to make sure everything will conform to and work out on the installation for the 305. I plan on him replacing my dual exhausts with a new exhaust system while he has the truck and as stated in my other post to gchemist, a new fuel sending unit.
I'll ask him about all the sensors and make sure how they might impact my original gauges and transmission shifting. I really don't want to add any aftermarket gauges, etc. I'm supposed to talk with him early this coming week after he makes sure everything will work out. I'll post when I get some answers....thanks for the info guys..!

1985 GMC Sierra Classic, C1500
305 CID, 4 bbl Quad
Stock Configuration


 
gchemist 
Member #271 Senior Chevytalk Moderator
Posts: 25520
gchemist
Age: 51
Loc: Austin, TX 78748
Reg: 05-09-00
07-25-21 02:08 PM - Post#2823878    
    In response to drice0517

Which system is on review? For a 305, a two barrel TBI unit will work. The transmission speedo can be adapted with a signal generator. No need to change the speedo. My aftermarket cruise control has a signal generator. A signal generator goes in line with the cable.

'83 Silverardo XST - ZZ4 powered
'95 Jimmy SLT (Bought @131,814)
'96 GMC Jimmy LS Ret. @236651 miles
'08 GMC Acadia 3.6L SLE


 
drice0517 
Newbie
Posts: 39

Reg: 01-21-21
07-25-21 06:51 PM - Post#2823892    
    In response to gchemist

I think we're looking at the Holly Sniper kit from Summit Racing...kit comes with most of the parts needed for installation. I'll get abetter idea after I talk with the shop guys...they may point me in a different direction...I'll post later...

1985 GMC Sierra Classic, C1500
305 CID, 4 bbl Quad
Stock Configuration


 
wagonman100 
Site Ambassador
Posts: 15320

Loc: Baltimore, MD
Reg: 11-27-04
07-25-21 07:23 PM - Post#2823897    
    In response to drice0517

If he has done other small blocks, he will know what to do and what is needed. First gen Chevy small blocks are all pretty similar. I don’t know if you put in the engine size when ordering the kit from Holley. A 305 will need smaller injectors than a 350.

Jay
Friends don’t let friends drive Fords.

1999 Silverado Z71 4X4 extra-cab short bed
1983 Malibu Fauxmad - tubbed
1978 El Camino Kustomized
1972 Monte Carlo
1957 210 handyman wagon
1957 Nomad sport wagon
1957 Cameo Carrier


 
drice0517 
Newbie
Posts: 39

Reg: 01-21-21
07-26-21 03:52 AM - Post#2823901    
    In response to wagonman100

I agree wagonman...I think he's looking at the Holly Sniper Quadrajet kit from Holley or Summit Racing. I'm hoping the fact that he's taking time to research the job speaks well for his work. I haven't used this shop before and as I've discovered over the past few years, not every shop has the experience or knowledge when working on older vehicles.

1985 GMC Sierra Classic, C1500
305 CID, 4 bbl Quad
Stock Configuration


 
gchemist 
Member #271 Senior Chevytalk Moderator
Posts: 25520
gchemist
Age: 51
Loc: Austin, TX 78748
Reg: 05-09-00
07-26-21 01:43 PM - Post#2823927    
    In response to drice0517

Holley two barrel options look good. No need for one above 350 HP. No hassle fuel regulators required. An in tank fuel pump would be an option. The master kit has a frame rail mounted pump.

'83 Silverardo XST - ZZ4 powered
'95 Jimmy SLT (Bought @131,814)
'96 GMC Jimmy LS Ret. @236651 miles
'08 GMC Acadia 3.6L SLE


 
gchemist 
Member #271 Senior Chevytalk Moderator
Posts: 25520
gchemist
Age: 51
Loc: Austin, TX 78748
Reg: 05-09-00
07-26-21 01:55 PM - Post#2823929    
    In response to gchemist

A C10 with a Holley Sniper FI upgrade. However, this one has a Caddy engine!

'83 Silverardo XST - ZZ4 powered
'95 Jimmy SLT (Bought @131,814)
'96 GMC Jimmy LS Ret. @236651 miles
'08 GMC Acadia 3.6L SLE


 
drice0517 
Newbie
Posts: 39

Reg: 01-21-21
07-30-21 04:07 PM - Post#2824178    
    In response to gchemist

Finally talked with the shop owner and got an estimate on installing a Holly Sniper EFI system on my 305. The system comes complete with everything needed to install it, including an in-tank pump/sending unit and all the sensors. The estimate is approximately $4800 for everything. This includes "cleaning" up and my engine bay wiring and hoses during the installation. At first I thought that was a whole lot of labor (he estimated 35 hrs.), because the complete Holly system is about $1600-1800 for everything, but after meeting him in person and talking with him, I got a better idea of what all is involved with the installation. Because of the expense of installing the EFI I've asked him to work up another estimate for just replacing the carburetor and "cleaning" up the hoses and wiring, and putting me a new sending unit in my fuel tank. I'll make up my mind which way to go next week. I know you usually get what you pay for, but I'm just not sure I want to put the much money in the EFI...I plan on keeping the truck and driving it daily, so better gas milage would be a big plus, so I'm leaning toward getting some work done one way or the other...you folks have any experiences with other EFI systems or replacement carburetors..? Advice...? Pros and Cons..? Appreciate your time...!!

1985 GMC Sierra Classic, C1500
305 CID, 4 bbl Quad
Stock Configuration


 
Stinky 
Senior Member
Posts: 1763

Loc: Whitewater, CO
Reg: 05-25-01
08-02-21 01:05 PM - Post#2824312    
    In response to drice0517

I think that you should save yourself about 3,000 bucks and do it yourself.

What you are talking about doing is not hard to do...although it is a PITA to drop a tank. Can you go w/a frame rail mounted pump?

