Marine Intake

[L31MaxExpress]

Decided to post pone the Proflow intake and put the L31 Marine intake back on the van. This manifold was worth 20-30 hp between 5,200 and 6,000 rpm on the 350 when it cammed compared to a ported truck manifold. Will be interesting to see how the 383 responds to it. This is a place marker for more pictures I take detailing the swap. Much of the older swap information is gone. I want to also provide infomation on swapping the harness to the matching Deatschwerks connetor so that an inexpensive AEM harness connects right up to the OEM harness like it was built that way. Both my OEM spider connector and marine intake have the Deatschwerks connectors on them. While I have it apart, I will show anyone that wants to know how to install that connector. Basically one cuts the OEM injector wiring after the 1st splice so that there are 4 remaining injector power feed wires on each side of the OEM injector connection wiring and grafting a plug on to it. Makes the intakes easily swapped with no wiring changes. I am leaving it that way in the event that someday I may have to put the OE intake back on for whatever reason. I did some port cleanup on the marine manifold, cleaned it up and re-painted it. Its going on tomorrow.

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[Komet]

What length of runners are in that thing? Interesting inlet location for sure.

 

[L31MaxExpress]

What length of runners are in that thing? Interesting inlet location for sure.

Same runners as a vortec truck.

 

[Singlecab]

I’ve been to the pull a part trying to cobble together some fuel supply/return for my marine intake project. I see your set up looks good. Is that earls stuff?

 

[Singlecab]

And your injector harness has a near factory main connector. Where did you source that?

 

[L31MaxExpress]

I’ve been to the pull a part trying to cobble together some fuel supply/return for my marine intake project. I see your set up looks good. Is that earls stuff?

Pure Choice

 

[Supercharged111]

Remind me again why you ditched the marine intake in favor of a ported stocker again? I'm more curious to hear how you deal with transient fueling with that. I've gotten mine better, but not perfect. Cold ECT fueling and VE/MAF not being perfect really exacerbate it.

 

[L31MaxExpress]

Started on it about 11:30 am after it warmed up outside after breakfast. Coolant is still draining from the engine block. Glove box and engine doghouse cover are removed. The a/c and p/s accessory bracket is loosened, ac compressor is laying there, air intake and coolant reservoir are out of my way. Last thing up front to remove is the throttle body and air hat. Then its time to remove the oil fill tubes and dipstick tubes, distributor, oil pressure switch and stand off pipe, some vacuum lines, fuel lines and a valve cover. Then it will be ready to remove the truck intake. I am pulling the Rhoads lifters out too. Not because they do not work, its actually the opposite. My compression ratio is so high that they work too well with my smallish cam. With them in place my dynamic compreasion ratio is around 9.5:1 at lower rpm which results in 230 psi cranking compression. I have an older set of low mileage, cleaned, stock GM lifters that are going into it. With stock GM lifters in the thing it should have a little more lope at idle too. I am putting the stock GM lifter retention stuff back in it too, to prevent the temptation from wanting to swap cams in this thing for the 2nd time.

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[L31MaxExpress]

Remind me again why you ditched the marine intake in favor of a ported stocker again? I'm more curious to hear how you deal with transient fueling with that. I've gotten mine better, but not perfect. Cold ECT fueling and VE/MAF not being perfect really exacerbate it.

Emissions, they started doing a visual which the marine failed. Its 25 years old now, so exempt in the state of Texas.

The transient fueling has never been great on mine, even when it was stock. I just added to the Impact factor until the thing stopped popping back from the intake which it was doing even with the 350 and stock L31 manifold after I put a converter into it.

 

[Osteoblast]

Where can I find the l31 marine intake?