Holley Sniper Question

I am building a 482 for the street. The expectation is 550-600 for both HP and Tq. I am trying to decide between rebuilding the quadrajet or going EFI. The Holley sniper line seems to be pretty popular but I’m going to have a bit more HP than their Quadrajet style model which is rated for 500HP and is the only one offered specifically for a spread bore manifold (Holley SPX in this case).

They make models rated for 650HP (super sniper) and 800HP (XFlow) which only come in square bore but according to the Holley website, these seem to fit spreadbore manifolds with a recommended gasket kit.

I have two questions:
1. Is anyone running a square bore sniper on a spreadbore manifold?
2. How does the height compare to a quadrajet? Hood clearance is an issue and I’m already 1.5” taller than stock with the SPX

Thanks in advance. - Rich

 

Switch intakes and use a squarebore EFI.

 

I am not 100% sure if this answers your question but the SNIPER come with 8 holes for 2 different patterns. At least mine does ( Super Sniper) Just call teh Holley peops they will help you
I have my sniper on a boosted setup ...it runs great. Much better than the Blowthrough carb.
the height is pretty much the same as a Qjet.

If you dont have the fuel delivey sorted out yet for EFI (58-60psi needed) i recommend a Surge tank feed by the stock mechanical FP and from the surge tank to the EFI. I have a Robb MC, but edelbrock has them too.

Another tip , order from SUMMIT they have most of it on the shelves, Holley is out for another 12+ weeks!

 

I agree this would be easiest if I didnt already have the spreadbore SPX and parts were easy to get -the one I got was the last one TA had for a while from what I understand.

Are you saying to change manifolds beacause you know of some incompatibility?

 

Thank you - very helpful

 

Great info - thanks Larry

 

I stand corrected, listen to Larry. Your intake should work fine with a square bore efi.

 

No disagreements with Larry and Sean. I will add I'm going down a path with a machined down SPX and square bore Accufab 4150 style which combined has same height as quadrajet plus factory intake 400/430/455.

 

Just starting to get serious about buying a Sniper unit. I've got a very healthy 455 that desktop dyno's (previous owner/builder provided this when I bought the car) at about 675 HP. I'm not sure I buy the 675 HP but the engine is no joke at all and compares well to cars I've driven with 600 +/- HP.

The Super Sniper 1250 seems to be a good match for my engine and intended use? (I intend to use the car on the street as a "hot" cruiser type rig. Not a lot of "race" but up for an occasional trip to the track?) The carb that's on the car leaks fuel a fair amount.



Question: Rather than work on the carb a bunch, it seems like I should just go to the Sniper system like I intend to do?

 

My input here will be from the fuel tank end. I went with a Tanks inc tank and can not hold fuel pressure when the tank is below 1/2 full.
It does fine above that but will not support the needed fuel pressure below that. Not saying that I could have gotten a bad tank but I won't chance another one.

 

This should work in your stock fuel tank.

Holley Sniper EFI 12-373 Holley EFI Fuel Tank Modules - 350 LPH

This should work up to 650HP

Holley Sniper EFI 550-873 Holley Super Sniper Stealth 4150 - 650HP - Shiny Finish



.

 

I had no issues with my Tanks Inc tank. I went with the notched corner one with a 340lph pump.

 

Are you able to monitor your fuel pressure and injector duty cycle?

 

My 2 cents and posted in a previous discussion already.

let the stock mech pump and the stock tank work.
Just feed from stock mech fp to a external surge tank that has a electric FP (bosch 044) in it ( fits behind the headlight) and feed from surge tank to Sniper
the sniper has a internal regulator. this mod costs you 100-300$ depending what surge tank you want.

 

With the sniper only injectors can be monitored. The Super Sniper has the ability to monitor fuel pressure with the extra inputs. You can always add an external gauge, sure you know that. I never put a fuel pressure gauge on mine. I was lucky I guess car fired right up and ran just as good as the carb.

 

I had a Holley Terminator EFI system on my 455 with an Edelbrock B4B manifold. I used a square bore adapter and it ran fine. The adapter is thin, only about an 1/8” thick.

 

How do you like the sniper? Was it difficult to set up?

 

extremly easy.
i love it

 

I've got 10,000 miles and about 5 years on a Holley Sniper. The only trouble I've had is a common issue with the injector wiring plug coming loose. They aren't held in very securely. It's only happened on 1 of the 4 injectors.