2 questions; accessory brackets; thru hull exhaust

212rowboat212rowboat Posts: 2,247Member ✭✭✭✭✭
I'm repowering... Lost out on the 383, but have a 5.7 lined up.  It's a complete 2005 drop in... 280HP as it sits, but it will be outfitted w/ some 1.65:1 rocker rollers I've got laying around (if they clear the VC's)... also, a cast dual plane square bore intake manifold w/ 700cfm holley, and that will likely push it to around 290 maybe 295 ttl.. perfect for my purposes. 

I don't know if I need the accessories, but it's going to hinge on the brackets and accessories themselves.  I know that a 4.3 shares a lot with a 350, from internal bore and pistons, rods, lifters- basically it IS a 350 with two missing cylinders...

so my question#1 is:  "will the accessory brackets from a 4.3 match up to the 5.7 casting?"

next up, is thru hull exhaust... I've got a bead on a corsa captains choice set up for this thing, or, another brand (can't recall the brand name) that has vacuum actuated cut-off's, which make more sense to me- either for same price... these include tips... 

so my question #2 is: "is thru-hull exhaust worth it?" ...

it's cutting two 4" holes in my transom... if it's worth it I'll do it- doesn't look hard at all, and it will sound great- but there are more concerns above 'sound' when you're talking cutting through a transom, potentially weakening it... 



  • jme097jme097 Algonac, MIPosts: 1,218Member ✭✭✭
    If you can do the side of the hull I feel like (for me personally) it would be less nerving. I would do anything to avoid transom rot if at all possible. Besides with the chrome exhaust bezels for the side hull it would definitely look better just my 2 cents.

    Boat Name: Knot A Worry
    2007 280 Rinker Express 6.2L B3
  • 212rowboat212rowboat Posts: 2,247Member ✭✭✭✭✭
    i've got one of those huge swim platforms on my rig, and can conceivably run the exhaust above the waterline just below that platform... I'll have to look to make certain...
  • Handymans342Handymans342 Posts: 7,454Member ✭✭✭✭✭
    A couple of chrome stacks would look nice  :)
  • Michael TMichael T Posts: 6,558Member ✭✭✭✭✭
    edited February 2016
    @212 you have the perfect set-up for through hull s EXACTLY as you have surmised. There is plenty of room where you indicate you might go. The Rinker transom /hull area is IMO the strongest in this class of boats by FAR! You will be astounded by the quality of the layup when you cut the holes out.  I did my first through hulls in 1994 using Corsa electronic actuators (I really dislike the air actuated units as they are a PITA,  IMO). This was done by putting a 383 into a Rinker 190. The Corsa came ready to go.  I needed some high performance wet exhaust hose and some tips. I chose Gil off shore composite tips with internal flappers.  I ran wiring to a switch on the dash and later added a light to signal when it was on as if I left it on with the boat on my lift the batteries were dead fast due th the high amperage solenoids. Started on a Friday morning at about 8:30 and was finished by 3:30.  It took longer LOL because I measured for  the friggin' holes about 20 times before we cut! BEST THING I EVER DID FOR OUR JUST PURE FUN! The engine gained over 100 RPM ran about 5 degrees cooler in normal conditions BUT the oil temp remained much cooler longer when at WOT on lengthier runs. As for the cool factor EVERYONE loved it, even the Admiral. Sooooo -  easy to do,  good for the engine and AWESOME for fun. Something,  IMO,  that you would never regret. BTW,  just my opinion,  but I had side through hull exhausts in my 2011 Rinker 226 XL with 350 Magnums.  They took up too much room in the engine bay. Good luck  Drew! 
    Post edited by Michael T on
  • Michael TMichael T Posts: 6,558Member ✭✭✭✭✭
    Whisky Tango Foxtrot -  what happened  did I just get cloned or am I seeing double from too much Caribbean sun? Steve, you'll never keep up with two of ME.  LOL
  • Dream_InnDream_Inn Annapolis, MDPosts: 5,250Member, Moderator mod

    MT, I think you are just seeing double??  LOL  :)

    I love cars/trucks with noise (the right rumble), but for some reason never got into it in boats.  (it actually bothers me, sorry for adding my opinion. I guess if you go with a thru hull, respect those in marinas and nice quiet anchorages :) )

    Dream 'Inn III -- 2008 400 Express

  • 212rowboat212rowboat Posts: 2,247Member ✭✭✭✭✭
    we agree on that, DI... obnoxious, is the term I would use... I wouldn't do it w/o having the ability to divert it... now what I'd like to have is a partial either way type switch... but... want in one hand, right?

    that said- it's hella better than choking it up the way it runs through the drive now... and, it will keep the drive cooler, as well...  I'm looking at mufflers as I type this- and will have one selected soon I hope.. 
  • Handymans342Handymans342 Posts: 7,454Member ✭✭✭✭✭
    Time to come home MT !!!
  • frodo13056frodo13056 Channahon, ILPosts: 212Member ✭✭✭
    I had a 1990 236 with the Corsa stainless exhaust with the solenoid actuated polished stainless diverters. Not only did it look great, it sounded very cool with the 454 big block. I had that Rinker for 5 years and the only issue I had was the solenoids fried - but it was a quick fix by calling Corsa and getting new parts.

