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Has anyone installed elec fuel injection on a 400 ci engine,  what injection did you use and what were the results.  I am kicking around the idea of changing from a 4 barrel to either tri power or ecec fuel injection. Like the looks of the tri power, but kind of like the idea of the fuel injection.   thanks in advance

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Thanks I will contact Butler, again Thanks

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Alway happy to help. Let us know what you decide to go with and why. We’d like to learn along with you.

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ok

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  • 2 months later...

3F5F40F8-D118-4CDB-9E0C-88F6D56ECCDD.jpeg

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The Holley X-flow 900 CFM works extremely well of a 468 Pontiac with a hyd roller cam. We made 500hp and over 550 ft lbs and have perfect cold starts, great fuel handling and better mileage than a factory carb.  We modified the stock iron intake to accept the X-flow, bolts right up with no spacer required. Factory air cleaner fits, no hood interference and much more HP than a RPM+ or Torker manifold.

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Edited by Stripes
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hay stripes, tell us what you have done to that manifold???

it looks like you had a dual plane and have made it into a spread bore type configuration ??? but its different, your first picture is of a square bore type throttle body🙄

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Sure. The picture is of the same Pontiac iron spread bore intake manifold. The Holley Sniper X-flow has duel bolt holes to allow it to bolt to either a square bore manifold or a spread bore manifold. The issue with a Pontiac factory intake manifold is as shown in the photo, the restriction would have been huge if it had not been modified.  To resolve the issue, we took a sawsall and grinder and opened up the manifold to the point that the Sniper would see no restriction. This resulted in huge power increases and no need to run any power robbing spacers.

Sniper does make a 650cfm spread bore fuel injection unit. I felt since the original carb was 700cfm with the engine in stock form, a 650 cfm would restrict my HP. I realize they claim it supports 600hp, but we can discuss what that really means and doesn't mean at another time. On the dyno the 800 holley 4150 made 40 more hp than the factory carb. Lets talk about what works well.

Additionally, the factory manifold was up about 20hp over the E RPM+ and the torker, from our dyno tests when the engine was assembled. Both of these aftermarket manifolds  had hood and air cleaner clearance issues, in the car, which also caused the top of the carb to sit too close to the top of the air cleaner with drop base air cleaners. The drop base air cleaners were required to allow the top to clear the hood on a 69 firebird. Additionally, the hp loss was recorded on a dyno with no air cleaners at all!  So unless you are running over 500hp, and larger than a 468 turning up to 6000 rpm, an aftermarket intake manifold is a losing proposition.  I believe an aftermarket intake with a drop base air cleaner could be over 30hp down. To be fair, I port matched all intake ports to the D port E heads prior to dyno testing, and the iron factory intake was matched to RA4 port sizes the E heads use. Heck, even the Edelbrock intake manifolds ports sizes are way small on their manifolds when matching to their OWN out of the box D port Aluminum E heads.

Now, the engine with fuel injection appears totally stock with the air cleaner on, and the performance and drivability improvements are huge! I highly recommend the Sniper X-flow (900 CFM). Of course the best part is there is no VAPOR Lock anymore as the fuel line has 58lbs of pressure instead of a vapor lock inducing vacuum on the fuel line. Fuel pump in the tank can not be heard or seen! Wheel spin is instantaneous. Recently at a car show a bystander walked by and said, look a totally stock Pontiac 400. I found that highly complimentary since this was now a 455 bored 60, with  forged rods and pistons, a hyd roller Comp cam, RA3 exhaust manifolds, HEI, and a 900 CFM Sniper FI making over 500hp and nearly 600 ft lbs of tq.

Here are some more photos of the manifold as we modified it.5AD6F404-2B0D-4763-9129-8AEBA36D3A20.thumb.jpeg.aef3193442251f11737f33e6794077d3.jpeg

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Ah very nice work Stripes 👍

 now i understand what you did and i certainly see the advantages :cheers:

and good move sticking the high pressure pump in the tank, it allows it to stay cooler and quieter, i have done this my self along with allowing a surge tray to ensure the pump picks up fuel, even at wot or hard cornering 😋

 and yes it just looks stock under the hood 👍

well done mate:bowdown:

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All I can add to that is, wow!!!

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