Qjet to FITech 3003, couple questions

[Elkhider]

1979 K20 with a stock 350, went from a disfunctional Q-Jet to a FITech 3003, using a Holley in tank pump in a new saddle tank. So far it's nice, I don't think the truck has ever run better. To be able to jump in, turn the key and drive without it tripping over it's own shoelaces is pretty darn nice and I'm never going back to carb.
However since the 3003 supports up to 400 HP I'd like to get there. Right now it's a stock intake and stock exhaust manifolds, cat deletes with duallies running turbo mufflers, and all the external smog stuff gone. So since I'm no longer needing a strong airflow.vacuum system to draw air and fuel through the carb, can I go ahead, go single plane, headers and cam er up some with the expectation that the EFI will handle the fuel closed loop, basically run the air through? Not expecting huge speed from a K20 with full time 4wd to be all that fast but I would like quick.
Also, if anyone is on the fence about converting to EFI, or has questions, let me know. I've worked out the install using the rather cryptic instructions and some head scratching but yes, happy with it so far, and wouldn't go back.

 

[Aubie Spr96]

Just made the same conversion on my '86 Suburban with the 454. I won't go back either. I'd like to get it dialed in more for fuel efficiency. Getting new exhaust system soon.

 

[SquareRoot]

Getting a stock 42 year old 350 up to 400 hp might be a little on the ambitious side. Maybe a 300 shot of nitrous will get you there but it will only happen once and it will be over quickly so don't blink.

 

[consti2tion]

Just made the same conversion on my '86 Suburban with the 454. I won't go back either. I'd like to get it dialed in more for fuel efficiency. Getting new exhaust system soon.

How did the conversion go on your 454? I've got an 86 Suburban with a 454 that I am piecing the stuff together to convert mine to EFI, I've ordered an 87-91 tank and sending unit, so I can have the internal fuel pump. Still haven't decided which EFI I want to go with either the Sniper or the FiTech. I have not seen a lot of positive stuff about the Fitech as far as reviews but I feel like a lot of that has to do with the installation. As we all know people are much more likely to leave a bad review before they leave a good one.

I'm going to be swapping out the T400 with a 4L80E I picked up awhile back. The TPS solution if I go with the Sniper will be an additional TPS as it appears you cannot tap into the TPS of the Sniper.

 

[bluex]

How did the conversion go on your 454? I've got an 86 Suburban with a 454 that I am piecing the stuff together to convert mine to EFI, I've ordered an 87-91 tank and sending unit, so I can have the internal fuel pump. Still haven't decided which EFI I want to go with either the Sniper or the FiTech. I have not seen a lot of positive stuff about the Fitech as far as reviews but I feel like a lot of that has to do with the installation. As we all know people are much more likely to leave a bad review before they leave a good one.

I'm going to be swapping out the T400 with a 4L80E I picked up awhile back. The TPS solution if I go with the Sniper will be an additional TPS as it appears you cannot tap into the TPS of the Sniper.

Sniper all the way. The Fitch isn't as user friendly an they will not give you any computer software for it so you have to do everything through the small screen.

Installation errors are the root cause of 90% of people's issues. The other are not wanting to learn the systems or program them them selves. Pay attention to the instructions an follow what they say. Do the wiring correctly an make sure the engine an factory wiring are all in good working order. Carbs can compensate for issues that an efi won't tolerate.

As far as the tps on the Sniper there is a splitter plug available. Some people have had good luck using it to control a trans. It's a third-party piece, I can't remember who makes it but it's out there. Obviously holley doesn't recommend it but you could try it before spending the money on an additional sensor.

 

[Bextreme04]

Doing anything without improving the heads and bumping up the compression is going to be minimal at best. Stock 79 smogger heads with 7.8:1 compression is never going to get anywhere near even 300hp, no matter what else you do. Your best improvement will be small chamber aluminum heads. Next biggest would be cam. Then the single plane(which is only for better manners with the fuel injection). Headers are going to be a nice small improvement because of all the other airflow improvements, not instead of.

I would recommend you get a set of AFR heads from Skip white performance and have them match the springs to the cam you decide to go with.

 

[SquareRoot]

Sniper sucks! Ask me how I know. Your better off to spend just a few more dollars and buy a "real" fuel injection system and install a factory type fuel delivery system. I've had them all and Edelbrock pro-flo has always been superior in my experience.

 

[consti2tion]

Sniper all the way. The Fitch isn't as user friendly an they will not give you any computer software for it so you have to do everything through the small screen.

Installation errors are the root cause of 90% of people's issues. The other are not wanting to learn the systems or program them them selves. Pay attention to the instructions an follow what they say. Do the wiring correctly an make sure the engine an factory wiring are all in good working order. Carbs can compensate for issues that an efi won't tolerate.

As far as the tps on the Sniper there is a splitter plug available. Some people have had good luck using it to control a trans. It's a third-party piece, I can't remember who makes it but it's out there. Obviously holley doesn't recommend it but you could try it before spending the money on an additional sensor.