    I also had a 1994 236 (454 also) with the Mercury Marine air actuated cast iron exhaust diverter - didn't look nearly as cool but still sounded great.
    The 236's that came with the exhaust diverters had the thru the side outlets and not thru the transom. The exhaust hoses were run pretty much up against the transom so they really didn't take up a ton of space in the engine compartment.

    This was the 1990 236 I never took any pictures of the engine comparment:

    This is the 1994 236 with the Mercury Marine air actuated diverters:

    This is the 1994 236 side exhaust:

    As for the question about the 4.3 / 5.7 accessory brackets - well, the 4.3 was a 5.7 engine minus 2 cylinders, so I would guess that everything should bolt up. Of course there may be differences in engine years but you might get lucky and everything will fit.

    What are your plans for propping the boat once the engine is swapped?

  • AlswaggAlswagg Posts: 2,418Member ✭✭✭✭✭
    Are you talking a vortec or prevortec?  If you have a prevortec 4.3 and a Vortec 5.7 you will need an electric fuel pump plus intake manifold hardware is different.   Oh you will need an appropriate dipstick tube.  
  • AlswaggAlswagg Posts: 2,418Member ✭✭✭✭✭
    I have numerous swaps like what you are doing    You will need v8 motor mounts.  Yes they are different 
  • 212rowboat212rowboat Posts: 2,247Member ✭✭✭✭✭
    edited February 2016
    thanks, Al et All (how often does one get to type that?) :smile:  

    so... I just can't leave ANYTHING alone, and love to blaze trails... and... this is no different... but first:

    Al, I currently have 8 bolt vortec's, and dry joint center risers- and the one intended for swap has same- I've offered him, and we'll see what he does... it is a complete engine drop in turn key including accessory bracket, accessories and fully wired... It looks to be a simple matter of swapping, and maybe three or four hours at my buddies shop (who works on boats for a living- he just pulled one off the bottom Monday morning, and I'll have to wait for it to clear the bay, but that is all i'll have to wait for)... I was looking for a negotiating tool and was going to say to him "well, knock off the cost of the accessories and brackets, and I'll take it for $X less".... but, I may just scoop it up and sell my current engine turn key... 


    I'm going to go through the sides with the exhaust, and it will be full time thru's... but with a twist... because I can't see why this won't work.... allow me a customary preamble: :smile: 

    exhaust theory is something I've always found fascinating... I've done every config you can imagine- on land... I've never messed with it on a boat... but engines are engines, and this holds true.... true dual rocks- but is inferior to an H or X pipe'd exhaust, which always has a hot pulse to maintain conveyors of pulses throughout the system... it promotes scavenging, which is very good always, in conflict with back pressure, which is very bad always...

    so... that is where I started the thought process... I want to X pipe the exhaust... 

    and I've done this before on a big block Mopar, using hooker long tube headers with a custom bend nearing where most would find a Y pipe... I cut the collector plate off both headers, and welded an X where the joined... then later, I cut them again, took the X out, and ran wedge pipes in front of the rear tires- I used a magna flow high flow true x muffler- it was a muffler of the perforated variety (whoosh at high RPM, not rumble like a chambered)... this... brings.. me.. to... this- and this is definitely blazing a trail, here... 

    off the back of the risers, instead of shooting straight out the transom or bending down toward the thru-top exhaust passage, I'm strongly considering mounting a true x muffler just like the one I've used before- stainless magnaflow true x... laying it at an angle, effectively lowering it's exit, and bending again toward the transom, bending yet again just enough in front of the engine rooms aft vents, and penetrating the side just below the cleats.  

    the X muffler and all piping will be wrapped (keeps heat in is it's purpose, but insulates engine room from heat is a nice side effect, too)... with the muffler, the sound is manageable... if it isn't, I shoot enough straight tube to introduce another muffler.... 

    this will sound SWEET, and it will eliminate any solenoids either electric or air- and less moving parts... 

