possible engine upgrade

[captmello]

Re: possible engine upgrade

It looks like a 280T, A 280 with hydraulic trim. Walts advice is good. grab the spare parts and go from there.

 

[Bondo]

Re: possible engine upgrade

Here's where a 383 would be a great improvement. I believe most of the marine part't will bolt right up manifolds etc...Wait for Bondo's reply..Now why a 383 you would be effectivley doubling the horsepower and tourqe of that old 305..and more than probably the same econ....On big question would be will the drive survive that much power..Nice boat

Ayuh,.... I'm goin' with captmellow,... Do a compression test, 'n see what the 305's got left in her,....

1600 hours is but maybe 1/2 way through it's expected life cycle,...

Plenty of time to come up with a 383 reman long block with vortec heads, 'n d-dish pistons,.... :joyous:

The dressin's off the 305 will bolt right on, but the intake manifold('cause of the head swap)....

Ya may as well run the 305 til she pukes, 'n Then long block it,....
just start savin' for that brand new HT-383 now,....

 

[Walt T]

Re: possible engine upgrade

I agree. For a little more money though you can buy a lot more torque and HP with the stroker. He has a pretty heavy boat, that's why the 383 keeps coming up. He really should have a big block in that but that is beyond most budgets. The stock 5.7 does have more torque and HP than the 5.0, but not always. A boat his size needs more than a 'maybe'.

 

[DJ87]

Re: possible engine upgrade

Thanks for all the great ideas. I'm leaning to the 383 concept and will be passing on the aq260. I just googled remanufactured 383 and found a nice one from summit racing for $2600 but it isn't a marine block . I won't be doing a lot of salt water but will be keeping her at the lake in a covered slip . What are your thoughts on nonmarine blocks with all of my 305 parts on it? As far a weight Walt you are right, she isn't a fly bridge Victoria but still heavy . Dry weight is 4900 lbs and I have added fridge , TV , small geny , gear, 3 batteries and it has a 100 gallon fuel cell

 

[billbayliner]

Re: possible engine upgrade

Find yourself a good 1.95:1 Duo Prop lower unit.
Go through the proper shimming procedure when installing it, and your 5.0L will think and act like a strong 5.7L!

Your 5.0L with a DP (propped correctly) will outperform a 5.7L with the 280 s/p drive.


Quoting a buddy of mine who knows the SBC.

Many of the 6.3L (383) builds today will be using the GM style full dished piston. It's particularly important with the 383 build that this piston not be used, in lieu of a quench style piston.
Most any good machine shop will know which piston selection to make for a Marine 6.3L build.

If closed system cooled, the Marine head gaskets are not necessary.

 

[Scott Danforth]

Re: possible engine upgrade

you can have your local quality machine shop build you a 383 cheeper than you can buy one from summit.

also, for a non-marine block, switch out the core plugs to brass, the head gasket to marine friendly, and the cam to marine friendly and you now have a marine block.

switch over all the marine electrics and stuff and you have a marine motor.

 

[billbayliner]

Re: possible engine upgrade

BTW, the one photo is showing an old 280 PT drive.

The "T" drive is quite different.

 

[Walt T]

Re: possible engine upgrade

Its pretty simple to make an automotive long block a marine long block but it's a job for a mechanic. Most blocks come standard with brass freeze plugs so that's covered. Head gaskets need to be marine though and that means removing the heads and then readjusting all the rockers. I suggest calling Summit and ask about marine head gaskets or a marine version of the stroker. If you have the builder install them then the warranty stays intact. I've done this a few times for friends on standard motors but the thing is, if the motor throws a rod then the builder can try to claim it was whoever changed the head gaskets fault, and the guy who did the head gaskets will say that's not possible and guess who is holding the bag. Summit has a nice marine stroker but it'll run ya 4 grand.

 

[billbayliner]

Re: possible engine upgrade

Walt, Ive spoken many times with a friend regarding the marine version SBC.
In order to take an automotive SBC and turn it into a decent Marine cruiser engine, the full dished pistons need to go!
These have no place in a SBC for Marine use.... yet GM and many rebuilders continue to use them!

These will need to be changed to a quench style piston, (or a single valve relief flat top piston) and used w/ 76cc chambers (5.7L *3.480" stroke only)!
Quench target will be .038" or so!

Or ..... use a LCQ piston w/ 64cc chambers.*

If there's no quench area, *you just won't be able to make good torque.

And again, if the engine is fitted with a close cooling system, there is no need for the Marine head gasket set! *A high quality automotive gasket with the correct compressed thickness is necessary for the quench dimension any way!

