Time to chuck the 470

[flashback]

I would swap in an entire 5.7/A1G2 into the boat

If my recently acquired searay 22 is any indication of weight vs power, I agree..my boat is heavy compared to the 21ft CC I had. The CC was 1000 lbs lighter with basically the same engine. Like a Camaro compared to a Cadillac But once upon plane
it is smooth.

 

[Lou C]

I was shocked when I weighed my '88 Four Winns. On the trailer it was 5050 lbs, the trailer is about 850. That's 4200 lbs for a 20'9" long boat. With a deep vee hull design and a 21* deadrise it does cut through the chop we always seem have here.

 

[Scott06]

Yeah. For sure. Scott, I got a bit of stick from some guys on here for it last time, but my very close friend (told this story loads previously) had a darragh 22ft boat with a 3.7 in her. Was a cruiser thing…all be it, a fairly light built one, but certainly heavier than most any 18/19ft open boat of the usual type. Long story short, he had issues with the original engine. Found out the previous owner did too. The usual issues of course. Mended them as best we could…new pump and head work etc etc. then that gave in too with the usual issue after these things give out. Ended up with another good but used 3.7 in her. Similar issues within a year or so. He wasn’t the type that wanted to mess with things like constantly tinkering with an engine, like these things need. So he just ended up putting a brand new 3.0 in her. Mated to the same pre alpha drive. Actually used the same 17” black max prop too. The 3.0 did just a fine job to be fair on it. There was a little lack in grunt to get on plane, compared to the old 3.7 (when it did work)…but if you hadn’t experienced the old engine, you’d not be complaining about the 3.0 and the job it did. As for the top speed…if you didn’t have a gps Speedo and monitoring it closely, you wouldn’t notice the difference top end. Was only about 1 or 2 mph slower. The boat seemed much lighter too. If he wanted to mess for perfection, he might have tried another prop…but it did just fine.

No disputing the durability and reliability of a 3.0, had one in a 17 ft sea ray for many years and really beat the snot out of it taking the kids tubing and skiing. Propped correctly it can give decent performance and you are correct that it may be an easier swap. Not a bad suggestion depending on how deep the OP wants to get into it.

 

[teardropty]

Nola Mike's 3.7/470 --> 4.3L swap thread

I'm sure that this will be a saga, so starting a new thread. Just picked up an '89 Glastron donor with a 4.3. I'm planning on refurbing the engine and adding a 4bbl carb and vortec heads. I'm going to start on the engine in a bit, and then swap it in the fall after the season. 1st question...

forums.iboats.com

Also, where are you located?

Nashville, TN

 

[teardropty]

Here is a 4.3 install drawing https://samerwebapp01apncus01.azure...phawithtwo-pieceexhaustmanifold_1996-2001.pdf

Here is a 5.7 drawing https://samerwebapp01apncus01.azure...41bb-90c9-f0958ee21906/57lalpha_1996-2001.pdf

biggest issue you will have to negotiate is the engine compartment width and length. Being inline may need to widen fir a V engine.

other big one will be the side motor mount stringers usually some built up blocks of wood glassed in.

theres a lot of other details but id start here. Bottom line if the boat has value to you it helps justify the effort and cost.

The stringer/width issue shouldn't be a problem. The rear area of the hull is a blank slate.

 

[teardropty]

Wow the responses have been great! My biggest issue with the 3.7 is finding parts at a more reasonable price/availability. I am no stranger to engine work (mainly in the auto world) having rebuilt numerous pre-96 Fords and GMs. The 4.3 appeals to me because I have a good Alpha 1 Gen 1 outdrive that has been rebuilt. My understanding (and I could be wrong) is that a 3.0L would require a change in the outdrive and/or prop whereas a 4.3L wouldn't require a change. Is that correct?

 

[QBhoy]

Wow the responses have been great! My biggest issue with the 3.7 is finding parts at a more reasonable price/availability. I am no stranger to engine work (mainly in the auto world) having rebuilt numerous pre-96 Fords and GMs. The 4.3 appeals to me because I have a good Alpha 1 Gen 1 outdrive that has been rebuilt. My understanding (and I could be wrong) is that a 3.0L would require a change in the outdrive and/or prop whereas a 4.3L wouldn't require a change. Is that correct?

No change in outdr Be required at all. Hope that helps. But if you go 4.3….everything but the outdrive needs changed. Inner transom set up too, for exhausts change. You’ll know about thr invasive glass work you’ll need too. For the mounts.

 

[nola mike]

No change in outdr Be required at all. Hope that helps. But if you go 4.3….everything but the outdrive needs changed. Inner transom set up too, for exhausts change. You’ll know about thr invasive glass work you’ll need too. For the mounts.

Not true. A change in power in either direction would/might require a different ratio drive or prop. No need to mess with transom plate unless moving to an a1g2 setup.

 

[Lou C]

Just compare the ratios used in each engine. There was a list of these floating around a while back….

 

[QBhoy]

Not true. A change in power in either direction would/might require a different ratio drive or prop. No need to mess with transom plate unless moving to an a1g2 setup.

