4.3L Vortec Marine Intake Conversion Helpfull Hints:

[xlv750laurent]

Hey Scott, thanks a lot for your great post and work.
Did you remove the pictures you were showing before? I don't see them anymore.
FYI I'm making the same mod on my 97 Blazer.
Thanks again
Laurent (France)

[FullThrottleV6]

[Ahbee]

Yeah bummer... getting ready to start my truck up shortly with this marine conversion... and I realized I need to replumb my coolant lines. I wish the photos were available on this thread. Any ideas on if they can be obtained anywhere?

[Aeromech]

Hi everyone, new guy here. I read all through this thread and decided I need to do the marine intake swap on my 2004 GMC Sierra 1500 with a 4.3v6. My recent searches come up with complete manifold assemblies, but are labelled as 2007 or newer. Are there different variations of the marine manifold?
Example linked below:
https://www.ebay.com/itm/142832330832

Will that assembly work on my truck? I'm not looking to add a turbo or supercharger at this time, just need better mileage and reliability.

Thanks for your help.
John

[Aeromech]

I ended up with the same intake manifold and ended up modifying an LS2 4 bolt to 3 bolt adapter to make it work. Has the channel machined for the idle air control valve machined into it and comes with a gasket too.

[Carbon Cruncher]

Hi guys
Thanks for all of the Information on the Marine manifold swap. I am drilling out the Thermostat bypass on mine right now! I hope some of you guys are still around if I have any questions regarding the swap and running boost on the old 4.3. It does not look too bad of a job and will post a pic or two when its completed. Thanks again

[airbrush guy]

Hi all . I'm in the Uk and have managed to get all the components and complete the conversion of a 95cpi astro to marine intake and although its been running I'm still wondering if I'm on the right track with tuning and injector values etc, its running the stock bosch marine inj and have fpr at 43.5 so should be 24lbhr. I originally used the stock tune and adjusted the flow rate which was ok ish and have since tried many variants of tune and inj voltage offset values and even tracked an original mercruiser tune file and adapted it to run on the $0D tune and then logged and adjusted ve values , but would appreciated if someone wouldn't mind have a look over it for me and any advice would be appreciated. I've asked around with tuners etc over here but they all just give me that crazy look and say "you've done what pffttt" lol

Thanks guysmarine inj and ve.jpgspark table marine.jpg

[UR50SLO]

I am still around... I do not have time to lurk on the boards anymore.
I do have most of the pictures on my laptop now.
I can try to edit the post to help folks out.
If you need anything [email protected] is still my current E-Mail.

Cheers guys!

I just finished my wife's 92 GMC Typhoon.
We will be on Sick Week down in Florida with her Typhoon and my 7 Second Camaro.
(same event as Hot Rod Drag Week)