 

[Walt T]

Re: possible engine upgrade

Seen dished, flats, valve relief pistons in all sorts of marine engines over the years and they all ran fine. Not everyone is looking for performance, and most boat owners don't care whats inside of the engine as long as it does what they want. Not all auto engines are dished. Sure a lot of the older GenIs are, but not all. Vortecs are a good example of flat pistons made for that quench. Builders use dished pistons because they don't know what kind of fuel will be used and they have to warranty the engine. If you want to tear down a new engine and build it the way you want go right ahead. Most of the guys here would rather have the warranty provided by the builder. You can look at the specifications provided on the engines on the Summit site, most of those 383s are called dished, but are flat with reliefs. Those give excellent quench. Your friend is assuming other builders don't know what they're doing. Take a look at the torque specs, these builders know whats what. Of course neither myself or your friend has seen the inside of those motors so who knows. All I know is never assume anything.
Yes, closed cooling systems don't require marine head gaskets but I like them anyway, they're just heavier duty. Not everyone has closed cooling and it's expensive to install. We have to recommend marine. As I said he's not looking for performance, just wants a better cruise. You are spot on with your gear ratio and the 5.0s. 5.0s outperforming the 5.7s... perhaps. Perhaps not. I've seen a lot and sometimes I've sworn up and down about what will outperform what and been proven wrong. One really doesn't know until the hull actually meets the water. Good advice on the drive ratio though.

 

[Tail_Gunner]

Re: possible engine upgrade

Walt, Ive spoken many times with a friend regarding the marine version SBC.
In order to take an automotive SBC and turn it into a decent Marine cruiser engine, the full dished pistons need to go!
These have no place in a SBC for Marine use.... yet GM and many rebuilders continue to use them!

These will need to be changed to a quench style piston, (or a single valve relief flat top piston) and used w/ 76cc chambers (5.7L *3.480" stroke only)!
Quench target will be .038" or so!

Or ..... use a LCQ piston w/ 64cc chambers.*

If there's no quench area, *you just won't be able to make good torque.

And again, if the engine is fitted with a close cooling system, there is no need for the Marine head gasket set! *A high quality automotive gasket with the correct compressed thickness is necessary for the quench dimension any way!

I know you mean well and there is some merit to what you are saying. But actually unless your building a very high dollar and extremely well built engine.....Its a empty argument...almost no merit to this conversation what so ever. Now that is not a statement on you nor your engine builder.....Well maybe your builder....maybe a lot on the builder.

 

[billbayliner]

Re: possible engine upgrade

Walt, some of this is copy-past from my buddy. He has posted on this topic many times.

The later GM Marine version SBC (w/ 64cc chambers) will typically use the Full Dished pistons. There is no quench surface with this piston..... Vortec cylinder heads or not.

The piston's dish volume simply controls Static C/R.

The double valve relief full dished piston (1 part number) fits all 8 bores.

The double valve relief F/Ts require only 1 part number.
The single valve relief F/Ts requires 2 part numbers.

F/Ts are capable of creating a quench area when the piston deck dimension and compressed head gasket thickness are correct..... but with a 5.7L 3.480" stroke, 76cc chambers must be used. (64cc chambers would make for an excessive static C/R).

A true LC Q style piston requires 4 part numbers for a SBC.

Neither GM nor the average re-rebuilder wants to deal with multiple part number pistons and the fitting onto the connecting rods.

And you are correct ...... the average boat owner doesn't know the difference nor does he care! But this owner is leaving some performance and fuel economy behind and on the table.

And BTW, no one is suggesting that we buy a new or remanufactured engine, and then change out the pistons and-or head gaskets. That would be very counterproductive!
For a good quench built Marine Cruiser SBC, we need to custom build it from scratch. The cost to do this is Peanuts...., relatively speaking

As for a warrantee..... the only change required would be the piston profile and compressed head gasket thickness. This should not affect any warranty if the builder is worth his salt!
In fact, there's much less risk of detonation damage with a properly built SBC.

GM's 377 cu in SBC (the standard 4.000" bore version for Marine) uses GM's full dished pistons. This piston does not offer a full quench surface, it only offers a partial fat top landing. This does not create a squish or quench area!

If you are familiar with MichiganMotors, they recognize and see the advantage in building a "quench effect", and will do so via a custom order basis.

Any good automotive or marine machine shop can do this build, and it won't break the bank.

It's all about making a good LPCP if we want torque from our SBC Marine engine.
A lazy LPCP holds back performance that would otherwise be available.

If we can't see the advantage of the SBC Q/E for Marine cruiser use, then we haven't done our research.

 

[Scott Danforth]

Re: possible engine upgrade

opcorn:

I guess my current 350 with 3.48" stroke is running flat tops with 4 valve reliefs, vortec heads with 64cc chambers (that actually measured closer to 62cc shouldnt be running on the local pump swill that Im feeding it.

Im going to side with Walt and Tail_Gunner

 

[Bondo]

Re: possible engine upgrade

opcorn:

I guess my current 350 with 3.48" stroke is running flat tops with 4 valve reliefs, vortec heads with 64cc chambers (that actually measured closer to 62cc shouldnt be running on the local pump swill that Im feeding it.