Wouldn’t need a change in ratio at all. Certain of it. That’s what he asked there. Prop pitch an inch or 2 at worst.
Regards to the inner transom area. He would be lacking an exhaust pipe for a start…going to a 4.3 . But the big issue is the intrusive glass work needed to the inner hull for the mounts. If I was to be going to that extent of involvement…I’d be weighing up the effort and cost versus it’s worth

 

[Scott Danforth]

I personally wouldnt want a 3.0 liter in a 2100# 19 foot boat. it wasnt a stellar performer in a 1500# 16.5 foot boat

going thru the effort to swap out a 470, I would definately drop a 4.3 or larger into the boat

 

[Scott06]

To the OP since this boat has family value to you and you want to do it right, you best bet is to find a boat (cl/ebay) with a '91 and newer (gen 2 drive) preferably 96 and newer (for vortec engine) that has a roached interior or rotten stringers. Even if block is cracked (get new or reman longblock) you will have all the bits and pieces (wye pipe, manifolds, wiring etc) to do the swap pulleys to prop, an you could update to the current drive.
You really could do a 4.3/5.0/or 5.7 . I did a 4.3 =>5.0 swap was pretty easy.

 

[QBhoy]

To the OP since this boat has family value to you and you want to do it right, you best bet is to find a boat (cl/ebay) with a '91 and newer (gen 2 drive) preferably 96 and newer (for vortec engine) that has a roached interior or rotten stringers. Even if block is cracked (get new or reman longblock) you will have all the bits and pieces (wye pipe, manifolds, wiring etc) to do the swap pulleys to prop, an you could update to the current drive.
You really could do a 4.3/5.0/or 5.7 . I did a 4.3 =>5.0 swap was pretty easy.

Is the 4.3 to 5.0 maybe easier because you don’t been to change the engine mounts patterns? Or did you ?

 

[Scott06]

Is the 4.3 to 5.0 maybe easier because you don’t been to change the engine mounts patterns? Or did you ?

I didn't because my boat was set up for it (boat was factory offered w 4.3's and 5.0's). Stringers supporting side mounts were long enough to accommodate the 4.5" diff between 4.3 and 5.0 locations and front and back of blocks are identical between 4.3 and SBC. I just plugged the original lag screw holes and drilled new ones in once engine was aligned.

Even if the OP has to glass in blocks for side mounts that is relatively easy. What would be a deal breaker for me would be if engine compartment an rear seats had to be moved then I would stick with a 3.0. I've seen newer Merc and VP 3.0's with side mounts -I'm assuming that boat manufactures got sick of making hulls with both front mounts and side mounts for 3.0/4.3 boats.

 

[Lou C]

If the OP wants to do a 4.3, the way I'd do it is go with a 96 and newer Vortec, with a 4bbl carb for sure. That will give approx 225 hp, maybe a little more with an Edelbrock intake. However, if the boat is heavy for its size like mine is, the 5.7 is easy to justify, the cost is about the same really, its just a question of whether you have enough room for the extra length of the V8. However, the V8 is really not much longer than either of the 4 cyls. Its the width and engine mount issues that have to be worked out.
The one other thing in favor of the 4.3 is somewhat better fuel economy, I've always been surprised how little fuel mine uses, probably because of the small primaries of the 4bbl Quadrajet.

 

[Scott06]

The one other thing in favor of the 4.3 is somewhat better fuel economy, I've always been surprised how little fuel mine uses, probably because of the small primaries of the 4bbl Quadrajet.

you are not going fast enough ...

 

[QBhoy]

I didn't because my boat was set up for it (boat was factory offered w 4.3's and 5.0's). Stringers supporting side mounts were long enough to accommodate the 4.5" diff between 4.3 and 5.0 locations and front and back of blocks are identical between 4.3 and SBC. I just plugged the original lag screw holes and drilled new ones in once engine was aligned.

Even if the OP has to glass in blocks for side mounts that is relatively easy. What would be a deal breaker for me would be if engine compartment an rear seats had to be moved then I would stick with a 3.0. I've seen newer Merc and VP 3.0's with side mounts -I'm assuming that boat manufactures got sick of making hulls with both front mounts and side mounts for 3.0/4.3 boats.

Fair comment Scott. I get you.

 

[Lou C]

you are not going fast enough ...

True. Most of the time water conditions here aren’t smooth enough for WOT!

 

[QBhoy]

If the OP wants to do a 4.3, the way I'd do it is go with a 96 and newer Vortec, with a 4bbl carb for sure. That will give approx 225 hp, maybe a little more with an Edelbrock intake. However, if the boat is heavy for its size like mine is, the 5.7 is easy to justify, the cost is about the same really, its just a question of whether you have enough room for the extra length of the V8. However, the V8 is really not much longer than either of the 4 cyls. Its the width and engine mount issues that have to be worked out.
The one other thing in favor of the 4.3 is somewhat better fuel economy, I've always been surprised how little fuel mine uses, probably because of the small primaries of the 4bbl Quadrajet.

I thought my 4.3’s were very good on fuel too. I’d imagine back in the day when a 4.3 producing 205hp in VP Aq205a form…was only a little short on power compared to the v8 AQ211…it would be possibly even preferable to that ?

 

[teardropty]

You guys are a wealth of knowledge. I do appreciate it. Also, not sure why nola_mike swap thread didn't pop up when I did my initial search before asking in this thread. THAT is a vast amount of knowledge! So thanks.

NOW unto my current situation..... I had a long time customer come by the shop today and looked at the boat. During the conversation I mentioned issues with the 470 and mentioned a 4.3 (that is my leaning) but then he said he "thinks" he might have a good 3.0L sitting in his barn and if so I could have it for nothing. Like I said before I am not necessarily needing speed over reliability, so the 3.0 would probably do ok for me. I already have a 69 Mustang with a 460 for speed needs. Other than the gear ratio issue and prop change, anything else that would have to be done to swap from the 470 to 3.0? Thanks.