    Post edited by raybo3 on
  • AlswaggAlswagg Posts: 2,418Member ✭✭✭✭✭
    You have a 4" X muffler?  Remember to use proper clamps and hoses.  
  • 212rowboat212rowboat Posts: 2,247Member ✭✭✭✭✭
    yup... they can be had in 4" i/o...  
  • AlswaggAlswagg Posts: 2,418Member ✭✭✭✭✭
    Cool take some photos  water evacuation is important.  It should work though
  • Glassguy54Glassguy54 Posts: 524Member ✭✭✭
    PLEASE make a comprehensive photo documentation and post here. This sounds like a fascinating project that I am sure would be of great interest to many on this forum!
  • 212rowboat212rowboat Posts: 2,247Member ✭✭✭✭✭
    the builder accepted my offer... Engine is inbound. 
    I'l be more than happy to document the build. 
    I may start pulling the drive tomorrow, as I've got a bellow kit that's been laying around for over a year.. 
    I wonder how much more load will be on the engine without the exhaust aerating (cavitating) the prop in those first few seconds?  

    So... for other users here with alpha1gen2 drives: if you're prop shopping for hole shot and low planing speeds w/o much impact on top end, I have a Ron Hill Marine Pleasure Five in s/s 19 average pitch, and 14 1/8" (or it may be 14 1/4") that is possibly up for sell or trade.. I'm thinking I'll be twirling a 22p this year, and wish like hades I hadn't sold that precision turbo2 in 22p 14 1/4" s/s to some dude on the beach who chewed his up in an oyster bed not ten minutes before I sold it to him.... for $75... I only paid $50, so I don't feel too bad about it, but you guys know it was worth a LOT more than that... and they aren't easy to find, anymore. 
  • youstolemybeeryoustolemybeer St Charles Mo. Eagles LandingPosts: 246Member ✭✭✭
    Im not really into the hotrod scene so bear with me, 
    Instead of all the bends here and there to connect the manifolds at an X, Why not just have a straight pipe connect the manifolds together. and then out the sides. From a fabricating pov that would seem the easiest
  • AlswaggAlswagg Posts: 2,418Member ✭✭✭✭✭
    Through prop exhaust creates a beget ice pressure and will actually suck out the exhaust.   This only changes when a motor moves more than 1100 cfm on a alpha and 1200cfm on a Bravo.  This is from Merc    So until you move more air than that you are simply creating more noise.    Example the 525 SC motors require through hull if a person wants both through prop and through hull that would be best 
  • 212rowboat212rowboat Posts: 2,247Member ✭✭✭✭✭
    I'll be half that.... And I'd rather put effort and money elsewhere... 
  • Michael TMichael T Posts: 6,558Member ✭✭✭✭✭
    Ok Drew, now I'm confused (happens more and more these days!  LOL). What are you doing? A rebuild with no through hulls, through hulls?????
  • 212rowboat212rowboat Posts: 2,247Member ✭✭✭✭✭
    I'd already picked out tips, and plumbed the thru hulls with my cursor (meaning my amazon shopping cart is loaded), and then Al breaks with that information about flow and the Alpha (1200cfm before it starts to restrict)... and... I won't be anywhere near that..

    the engine being delivered is 280HP as is, with a 600cfm holley four barrel (one of the baby four barrels, single pump vacuum actuated)... I plan on installing some rocker rollers (not just tips) I have which I originally thought were 1.65, but are actually printed 1.55 (still some added lift, but the real advantage is reducing parasitic power loss as well as actually being consistent- stamped rockers are notoriously inconsistent)... Still- I won't be anywhere near 1k cfm...

    If I drop on a dual plane intake and a 750cfm double pumper, add the rocker rollers (I can't justify buying more; it will be either the ones I have or the stamped that come on the heads) the total air is still below 1k cfm..

    the only two things that will push that engine above the rate that Al mentions is a cam, and head work.  the head work on a vortec is silly- they flow great to around .450, but fall flat on their faces from .450-.500, and to break .500 you gotta either break out the grinder and shave clearance for the pushers, or, go all the way to the camshaft and bump it up some lift/duration- and still you may have to do some grinding so the rods clear the casting... conceivably, 1.65~1.7 can be introduced on the marine cams in the engine, but doing so will land you flat in the 'dead area' of the heads- between .450 and .500, where there is pretty much zero gains to be expected...