Im going to side with Walt and Tail_Gunner

Ayuh,.... I'm not gonna side with anybody, as the OP is lookin' to buy a block, 'n not Build a block,....

IF, yer gonna build a block, Bill is Dead on Right,...

I know who he's talkin' 'bout, 'n the ideas are Rock Solid, as to buildin' the Most Efficient, Most Detonation free long block possible,...

IF yer buildin' a long block, you can use d-dish pistons, tighten up the quench, 'n put to Full use the Vortec design head chambers,...
With d-dish pistons, 'n a quench of 'bout .040, you can run 'bout up to 10:1 compression ratio, Without Detonation,...
The Ultimate Torque Monster,....

IF yer buildin' a long block, it's these little Tricks, that separate the Custom motors, from the usual crate motors,...

Just as backyard Mechanics have been tweakin' the SBC since 1955, there's Always room for improvement over the usual standard production runs,...

 

[billbayliner]

Re: possible engine upgrade

Bondo, right.... that would be Ricardo.
If anyone is interested, he has done a short write-up in this thread starting at post #7.

V6 to V8 engine swap

 

[Tail_Gunner]

Re: possible engine upgrade

Yes Quench has its place and a big place...er small actually have a read

GrumpysPerformance.com • View topic - quench & squish

Quench is NOT affected by the volume of a dome/dish/valve relief or the head combustion chamber size. Only the distance from the top of the piston (flat portion) to the bottom of the head affects quench. The quench effect will vary depending on how much ?€œquench area?€? there is on your setup, but that will be discussed later. Here is a picture to illustrate what quench is (piston deck clearance + compressed gasket thickness is your quench).
Image

 

[Bondo]

Re: possible engine upgrade

Quench is NOT affected by the volume of a dome/dish/valve relief or the head combustion chamber size.

Ayuh,... Yer Right,....

Bill, 'n I are only pointin' out that by choosin' the Right pistons, the quench area can be Maximized for the Best results from Vortec heads,...

 

[Walt T]

Re: possible engine upgrade

Yep. Guys like us who build our own engines can do this stuff. Other fellas can take all this information to a builder if they like. I like mine, flat tops, with camel humps now. Got Vortecs at machine shop. Still trying to decide what cam profile I should use. However Mr. DJ87 doesn't really care about dishes and quenches, maybe quiches and wenches. I don't discuss stuff like that with owners who may be a Lawyer or Doctor or accountant, as it's just greek to them just as the Law or how to do a penile implant would be to me. I see Bills point and it is indeed a good one but why get worked up? I for one would rather Mr. DJ87 have an easy and good experience with any upgrades and / or including the drive mods. Bill is right, I do agree DPs would be awesome. Maybe more cost effective than engines. Give it a shot with DPs, then if still not happy well the DPs can easily take a quiche and wench 383. Its fun spending his money. Not sure I'd do any of it, I'd probably just stay with the 5.0s and when the time comes decide then. Who knows, 10 years from now the wench starts looking a little bedraggled and it's time for a new younger model wench.

 

[Walt T]

Re: possible engine upgrade

I've read Mr. Ricardos Posts, he knows of what he speaks. Just like a lot of fellas here who understand it all has to work together. Custom builds are nice... If that's what the customer wants. True it doesn't cost that much more to use 'correct' pistons but it does indeed cost more. Cam profile figures into this entire equation along with intake and exhaust which all add up. It's pointless to build an engine 'correctly' as Mr. Ricardo states if we are gonna still use the stock intake and exhaust. Wet exhaust limits cam profile which limits the true output of a truly well built engine. Customer will love the torque though, can't argue with that. The problem really comes at top end which is what the customer is really looking for. We know better, but the customer doesn't. For a standard deep V hull which most guys have Mr. Ricardos motors would give awesome 'Pull' and may turn a higher pitch prop so top end will be a little better. But the customer is disappointed because he had 10-15 mph top end in his head. After all he spent a lot of money, got lectured on quench, and was under the impression this would be awesome. And it is. To US. Why spend more when the base V hull, wet exhaust, cam profile, possibly intake, all are stock? A true performance boat has pretty much none of these. The average person just wants a solid performer, a good cruise, and runs on pump gas with turn key starts, never have to change the oil or ever have to lift the engine hatch ever again. And they want it all at a fair price. Dish, quench, it's all meaningless. I build for what a customer wants, I do not lecture customers on what they should want. Then I, as all builders, warranty the hell out of that puppy. Why put more pressure on the rods and crank if it's not needed? Why build an expensive base engine that is going to be choked anyway? Just MHO, not dissing Mr. Ricardo or Bill.

 

[billbayliner]

Re: possible engine upgrade

Walt, here is the same thread but with an update for you. This may shed some new light on the topic for you.
See the recent posting.

V6 to V8 engine swap

'