L31MaxExpress
I'm Awesome
A late model 454 or Marine TBI unit can be bored to 54mm. The 54mm flows 750 cfm.
https://www.ebay.com/itm/54mm-7-4L-...109199?hash=item3656a8600f:g:zlMAAOxyqUpQ70Jf
I have tuned the MEFI computer on a hopped up TBI marine engine. Was stroked to 396 cubes. Aluminum vortec heads. 218/224 comp marine cam. The log style manifolds were changed out for marine water jacketed cast headers. Exhaust was modified with a corsa captains call setup that can be switched to above hull outlets with the flip of a switch rather than being forced through the lower unit and prop. The prop on the bravo drive had to go up 3 pitches from the 320 hp TBI 350 that was in it. 19' boat went from 55 mph to just under 70 mph on a GPS. Went from the 350 turning 4,800 rpm to the 396 turning ~5,200 rpm. The stock 2" bore 350 TBI unit was retained but the injectors were swapped from the 46 lb/hr injectors to the 61 lb/hr units. The marine regulator runs at 30 psi. The 46s flowed 74 lb/hr. The 61s flowed 104 lb/hr. While the owner did add a high performance flame arrestor that breathes better the rest of the induction was straight off the 320 hp 350 Mercruiser. The 320 hp 350 was a Corvette aluminum head engine with the 395' marine cam. Intake manifold was a mercruiser rebranded performer rpm.
https://www.ebay.com/itm/54mm-7-4L-...109199?hash=item3656a8600f:g:zlMAAOxyqUpQ70Jf
I have tuned the MEFI computer on a hopped up TBI marine engine. Was stroked to 396 cubes. Aluminum vortec heads. 218/224 comp marine cam. The log style manifolds were changed out for marine water jacketed cast headers. Exhaust was modified with a corsa captains call setup that can be switched to above hull outlets with the flip of a switch rather than being forced through the lower unit and prop. The prop on the bravo drive had to go up 3 pitches from the 320 hp TBI 350 that was in it. 19' boat went from 55 mph to just under 70 mph on a GPS. Went from the 350 turning 4,800 rpm to the 396 turning ~5,200 rpm. The stock 2" bore 350 TBI unit was retained but the injectors were swapped from the 46 lb/hr injectors to the 61 lb/hr units. The marine regulator runs at 30 psi. The 46s flowed 74 lb/hr. The 61s flowed 104 lb/hr. While the owner did add a high performance flame arrestor that breathes better the rest of the induction was straight off the 320 hp 350 Mercruiser. The 320 hp 350 was a Corvette aluminum head engine with the 395' marine cam. Intake manifold was a mercruiser rebranded performer rpm.
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