As seen in Speedboat Magazine’s November 2019 Issue.
Headers for 454
I have a 27′ Checkmate with a 454 Magnum MPI. Currently, the exhaust is stock MerCruiser cast iron manifolds and risers. The boat is also equipped with the Corsa Captain’s Call switchable system that diverts the exhaust through the propeller hub when activated. I need to keep the ability to silence the engine. I was planning on doing some upgrades to the engine soon with a more aggressive camshaft profile that is similar to what is used in the Mercury Racing 525EFI.
I have been told that my stock exhaust system will hinder performance and their use may result in exhaust water reversion with the increased cam duration.
I was considering the CMI part number 13186, but l need to know if they can be installed in conjunction with my current Captain’s Call system. If not, what system will work?
Damian Zapata Odessa, TX
As seen in Speedboat Magazine’s September 2019 Issue.
Props for Formula
I have a 2006 Formula 382 FasTech running twin Mercury Racing 600SCis with Bravo XR drives. The current propellers are 30-pitch lab finished Mercury Racing Bravo One 4-blades. I am looking for a mid-range cruise performance increase with a prop change. The boat currently runs 60 mph at 4000 rpm. WOT is 5,100 to 5,200 rpm at 82-84 mph. What diameter and pitch would you recommend in a Mercury Racing lab finished Maximus 5-blade propeller? Is there a long wait for a set of Maximus lab finished propellers?
I am looking to purchase immediately because my boating season is somewhat short.
Thanks for your time!
Patrick Owen, Henderson, NY
As seen in Speedboat Magazine’s August 2019 Issue.
Oil Pump Issues
I have a Schiada V-drive with a carbureted turbocharged 540 cubic inch big block Chevy coupled to a Turbo 400 transmission. Recently, I noticed erratic oil pres-sure and now it is very low, especially at idle. The motor has a solid roller cam, so I don’t hear any lifter noise, and seems to run OK, but I am afraid to run it. The oil pressure gauge is mechanical, so I think the low pressure readings are accurate. Can you give me any ideas of what the problem might be?
Jason Miller Parker, AZ