Marine Intake

L31MaxExpress

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I knew that other intake was all wrong for you. Good luck with the swap.
Its just hard to want to put alot more cam into it to really take advantage of that intake. The way this engine tugs at 1,000 rpm in lockup at 40 miles per hour on twisting, winding gravel roads without a care in the world changed my idea on that. I'll put some aluminum heads on the 350 that came out of the van and put it into my 2nd gen Camaro with a LS PCM and 24x ignition.
 

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One other attention to detail thing I missed on this intake. I will break out my machinest scribe, my grinder and carbides. That red lips gotta go. Marine intake plenum has a 78mm bore and the BBK throttle body has an 80mm bore. This engine needs all the air it can get.

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The again compared to the stock necked down to 70mm TB the BBK 80mm looks like it could inhale birds or other small animals at WOT.

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Singlecab

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What cam are you running? I have just installed the lunati cam that claims duration of 279/287, and a lift of 447/471. I did the springs. Still haven’t nailed down what rockers, but in my shopping cart currently are the comp magnums. I love the low rpm pull. Am I screwing up that characteristic with combining the marine intake?
 

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What cam are you running? I have just installed the lunati cam that claims duration of 279/287, and a lift of 447/471. I did the springs. Still haven’t nailed down what rockers, but in my shopping cart currently are the comp magnums. I love the low rpm pull. Am I screwing up that characteristic with combining the marine intake?
My cam is 271/284 @ 0.006, about 218/224 @ 0.050 and 0.578/0.510 lift with a 1.7/1.5 rocker ratio split, 108 LSA and 106 ICL. Larger rocker ratio is on the intake valve. Cam itself was ground 215/224 @ 0.050 but the rocker ratio changed the 0.050 duration a bit. I had a 1.7 on the exhaust too, but the 1.5 made a good bit more torque at lower rpm without sacrificing anything on the top. With the tri-ys and free flowing exhaust the large duration split over scavenges it.

As long as the tuning is good, the Marine manifold will only enhance your torque. The runners are slightly larger at the same length. The factory truck manifolds respond to port work to fix their poor casting quality with more torque and hp everywhere. The marine manifold takes it a step further by opening up the plenum area for even more airflow.
 
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Singlecab

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Yeah I’m going conservative compared to that, but the machine shop that did my head work said that I had a big cam. He also said with a roll of the eyes not to mess with my studs that factory would be fine. All I wanted was 350 hp. Most of what I’m doing is in the name of durability, and longevity. I’m concerned for drivability due to how light my truck is being a single cab short bed. I want it to still be a nice pleasant truck to drive. I would like that bbk throttle body in hopes of just a smoother pedal, but again I don’t want some fire breathing monster
 

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Yeah I’m going conservative compared to that, but the machine shop that did my head work said that I had a big cam. He also said with a roll of the eyes not to mess with my studs that factory would be fine. All I wanted was 350 hp. Most of what I’m doing is in the name of durability, and longevity. I’m concerned for drivability due to how light my truck is being a single cab short bed. I want it to still be a nice pleasant truck to drive. I would like that bbk throttle body in hopes of just a smoother pedal, but again I don’t want some fire breathing monster
Your cam has more duration than mine does. The BBK throttle body has a very aggressive tip-in off idle. Light touch of the pedal and it wants to go.
 

Singlecab

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I was only considering lift, but yeah duration probably translates to lope? I understand cams, but I’m slow and have to count with both hands each time I go through it. The motor still lakes complete assembly, and I certainly can’t return the cam, but i hope it’s manners remain modest.
 

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I was only considering lift, but yeah duration probably translates to lope? I understand cams, but I’m slow and have to count with both hands each time I go through it. The motor still lakes complete assembly, and I certainly can’t return the cam, but i hope it’s manners remain modest.
Overlap contributes to lope. A 104 or 108 LSA will have more overlap than a 112 or 114 LSA with all other specs equal. LSA alone does not mean the thing will lope either. The smallest 305/350 factory roller cam is on a 109 LSA. The 305/350 marine cam is also on a 109 LSA. Both are very tame.
 

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Did you get a Chinese map sensor? The map sensor from mercruiser is like 130 bucks. Also on my injectors there is no sealing at the intake port. They require a seemingly healthy amount of pressure to “pop” them into the rail, but when I put the loaded rail onto the intake they all are just loose at the intake port. I was expecting them to pop into place at the bottom as well creating a seal
 

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Did you get a Chinese map sensor? The map sensor from mercruiser is like 130 bucks. Also on my injectors there is no sealing at the intake port. They require a seemingly healthy amount of pressure to “pop” them into the rail, but when I put the loaded rail onto the intake they all are just loose at the intake port. I was expecting them to pop into place at the bottom as well creating a seal
I have had to replace the MAP. The MAP is a Bosch T-Bar and the genuine Bosch one is not very expensive. I will try to remember to get you the Bosch part number off the MAP.

Did you use fresh o'rings?
 
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