The shift controller I am going to go with is the US Shift Quick 2(Baumann), they offer a splitter/filter for an extra 75 dollars. I have found a guy that sells the add on TPS for about 140 dollars here.

Solution for Seperate TPS for Transmission Controller on EFI

Shop here to buy unique OEM style kit for adding a second Throtttle Position Sensor onto aftermarket EFI systems such as Holley, FiTech, and other brands.

eficarb.com

I figured would it be wise to just spend the extra 65-70 to avoid any potential issues? Thank you for the insight bluex!

Sniper sucks! Ask me how I know. Your better off to spend just a few more dollars and buy a "real" fuel injection system and install a factory type fuel delivery system. I've had them all and Edelbrock pro-flo has always been superior in my experience.

I have read some of your woes with it and I can understand how you would not suggest it for sure. With that being said the Edelbrock Pro-Flo is 2500 vs the roughly 1000 for the sniper. It also seems like a bit overkill for a stock 454. Thank you for all the info you have put out there for us though! It's greatly appreciated.



I've also found a complete 87-91 Suburban with a 454 that I have considered purchasing for the TBI stuff, but that just sounds like a complete headache.

 

[Bextreme04]

The shift controller I am going to go with is the US Shift Quick 2(Baumann), they offer a splitter/filter for an extra 75 dollars. I have found a guy that sells the add on TPS for about 140 dollars here.

Solution for Seperate TPS for Transmission Controller on EFI

Shop here to buy unique OEM style kit for adding a second Throtttle Position Sensor onto aftermarket EFI systems such as Holley, FiTech, and other brands.

eficarb.com

I figured would it be wise to just spend the extra 65-70 to avoid any potential issues? Thank you for the insight bluex!


I have read some of your woes with it and I can understand how you would not suggest it for sure. With that being said the Edelbrock Pro-Flo is 2500 vs the roughly 1000 for the sniper. It also seems like a bit overkill for a stock 454. Thank you for all the info you have put out there for us though! It's greatly appreciated.



I've also found a complete 87-91 Suburban with a 454 that I have considered purchasing for the TBI stuff, but that just sounds like a complete headache.

I would never buy a TBI 454 just to get the fuel injection. You would be better off just buying an entire L29 454 from a junkyard out of a 97-2000 Pickup/suburban. Then you would have higher compression, roller cam, better flowing heads, AND MPFI. Get yourself an 0411 ECU and pigtails for $50 from the same yard and now you have a fully fuel injected 454 and the factory transmission control as well. There is also tons of support for the stock L29/4L80 being run by an 0411 computer, as it is a super common swap on the factory trucks/suburbans. You can sometimes find complete L29's for $500-800 dollars with the harness and computer included. They are factory rated at 290hp/410ft-lbs of torque, which is way better than the TBI motors. There are several dyno videos of a straight junkyard L29 with a carb and headers making well over 300hp and almost 500ft-lbs of torque on 89 octane with no issues at all.

Either way, I'd recommend a good cam and a single plane intake if you are keeping the motor you have and decide to go with the sniper or similar system. Going to an L29 wont require changing anything, although I would also again recommend a new cam or regrind of the stock cam. You can put a stock ZZ502 cam in one without having to change anything else.

 

[consti2tion]

I would never buy a TBI 454 just to get the fuel injection. You would be better off just buying an entire L29 454 from a junkyard out of a 97-2000 Pickup/suburban. Then you would have higher compression, roller cam, better flowing heads, AND MPFI. Get yourself an 0411 ECU and pigtails for $50 from the same yard and now you have a fully fuel injected 454 and the factory transmission control as well. There is also tons of support for the stock L29/4L80 being run by an 0411 computer, as it is a super common swap on the factory trucks/suburbans. You can sometimes find complete L29's for $500-800 dollars with the harness and computer included. They are factory rated at 290hp/410ft-lbs of torque, which is way better than the TBI motors. There are several dyno videos of a straight junkyard L29 with a carb and headers making well over 300hp and almost 500ft-lbs of torque on 89 octane with no issues at all.

Either way, I'd recommend a good cam and a single plane intake if you are keeping the motor you have and decide to go with the sniper or similar system. Going to an L29 wont require changing anything, although I would also again recommend a new cam or regrind of the stock cam. You can put a stock ZZ502 cam in one without having to change anything else.

That's also a good point here. If I could find a good enough deal on an L29 with harness it would potentially cost less than a Sniper kit and the trans controller. I would then have a good 454 to build on for my 1970 Nova roller. I will really have to look into this. I didn't realize that they could be had for such little money. The thought of having a roller engine with MPFI is really appealing to me. I would likely keep it pretty stock as I am not looking for a hot rod, just a good low end puller to drag our vintage travel trailer around (around 4500-5000lb aluminum trailer) so the factory ECU for the L29 would suffice even with a small cam correct? Thank you Bextreme04 for helping me think outside the box! The thought hadn't really crossed my mind.