Trojan Boat Forum

Repowering our '77 F30 running 1989 non Vortec 5.7L GM that were purchase used and installed about 12 years ago - not rebuildable.
Considering new longblocks - Qjet carbs rebuilt and new distributors, new flexplate, existing fresh water cooling system, starters, alternators, etc.
rebuild BW 1:1 trans with 14-11 props
Or new Vortec base engines with Holley carbs?
Comments and critique greatly appreciated!

Vortec with roller cam and good carb would be a good choice. You'll need to change flywheel and bell housing. But block foot print is same.

as Jamie said it would be a good choice, but I would use a Holley or a Q-jet I'd with a Edlebrock marine carb. Then my 2nd choice would be a Q-jet. Use Holley's on my Chevelle and hated the thing would never stay set and the power valve set up suck's..

What Marina our you off the Pank, I have a FedEx Ground up there. Are at the end of Cobbs Creek Rd. ?

Also heard the vortec runs cooler.
Roller cam is good advantage - I'll make sure that's in the package.
Didn't know about the bellhousing - thought the only bolt up difference was at the intake manifold to the vortec heads.
Preference is to the Q-jets, but if intakes are changed out for vortec, I'll look at Edelbrock. Heard some issues with the marine Holleys and am not familiar with them - I am though with Q-jets from '67-72 Chevy small block fun days.

On the Piankatank at Cobbs Creek, Ginney Point Marina since 1995.
Thanks for the info Guys.

I don't believe the bell housing is different . If your old engines have 1 piece rear main seals then the fly wheel will be the same . the one piece rear mains stared in 86 .

Any recommendations on suppliers?
MichiganMotorz??
I can drive down to BasicPower in NC and save freight.

If you're buying new, why not buy fuel injection and electronic ignition? My last boat had a Volvo 5.7 GSi, and it ran great with very little maintenance. I know Crusader offers a 5.7 with fuel injection and electronic ignition. I'm sure other manufacturers also offer them.

My 30' Sea Raider is powered with twin 350 Vortec's with TBI and electronic ignition. Mine are Mercs and were dyno'ed at 330hp. Didn't like the TBI at first, thought it was too complicated being an old school type.....however, I've come to appreciate the injection. Trouble free and instant starts hot or cold.....assume the fuel consumption might be a little better too........no points, no carb.....no problems.......so far................John

Anyone know how they set up the O-2 sensor on the marine fuel injection wet exhaust? Just curious. Thinking of converting my chryslers to fuel injection.

The Dog House wrote:If you're buying new, why not buy fuel injection and electronic ignition? My last boat had a Volvo 5.7 GSi, and it ran great with very little maintenance. I know Crusader offers a 5.7 with fuel injection and electronic ignition. I'm sure other manufacturers also offer them.

Boy, I was just thinking the same thing. I often thought of repowering my
tri fly with fuel injected engines when I had her. My biggest concern was the galvanized tanks and the little grit like particles that would fill up the fuel filters. My thinking was the particles would wreek havoc on the injectors. Disclosure: I am not a mechanic, it is just an assumption.

hello - i know its a ways from you but i use marine engines in holliston ma they have new 350 gm 1997 and up vortec roller engines with 8 bolt intakes @325 HP for 2710.00 i think they come with some tin like valve covers -oil pan timing cover- rh rotation is 3499.00 they have just about everything you could be looking for and if for nothing else you can compare prices. they stock a lot of stuff and have complete packages.like i said check out the web site for info at least good luck

I saw Ship Shape TV show a little while ago and they were doing a repower with an engine marinizer in Louisiana. I do not remember the name of the company, but you could check the show's web site. The company looked pretty good on the show. They said their prices were better than most...

davidsmith wrote:Anyone know how they set up the O-2 sensor on the marine fuel injection wet exhaust? Just curious. Thinking of converting my chryslers to fuel injection.

Doesn't apply unless you're talking about the new catalytic applications. The sensors are typically mounted; one pre catalyst just above the manifold, the other sensor is mounted after the catalyst in the elbow.

vortec big advantages are in the heads with high flow ports and fast burn combustion chambers. you can use the vortec heads on an old block best used with flat top pistons and ends up at about 9.4:1 compression make sure you use an external bypass for the coolant because the older heads use a hole drilled in the head for coolant bypass. limit your ign timing to 28 degrees max, and use a rail style rocker arm stock or better yet a roller tip from comp cams

older mpi vortecs 2001 - 2010 use a mapped fuel sytem where the calibration is flashed, mapped or burned and cant be changed easily