LS Swap Seafari 25

[Xcomunic8d]

Guys,

I wasn’t sure if I should put this under my restore thread but I ultimately decided this way might be easier for others searching. My apologies if this bothers you, dear reader.

I’d like to thank and acknowledge all of you guys that have helped me LOTS. Strick, Blue Heron, Terry, Don V, and K Moose. Thank you and thanks to all of you that have encouraged and given input. Especially for the CG estimator! You guys are the best almost as good as our boats.

My seafari 25 was converted from twin I/O’s somewhere in its life to an Outboard. The deck space is just amazing. But the Outboard went DOA due to a flywheel. New Outboards are expensive and even heavier. When you do the math you will get better hp and handling and retain a purity that was the original boat.

So you will lose some deck space no 2 ways about it. I’m consoling myself with plans of a teak swim platform. My plans for my boat is serious offshore fishing for ono (wahoo), ahi (yellowfin tuna), and marlin.

Step 1 you need to locate a LS. I have a LMG 5.3 out of a Silverado 1500. I’ve known my friend for years so I know it’s history. I also got the engine for free.

After you locate your donor vehicle you will need to plan out your build. I HIGHLY recommend a closed cooling system in salt water environments. Also consider what outdrive you will use. I’ve heard of guys using 400hp on alpha drives. I’m finding awesome deals on Bravos. That’s a better option, IMO.

I’m looking for max hp on these but I can’t find one. In 73 these had up to 500+hp through twin mercruisers based on 351W block and as low as 330hp.

My goal is to build a 5.3 as close to 500 as I can on a reasonable budget. There are plenty of how to’s on pulling a Ls, so I won’t be labor that. I do want to suggest pulling the heads and undoing the bell housing bolts that way instead of removing driveshaft and unbolting the tranny. Saved me hours.







Here’s the oil leak I found. Look you will see the o-ring protruding from fill tube.








The engine is ready to pull today.

I will be deleting the VVT, Putting a new camshaft in, and a tuner (Holley terminator x?).

I’ll make a parts list and sources as I go. Wish me luck all.