    the engine is designed by mercruiser to be balanced with the parts on it- and they do a good job from what I understand... when someone messes with one aspect of it, it throws the entire balance out of kilter... the rocker rollers near the OE ratio aren't going to hurt anything, as the engine was blueprinted to use 1.5 ratio... using close to that (the 1.55's I have are actually more like 1.52 in reality) are actually beneficial, as the OE stamped rockers vary as much as .5 FROM ONE INTAKE VALVE TO THE NEXT... the rocker rollers will actually put the engine closer to the specs merc had in mind in the first place...

    so... I'm seriously torn right now MT... I want the thru-hulls for the cool factor, but i want it to be a manageable sound level- which is apparently hard to do with products available and NOT introducing back pressure (which is what I accused the drive of doing prior to Al's information)..... I'm stuck... and will likely flip a coin... 
  • Handymans342Handymans342 Posts: 7,454Member ✭✭✭✭✭
    Drew, Harley riders don't care about sound. Go for it
  • 212rowboat212rowboat Posts: 2,247Member ✭✭✭✭✭
    handy, do you know what a sneeky pete is?  if not, it's a custom pool cue that is on par with any custom cue you can imagine, but it looks like a house cue... it's purpose is to provide the best tool for the shooter while keeping as low a profile as possible... I mean, some dude walks into the pool hall with a custom case and breaks out a shamrock, I'm going to be careful in a 3 out of 5 with that fella- he spent that much on a cue, he likely knows what he's doing... some dude walks in with a sneeky pete, my only advantage is that I saw him walk in with it and know it's not a house cue- and I know he's gonna try to hustle somebody... and I know that somebody ain't gonna be me. 

    I like the idea of keeping as low a profile as possible.  loud exhaust won't accomplish that.  I like the sound of tuned exhaust as much as the next guy, but all that noise does nothing but draw attention... that ain't what I'm about. 
  • Handymans342Handymans342 Posts: 7,454Member ✭✭✭✭✭
    Like a street sleeper?
  • Glassguy54Glassguy54 Posts: 524Member ✭✭✭
    Our 17 year old grand daughter who lives with us (long story) LOVES  the sound of the 350 MAG MPI firing up when we take our 246 out. I think she would be positively giddy if we had through hull, but at our age, we kind of prefer less shock and awe! 
  • Michael TMichael T Posts: 6,558Member ✭✭✭✭✭
    Your grand daughter would have loved the sound of my 383 firing up on my boat lift. THAT had a huge blats of raw power! The good news was the when the  Corsa Quick and Quiet was in the silent mode it muffled the sound a lot, well below legal noise statutes. But, when idling through no wake zones or even in a marina it just gave a low rumble. I never had one complaint or even a dirty look, EVER,  - I DID get a lot of thumbs-up and "what have you got in there comments". Let's remember the Corsa system was on a 383 not a 1600 HP race engine, so when it was switched to silent there was no big deal. On silent running it was a bit louder than through the hub as the solenoid driven circular "flappers" do not close completely so even when off there was a slight "note" to the exhaust which was still IMO really cool. However, when out on the river or bigger open stretches of water, the sound was awesome. I was stopped a hundred times by boaters to ask what I had and at least a dozen times by Police who loved it. One Policeman who had a go fast came to our place with some beers to take pictures of my install. He boated on our river. When he decided to install the Corsa, I helped him. My motto: "Don't harm others but life is short, so if you want to have some good clean fun go for it before it's too late - something I know a lot about!" :-)
  • 212rowboat212rowboat Posts: 2,247Member ✭✭✭✭✭
    bingo, Handy... 

    I love the sound, too, glass- but not enough to rattle my eardrums... constantly...

    MT- that police bit... it's not that i've anything to hide from them as I don't do illegal stuff or would ever dream of drinking and running the boat- but they LOVE pulling folks around here... there are no less than six different agencies that will pull you, w/ the worst being the USCG- and only because THAT is a federal ticket as opposed for the dude checking you out, primarily, for having at least legal fish on board. 
  • Handymans342Handymans342 Posts: 7,454Member ✭✭✭✭✭
    I had straight out exhaust on my 351s and they had the big round barrel muffler. Can you use those?
  • 212rowboat212rowboat Posts: 2,247Member ✭✭✭✭✭
    the reason I'm torn is this:

    with the engine out plugging the Y is easy- real easy... it isn't so easy with the engine installed.  so.. I gotta make this choice now- while I'm swapping- to avoid the cost of a system such as a captain's call... it would be full time through hull if I do it now and a sealed Y pipe...
    If I wait, I can do the captain's call (or similar selection system) as it uses the Y pipe, and simply introduces a fitting between the two systems... the cost is cheaper NOW to do a full time through hull... the cost will be greater later, not in effort but in cost of the diverting device....
    decisions decisions...   

Sign In or Register to comment.