Holley Sniper EFI in a 94 k1500

[danpro]

So a while ago I decided to replace the engine in my truck(350TBI) with a crate engine from jegs. Unfortunately, I didn't do my research and I bought a standard 350, the one they have for $1450 instead of the direct replacement they have for the 350tbi trucks for $1800. Anyway, I had to adapt the intake and everything to fit because of different bolt patterns and the truck runs decent but still isn't running as great as it should, possible because of cam differences and timing. Either way, I've fully restored this truck and plan on keeping it for a while so I've decided to ditch the TBI fuelling and go to a real EFI setup, the Holley Sniper. Sourcing parts for the swap like an HEI distributor etc and a carb'd intake is not an issue as I understand that having a 4l60E ill have to keep the TPS for the tranny to work. My only question is, being that it'll be essentially replacing most of the computer controlled system for the truck, will any sort of PROM chip for the ECU be necessary? The thing holding me back right now is just to make sure that theres nothing that a quick trip to a parts store will hold me back from completing this swap. I live in a cold climate so carbing the truck is not something I want to do, even though I know its cheaper. At this point, throwing another 2k for the swap in is not the biggest deal considering how much I've already spent. Thanks for any advice.

 

[Hipster]

The biggest thing is you swapped out a 64cc headed 9.4-1 compression engine for a maybe 8.5-1 76cc open chamber headed engine or so it sounds and that would cause a bit of power to be MIA.

 

[danpro]

The biggest thing is you swapped out a 64cc headed 9.4-1 compression engine for a maybe 8.5-1 76cc open chamber headed engine or so it sounds and that would cause a bit of power to be MIA.

Definitely has a lack of performance compared to what it had, setting timing to 0 degrees with the wire unplugged was not enough for that cam because it was stuttering just off slight acceleration a lot, soon as I made it a bit more advanced it runs like a kitty. The 35 inch tires with 3.73 gears don't help but thats for another day. The main thing im worried about is just if I put the EFI if i'll have to do anything to the computer already in the truck. My thinking is no because that efi system comes with everything you need and since the motor I put in was designed for a carb anyway, it'll run much better than this throttle body thats on it now.

 

[TylerZ281500]

youll need the computer in the truck to control the trans, at that rate your not gonna gain anything swapping the TBI out, do a proper cam and some better heads and it may resolve your issue

 

[danpro]

youll need the computer in the truck to control the trans, at that rate your not gonna gain anything swapping the TBI out, do a proper cam and some better heads and it may resolve your issue

I understand I'll need the computer for the transmission, I'll also have to figure out a way to put the TPS onto the linkage because the 4l60e also uses TPS to control. I'm not talking about eliminating the computer from the truck, its just that the MAP, EGR, distributor plugs will all be unplugged because all that will be controlled from this EFI system as well as having an HEI distributor. So everything thats left thats plugged into the factory ECU is stuff that has no bearing on spark and fuel/air. It even comes with a wideband o2 sensor which plugs into the new EFI unit. My only question is if theres anything I'm overlooking before I pull the trigger. The engine with headers and this EFI system will make around 250HP im estimating which is plenty for what I need it to do.

 

[Hipster]

I have been in a few of those crate engines, typically measured out 8.2 comp.. The 8.5 and 250hp figure is overly optimistic. If the stock stock stuff is pulling the timing correctly and keeping the afr's inline there is not going to be any magic hp/tq made by bolting on another throttle body injection system or carb. 1+ point in compression can make a big difference. The stock injection and 64cc heads might get you where you want to be at less cost and complexity as already suggested, and sometimes it's just better to leave the racecar stuff to the racetrack. Your not going to go in an Autozone anywhere to get anything sniper if it craps. The engine you put in is a less efficient low comp smog era engine. Also takes a different flexplate then the later 5.7 tbi/vortecs. Lower compression/power is going to equate to more throttle opening all the time.

 

[TylerZ281500]

250hp id say is way optimistic for its configurations, somewhat worthelss without engine specs though. im just saying sniper as great a system as it is is totally unneeded here.

 

[danpro]

250hp id say is way optimistic for its configurations, somewhat worthelss without engine specs though. im just saying sniper as great a system as it is is totally unneeded here.

I got that number based off jegs saying you can get up to 260HP with headers and a 4 barrel carb. This is the engine I bought: http://www.jegs.com/i/Chevrolet-Performance/809/10067353/10002/-1

 

[danpro]

Also, http://www.superchevy.com/how-to/en...torque-monster-for-3900-out-of-all-new-parts/ this article here uses the same engine and in picture 12, before bolting on a supercharger, with a air gap intake, carb and headers they made 287HP so I don't see how 250 is out of the realm of possibility, especially with a self learning EFI system

 

[Hipster]

Don't believe the hype. Can't really compare apples and oranges. Just another example of Magazine's misleading. That's 287 with an electric water pump, absolutely no accessories , full length equal length huge dyno headers, and no exhaust, corrected numbers. I'm sure it was dialed in and that is that engine maxxed out., and an efi would have made very similar #'s. You'll never see that hp in a vehicle turning a water pump/fan, steering pump, running 1 5/8 shorties, etc. Westech's dyno has been know to be overly happy for decades,