Best fuel injection intake?

[tpass]

Then stick with the factory Vortec injection. For the RPM range you are looking to run in, it works great.

0411 swap it and tune it.

I'd agree with this as well. Since you already have the L31, research your cam options, add a set of headers get an 0411 ecm and tune it.

 

[Schurkey]

My truck is a 98. It has the L31. So selling would be redundant. I'm not looking for advice on a swap. I already have that part down. Essentially I'm just replacing 350 engine guts with 400 guts and a bigger cam. If that makes more sense?

A 400 short block with a 350 top end.

That would be information to put in the FIRST post you made.

Several of us made an assumption that your current engine was TBI.

The L31 manifold with suitable injectors and tuning is still your most-cost-effective route. The added displacement will lower the power band; should be just what you wanted.

 

[L31MaxExpress]

That would be information to put in the FIRST post you made.

Several of us made an assumption that your current engine was TBI.

The L31 manifold with suitable injectors and tuning is still your most-cost-effective route. The added displacement will lower the power band; should be just what you wanted.

At the lower RPM he is looking to run especially with stock vortec heads and unported stock intake manifold, the MFI upgrade injectors should fuel a 400 easily to ~4,500-5,000 rpm. if the duty cycle starts to climb too high at the very top of the RPM, just set the tune to grab the next gear to take advantage of the stump pulling torque. Easier on the engine and transmission anyway.

 

[phantom 309]

i read about the mpfi marine intake for vortec heads,. ??

 

[L31MaxExpress]

i read about the mpfi marine intake for vortec heads,. ??

There are several marine options, but this is the one most often mentioned. I run one on my 383 and ran the same manifold on the old 350.

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[Schurkey]

Aren't those...scarce?

 

[Vikingdude]

Aren't those...scarce?

I've been checking forums and eBay for about two years now. I've seen one come up for sale, but splint into upper and lowers. Seller wanted 1500 for the two pieces, but didn't have fuel rails for it.

 

[Captainfab]

I would go with either a Edelbrock ProFlo4, ProFlo XT or a Holley StealthRam. Holley used to have a port efi intake with a 4150 flange for the Vortec heads, but they discontinued it.

 

[scrub_the_k1500]

I'd agree with this as well. Since you already have the L31, research your cam options, add a set of headers get an 0411 ecm and tune it.

Just a little update. Got all the parts on order. Reusing most of my top end from the 350, including the intake manifolds. I already bought a new upper 2 months ago. Might as well lol.

I got the new MFI conversion. I bought the kit from oreillys, they carry them at almost every store apparently. I know spider injectors are expensive. And this system cost just as much. It's part number FJ504 if interested. Puts the injectors at the end of the hose into the runner unlike the original system at the front of the hose. I'm sure most of you are familiar with this system.

Basically just gonna be a vortec 400. Might touch up on the heads, port them some and get some bigger valves. I'd rather invest my money into a 14 bolt and 6 speed auto swap. I have all the interior bits for a 2016 chevy truck too. But were getting off track.

I'll update this thread in a month or so with some numbers and parts. I'll go back and look at what I ordered and show what parts I ordered.

 

[L31MaxExpress]

Just a little update. Got all the parts on order. Reusing most of my top end from the 350, including the intake manifolds. I already bought a new upper 2 months ago. Might as well lol.

I got the new MFI conversion. I bought the kit from oreillys, they carry them at almost every store apparently. I know spider injectors are expensive. And this system cost just as much. It's part number FJ504 if interested. Puts the injectors at the end of the hose into the runner unlike the original system at the front of the hose. I'm sure most of you are familiar with this system.

Basically just gonna be a vortec 400. Might touch up on the heads, port them some and get some bigger valves. I'd rather invest my money into a 14 bolt and 6 speed auto swap. I have all the interior bits for a 2016 chevy truck too. But were getting off track.

I'll update this thread in a month or so with some numbers and parts. I'll go back and look at what I ordered and show what parts I ordered.

Are you staying with the flat tappet cam on the 400? I would suggest the Melling MTC1 if you do. Just a little more aggressive than the stock 350/400 cam. It is a 204/214 @ 0.050, 0.422/0.444 lift on a 112 LSA. It is a real stump puller in a 350 and what most call a "RV" cam. The 400 will need a Holley Timing cover to seal and the balancer will need 0.110" cut off the end of it. I came very close to building a 400 instead of a 383 for the van.