Where to start with this engine rebuild?

Does switching from the stock fiberglass muffler on the GT40 to the Y pipe add any power or does it just enhance sound?

Seems complete, I have seen worse. I do not see anything that is scary. Most all can be rebuilt/reburb. Several good TBI rebuilders online too. Had my injectors rebuilt, calibrated mine flow equal and better than new. I personally would not buy old bon-yard parts until a machine shop confirms what you have is not repairable. Look over at Fordmuscle forums for lots of how-tos on all things Ford performance. Your engine is basically same as Ford Lightning 150 or other similar HP models. Good to start as original and an be a real beast with the right tweaks.

well, it has been a LONG couple of days, but the engine is in, and I put the boat in the water this morning for a shake down cruise! ... Pretty excited to have it start, idle and go.    It definitely needs a bit of adjustment,    I must have mis-adjusted the transmission shift cable, as the forward shift is a bit on the hard side, and comes in about 900rpm or so.   reverse feels super nice and comes in great.   I had 75PSI of oil pressure, and ran at about 175 for temp on the lake, so I feel pretty happy with where we are now.    definitely some lessons learned that I'll post later, but on the way to the lake today, I discovered some trailer braking issues that I need to go look at..    BTW,   my intake barely fits under the dog house, but it works, I think it is squishing the insulation just a hair, but that's something to worry about later.

Yes! Congratulations!

He guys, Sorry for the delayed response, we were away on vacation.     Unfortunately, we made it approximately 60 miles from the house before the truck cam shaft sensor decided it was done (Snoqualmie pass- For Kevin's benefit) and left us with a large tow bill and some really bummed out kids.     After being towed, we decided to salvage what was left of our vacation days and went to the ocean instead, sans boat.   So, no lake Chelan boating excursion for us this year, I guess we'll have to try again next summer.     The trailer brake issue was amazingly simple, I am not sure why someone had put 4 new backing plates and new shoes on the trailer, and failed to adjust them, but it sure made stopping a WHOLE lot nicer once they were all adjusted properly.   

For lessons learned on the engine rebuild/assembly:

- get a harmonic damper installing tool.    You can rent the puller at a local auto supply store, but the install tool will save your..... bacon.    I tried to put the balancer on with the bolt, and had to look for a new bolt for several hours on a holiday weekend.    It was expensive, and I had to buy the install tool anyway, so just buy it in the first place.     BTW, no impact wrench was involved in severly cross threading the bolt (1/4" of threads), it was all by hand, but I mis-interpreted the resistance as the pulley needing to go on, instead of the fact that I was crossed up.   once stuck, the cross thread was VERY difficult to remove.
- New ford blocks have an oil dip stick hole in the block, this is easily sealed by installing a "freeze plug" in the hole.    There are several hack methods, but since the soft plug is so readily available, and is a removable solution if the block needs to have a dipstick in the future, the choice seemed clear.   
- My Edelbrock RPM performer manifold with a 1" stock spacer and a standard spark arrestor fit fine under the dog house, YMMV, but it may work if your alignment puts the engine lower than about 1/2 way on the mounts. it is very tight though
- Great stuff comes in caulking style tubes, about half the size of a standard tube.   this is plenty of sealer if you end up doing everything with the same sealant.   I used most of the 1/2 size tube.   I did GS my oil pan, before reading the instructions that the sealer is only n eeded in the corners, but I read several varying opinions on whether or not to seal the silicone seal or not.   Time will tell, it does not leak yet, after almost an hour of run time.

- WINTERIZE....   yes, this is important, I would not have purchased this boat if I had known all the things that I would need to replace due to someones lack of attention to winterizing.     I had to do breakers, steering cable, engine, exhaust, bilge pump, shower, blower etc, as I think that the water got pretty high before it froze.    Over all, I have a much greater understanding for how these boats are put together, and a greater appreciation for how much they cost.   I've decided that the next one will probably not be a project

Dreaming, congrats on getting your boat up and going! I recently picked up a 1986 Mastercraft in VERY similar condition!

It has the 351w and was obviously watterlogged, same water line accross the flywheel like yours, and just like yours, the rear cylinders on each head are low compression....

I am guessing that when water get into the engine/intake, that it just naturally takes the path to the back cylinders? you did mention that your intake was cracked.

looking at mine, none of my freeze plugs are blown, so maybe it didnt freeze as badly as yours did, did you ever figure out how the water ended up into the rear cylinders? assuming it was just from sitting and not being covered/winterized for a long time.

I really appreciate any response, I am basically going through the same thing with my new to me boat.

here is my thread: http://www.mastercraft.com/teamtalk/showthread.php?t=80060&page=3

my compression numbers look like this:

right head:
1: 100
2: 177 (carbon buildup or something?)
3: 123
4: 78 (wet 92)

Left Head:
5: 112
6: 116
7: 117
8: 62 (wet 105)

I agree with Mr McD on start it and run it.

After reading your M/C thread and your post here, I'm not sure why you think you have any kind of internal water issue in the engine. It sounds like you're assuming you have/had water in #4 and 8 because there's low compression, but nothing I read makes me think there's water there. A few years of sitting with water in those 2 cylinders and the engine probably wouldn't turn over at all.

I think before trying to start it though, I'd take the valve covers off and look at #2 exhaust valve rocker arm and pushrod and compare it to the others. With compression that much above the others you may have a bent pushrod, loose rocker arm, or a collapsed lifter.(we won't mention anything worse like bad cam lobes) I think it's worth a look beforehand.

How's your transmission fluid look? Depending on how high the water got, it may have water in it.

And one other thing..............remember it's a Mastercraft with a NORMAL rotation engine and a firing order of 1 3 7 2 6 5 4 8 if you start getting advice from people used to Reverse rotation engines

Ditto... These guys are a great help, and have been throughout my project.   Mine had bad water damage, the core/casting/freeze {;)] plugs were out of mine when I bought it, and were laying in the bottom of the boat.    the manifolds on both sides were also cracked and needed attention.    the intake had been full of water, as the throttle body plates were rusted shut, it was bad news.    I coudl not rotate the engine when I bought the boat, I had to fill it with marvel mystery oil and let it sit for a few days before it broke loose.    the reason for my engine overhaul was that the compression was good on 6 of the cyls, but the other 2 were so much lower that the boat had a bad stumble and would barely run when under load.   idle in the driveway on the hose was just fine :) best of luck with your project, I am still working out the bugs, but each step makes me feel like I accomplished something!

jieiku wrote: Thanks guys, mostly posted here because Dreaming had low compression in the rear cylinders on a boat that sat and had standing water in it, seemed so similar to mine. I appreciate the responses. and yeah the boat has a heater core and heater vents, so I picked up new fuel lines for the fuel tank, and heater core hose for the heater. Will try firing it up and running it soon! Also thank you for the comment on the valve cover and #2 rockers/pushrod. I will definitely do that before trying to start it! appreciate it.

Stick around here (CCF) too and keep the info and questions coming. It's an inboard, who cares what brand it is