Looking for a Whipple for 5.7 Vortec

[L31MaxExpress]

I had a crossram marine intake, 80mm throttle body and a 4" intake on my 350. The 4" air intake system added 20 hp at peak and 30 hp at redline compared to the stock air intake alone. Pictures comparing the stock air intake vs what I put together using a 4" dryer elbow from Home Depot and 4" silicone intake elbows. Used a $40 2007 Corvette LS7 MAF in a $30 Spectre 4" housing and a $20 MAF screen to get a 100mm MAF for under $100. Tuning required for the MAF but the Lingenfelter 100mm MAF table was very close close starting point.

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[L31MaxExpress]

This is what I am going to be running for a manifold and throttle body now on the 383. I was running the intake manifold already with an elbow and LS throttle body but decided on an even bigger TB. I like the idea of the progressive secondary throttle blade opening though. I milled 1" out of the plenum divider so hopefully the low rise manifold I am stuck with has a chance of breathing well. Unfortunately I had to go with the lower profile plenum that is 2.25" tall rather than the taller 3.5" version. In retrospect I should just put a 3" body lift on the damn van so I can run a single plane intake and 3.5" plenum but really don't want to go through that headache. Would also give me the extra inch of clearance I need for a cheap carb style nitrous plate.

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[Awest623]

Heads up, I stumbled on a marine intake. Asking price looks a little high, especially with the visible corrosion in the thermostat hole and on some of the bolt holes. But these don't pop up often, hopefully you can talk him down a little.
https://www.ebay.com/itm/GM-Intake-...41963a9ae:g:ZIMAAOSwMN5d2gAM&autorefresh=true
(If you don't want it, I might take a shot)

 

[L31MaxExpress]

Heads up, I stumbled on a marine intake. Asking price looks a little high, especially with the visible corrosion in the thermostat hole and on some of the bolt holes. But these don't pop up often, hopefully you can talk him down a little.
https://www.ebay.com/itm/GM-Intake-...41963a9ae:g:ZIMAAOSwMN5d2gAM&autorefresh=true
(If you don't want it, I might take a shot)

Just a warning. That does have a 4 bolt throttle body. From what I remember it is not the LS 4-bolt pattern. Those had a marine specific 4 bolt DBW throttle body similar to the last of the old 4.3 trucks.

The base is cast iron. Even sitting on a shelf they will surface rust over time.

 

[Awest623]

Just a warning. That does have a 4 bolt throttle body. From what I remember it is not the LS 4-bolt pattern. Those had a marine specific 4 bolt DBW throttle body similar to the last of the old 4.3 trucks.

The base is cast iron. Even sitting on a shelf they will surface rust over time.

Ahh ****. Didn't notice it had a different throttle body pattern, that's a shame.

 

[L31MaxExpress]

Ahh ****. Didn't notice it had a different throttle body pattern, that's a shame.

Nothing that a person could not fabricate an adapter plate for.

 

[L31MaxExpress]

My vote is still for heads, cam and a single plane intake on that 383.

With a 5.13 rear gear and stock V6 4l80E converter my naturally aspirated 383 pulled a 6,200 lbs brick to an 8.48 @ 79 mph in the 1/8. It was not a dead hook either. It was spinning the LT265/75R16s a bit. Ran a 2.15s 60' time. With drag radials it would have cut a sub 2.0s 60' and knocked atleast a couple of tenths off the ET. That is in the ballpark of 500 hp. I was pulling 410 gms/sec of airflow at peak with the smaller 218/228 cam. Horsepower is roughly equal to Mass Airflow in gms/sec multiplied by 1.2. A power robbing 2nd gear dyno was 387 at the wheels through the 4L85E and 10.5" 14-bolt.

ETec200 heads, a 232/244 Lunati Bootlegger cam, Rhoads V-Max lifters adjusted at .014" cold, 1.5:1 roller rockers, a single plane intake and 4" air intake along with decent headers and exhaust would put the HT383 close to 500 hp at 6,000 rpm and have near stock idle quality. With the Rhoads lifters it would have a very flat torque curve and make around 500 ft/lbs at 3,500 rpm too.

Aluminum heads will knock 50 lbs off the front end too and allow for a more aggressive timing advance curve. The timing advance increase helps counter act the larger intake port in low-end torque. The rhoads lifters help counter act the low-end and driveability loss of the bigger cam. Now that I have run the combination myself I will never go back. Its the best of both worlds literally. Like getting the power of a 170cc intake port and small cam on the bottom end and the power of a 200cc head and bigger cam on the top-end. With the idle and fuel mileage of the small headport and cam cruising down the highway.

I bet I knock 3 tenths off my 1/8 mile time with the bigger cam, the larger throttle body and the new converter. 8.20s from a NA L31 based 1-ton Express conversion van will be absolutely hauling ass for what it is. 8.20 1/8 in that brick is roughly a 13 second flat 1/4 mile. The few times it has been on a 1/4 mile track it ran 1.59x the 1/8 mile time in the 1/4. When it had the 350, I went from a stock time of 17.8 to a 15.6 and it still ran the same 1.59x the 1/8 mile time. With drag radials and a day with mineshaft air (negative DA, once raced my Ram in -1,600ft DA!) I am sure I could run a 12.5 in the 1/4.

 

[Awest623]

Sorry for the thread hijack Hutchinson, just one more question.

Nothing that a person could not fabricate an adapter plate for.

Are the upper half of the marine manifolds aluminum or steel?

 

[L31MaxExpress]

Sorry for the thread hijack Hutchinson, just one more question.



Are the upper half of the marine manifolds aluminum or steel?

The ones I have had are aluminum.

 

[Awest623]

The ones I have had are aluminum.

Thanks

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