For the 2bbl option...you are gonna need an adapter plate. If I remember right, they are sorta hard to come by as it is adapting a Ford 2bbl to a Qjet manifold.

My guess is that Holley would have one as they don't make a Q-jet replacement 2bbl.




Edited by Stinky on 08-02-21 01:11 PM. Reason for edit: No reason given.

 
drice0517 
Newbie
Posts: 39

Reg: 01-21-21
08-02-21 03:00 PM - Post#2824333    
    In response to Stinky

I hear what you're saying about the $3K Stinky, but I don't have the patience and place to tackle this job...if it was a SBC without all the emissions stuff, say, back in the 60-70s, I might try it, but this GMC is all original and the engine bay is full of all kinds of hoses, vacuum lines, and electrical wiring. At this point in my life I'd rather pay to get it done right and be done with it. The trick is getting it done right and then tuned right. From what I've read and with what I've learned talking with several local younger mechanics, it won't be a simple plug and play, and some included manufacturer's installation instructions are vague or just plain wrong. I haven't used this particular shop before and there aren't many around here that works on the older stuff. I wanted to go with in-tank pump for noise reduction. They tell me the frame rail mounted pumps are seriously noisy. This shop has installed a number of these systems on local cars/trucks so we'll see how it goes with this next estimate. Not sure what you mean about the 2 bbl and adapters. Is the Holly Sniper or all EFIs in general 2 bbl for the smaller horsepower/cubic inch ranges..? I thought it would be a 4 bbl to 4 bbl swap and only need an adaptor for any spread bore differences. Am I missing something..? I'm leaning toward a standard brand new 4 bbl. carb to replace the Rochester and a new exhaust system, which will be a heck of a lot cheaper and might serve me just as well for now. Appreciate the advice and your time sir...!

1985 GMC Sierra Classic, C1500
305 CID, 4 bbl Quad
Stock Configuration


 
1965C-10 
Very Senior Member
Posts: 7698

Age: 43
Loc: San Tan Valley AZ "Phoeni...
Reg: 11-18-01
08-02-21 03:36 PM - Post#2824336    
    In response to drice0517

I'm putting Edelbrock Pro Flo 4 multiport fuel injection on the 396 big block I swapped into my 1965 C10.

Still working on it, but it should run good.

The kit I bought came with a tablet it was $1895.00 plus tax and got a free fuel sump pump from Edelbrock with rebate, uses mechanical fuel pump to fill Edelbrock sump fuel pump, that bumps up the fuel pressure to what is needed for fuel injection.

Located the sump fuel pump right behind bumper in passenger side wheel well to try to avoid heat from engine bay.

This system self tunes by driving, but you can also adjust things on it with the tablet, or your smart phone android type with Edelbrock app installed while engine is running.

It also came with a distributor.

You choose maps for what your engine is, put in type like SBC BBC ford , dodge etc, displacement and choose the cam type stock, mild or wild and it should fire up.

It self learns as you drive.

It also has ability to accept turbocharger or centrifugal supercharger and can tune for that too.

On the Edelbrock pro Flo 4 forum, there are several people who had Holley Sniper, the more expensive multiport version and gave up because they could not get it to run good and others has issues with it running and not running.

Of course the Edelbrock system may need time to dial in to get tuned, that's what the forum is for to assist you.

You might be better off with just getting another carburetor, keep your factory one just in case for future use.

I wanted to swap to LS1 or LS3 engine but decided to make my 396 high tech instead as a compromise.

My quadrajet was temperamental run good one drive, run like crap next day, that's reason I went to fuel injection.

Sorry cannot personally review the Edelbrock pro Flo 4 yet as I'm still working on it.

It did come with wide band O2 sensor and sensor bung, took my passenger side exhaust pipe off drilled hole with step bit, brought it all to exhaust shop to have bung welded as I don't weld or own a welder.







 
1983G20Van 
Super Senior Member
Posts: 3893

Loc: Bedford, Texas, USA
Reg: 11-13-02
08-02-21 08:54 PM - Post#2824362    
    In response to 1965C-10

Easiest thing to do is get a tank and sending unit/pump assembly for an 87 R10. Some AN lines and fittings to run the lines. Grab a stock intake and TBI along with the distributor, coil and all the brackets from the scrap yard. I like pillaging them from later 80s full size vans because they are generally better protected from the weather. Grab the ECM and make sure it is from an 87-92 with a TH400 or 700r4. Slot the 4 center bolt holes on the intake manifold. 10-15 years ago I used the van harness from the wrecking yard. As old as the TBIs are now I would get a Painless harness and all new sensors. Its hard to beat the reliability and diagnostic procedures of the OEM. My 83 G20 needed minimal vacuuum connections after the swap. I hooked a vacuum line to ported vacuum for the TCC lockup switch and hooked the vapor canister back up. All the other vacuum junk is practically eliminated including the emissions air pump and lines.


1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals


 
drice0517 
Newbie
Posts: 39

Reg: 01-21-21
08-04-21 07:54 AM - Post#2824462    
    In response to 1983G20Van

Thanks for the input Van and C10. Based on some replies and talking more with local truck owners this week I've decided to go back with a new carb, intake, fuel pump, sending/pick up unit in the tank. Waiting on an estimate for the parts/installation. Mechanic wants to get a used/new intake that would better match the new carb. He thinks he can find a good used one locally that will do the job. Checking on a Holly 570 for the 305. Seems to me no matter which way you go, it's going to be all about the tuning, good vacuums, and timing to get it running good again. Hopefully, I'll have a good estimate and a final decision soon. I'll keep y'all posted...appreciate it...!

1985 GMC Sierra Classic, C1500
305 CID, 4 bbl Quad
Stock Configuration


 
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