bad news.. need a new motor. Help me plan the new one :)

[270win]

For the money, I'd have a good machine shop do a 383 rebuild...stroker crank kits are cheap. Comp Cams can put you on the money with a cam grind. You can use them, but you don't need Vortec heads...If you get them you'll need a reverse flow water pump and guide plates for the push rods and a Vortect compatible intake. A mild marine cam will be fine lift wise on the Vortec's if you decide to go that route. Either way, I'd have a good carb builder rebuild your Q-jet to be compatible to whatever combination you choose. The Q-jets are smoother and more fuel efficient than the Holleys IMO and once they're right, they are much more consistent..The key is finding someone that KNOWS them thoroughly. I can hook you up with a Q-jet guru if you're interested.

At the end of the day, a 25 AJ just isn't going to "perform" without some serious HP or a BBC with a B III drive. When it comes time to re-power, I'll be putting in a stock 454/330HP Merc with a B III.

 

[Bandit]

I'll have to check the cam specs and get back with you but it was a mild Crane marine grind. The motor was originaly put in front of a Cobra drive in a 26 ft Bayliner Sunbridge (6000 pounds) with no problems, just now going into the 240 Hardtop with an MC drive so no data yet for you. I was able to reprop the Cobra and get better planeing speeds and more top end. I had a machine shop do all the bottom end work (put the 400 crank in a 350 block and install pistons, rods, brgs) and I assembled the rest. 5 years ago the cost was slightly over 2000.00 for their work and parts (I supplied the block, cam and heads). Total I have approx. 2700.00 in the motor but that was using some parts I already had (heads) and my own time. I beleive I had about 150.00 in cam, 200.00 intake, 150.00 gaskets. Machine shop/engine builder estimated the HP at about 320 to 330 and I know that I'll have to be easy on the drive with that but it is not a hot rod boat and should be OK if I behave myself, if not I switch over to something a little stronger later on.

Hopefully I'll have the transom back together later this month and start putting the motor in so if my luck holds out I may have some more info in a couple of months.

Yea it sounds about what i was figuring on spending. Did you use stock heads or vortec heads? Oh jeez did you have to do your transom over too?

 

[Bandit]

For the money, I'd have a good machine shop do a 383 rebuild...stroker crank kits are cheap. Comp Cams can put you on the money with a cam grind. You can use them, but you don't need Vortec heads...If you get them you'll need a reverse flow water pump and guide plates for the push rods and a Vortect compatible intake. A mild marine cam will be fine lift wise on the Vortec's if you decide to go that route. Either way, I'd have a good carb builder rebuild your Q-jet to be compatible to whatever combination you choose. The Q-jets are smoother and more fuel efficient than the Holleys IMO and once they're right, they are much more consistent..The key is finding someone that KNOWS them thoroughly. I can hook you up with a Q-jet guru if you're interested.

At the end of the day, a 25 AJ just isn't going to "perform" without some serious HP or a BBC with a B III drive. When it comes time to re-power, I'll be putting in a stock 454/330HP Merc with a B III.

Im figuring if I was not going to do the vortec heads I wouldn't do the stroker either and just do the stock rebuild. Typically you can find vortec heads pretty cheap.

There's a guy named Hobbs up here who is good with them. I do need a line on a good engine builder in the area though (new england).

I'm not ruling anything out here, but you've been looking into the big block swap, what is the realistic cost starting from scratch? I don't need anything crazy for performance but if I could cruise over 30mph and top out over 40 id be pumped.

 

[270win]

Im figuring if I was not going to do the vortec heads I wouldn't do the stroker either and just do the stock rebuild. Typically you can find vortec heads pretty cheap.

There's a guy named Hobbs up here who is good with them. I do need a line on a good engine builder in the area though (new england).

I'm not ruling anything out here, but you've been looking into the big block swap, what is the realistic cost starting from scratch? I don't need anything crazy for performance but if I could cruise over 30mph and top out over 40 id be pumped.

Vortec heads are easy to find, but there are many many different Vortec heads so you have to know the casting numbers that you want.

Personally, I've estimated the cost to do a 454/B III conversion to $10K...remember, these rebuilds usually cost twice as much as you estimate and take twice as long to accomplish. I doubt that will get you a 30 mph cruise as the best cruising RPM is 3000, 40 mph would be tops I would think. But the boat would have much better response and stay on plane at lower RPM settings.

Check out Cagerattler's thread on his restoration of a 255 AJ. He ended up with a 496/Bravo setup and got some impressive numbers from his boat...not a cheap swap though.

 

[Bandit]

Vortec heads are easy to find, but there are many many different Vortec heads so you have to know the casting numbers that you want.

Personally, I've estimated the cost to do a 454/B III conversion to $10K...remember, these rebuilds usually cost twice as much as you estimate and take twice as long to accomplish. I doubt that will get you a 30 mph cruise as the best cruising RPM is 3000, 40 mph would be tops I would think. But the boat would have much better response and stay on plane at lower RPM settings.

Check out Cagerattler's thread on his restoration of a 255 AJ. He ended up with a 496/Bravo setup and got some impressive numbers from his boat...not a cheap swap though.

True I have noticed the differences in the heads. has anyone on here had any luck with any particular Vortec head?

I know my hull is very similar but it is 2 feet narrower than the amberjack as I have it's little brother the SRV 250. Might not make a difference, but that might make somewhat of a difference in cruising rpms. She never ran right for me so cant say with certainty.

I do love the boat but it's a tough pill to swallow putting 10K into her when saving for a house. 3Kish for a stroker sounds more like my budget.

 

[270win]

True I have noticed the differences in the heads. has anyone on here had any luck with any particular Vortec head?

I know my hull is very similar but it is 2 feet narrower than the amberjack as I have it's little brother the SRV 250. Might not make a difference, but that might make somewhat of a difference in cruising rpms. She never ran right for me so cant say with certainty.

I do love the boat but it's a tough pill to swallow putting 10K into her when saving for a house. 3Kish for a stroker sounds more like my budget.

I ran the 1996 LT1 modeled Vortec heads on a 355 in my 72 Nova and got 400hp/400ft.lbs tq. with a mild hyd. roller cam (.460/.460 .292/.292 on a 112 LSA) Performer RPM intake and long tube headers. And the best thing about these 1.5/1.95 valved heads is that they are cheap and they produce really strong low end torque, 3000 rpm was the torque peak and the 112 LSA cam had a relatively flat torque curve...I would not recommend this as a marine setup, but it shows the potential. It also says to me that Alpha drive killing low end torque is possible with these Vortec heads without stroking the motor. If you plan to buy these from a junk yard and have them redone, be forewarned that some ¾- and 1-ton trucks came with Vortec heads equipped with a specially hardened exhaust seat that kills low and mid-lift flow. Casting number 10239906 should be avoided period!

I didn't realize that you didn't have an AJ, you're correct, you have a different animal to work with. It should make a big difference in what's required to power it. The cruising rpms wouldn't change, if it's carbureted, 3000 rpms is the highest rpms attainable without starting to open the secondaries on the Q-jet. The question is, what will make the best hp/tq at 3000 rpms for the buck to make the most sense for your boat and budget...personally, saving for a house, I'd just rebuild what you have and go enjoy my boat. JMO. If re building now is your only choice, I'd buy a long block setup, put the old intake/tin parts on her and let it ride. I'd bet that with all the miscellaneous things you come across to replace in the course of the rebuild you'll be pushing $3K easy. Depends on how much you do yourself really. I would think that if you start stroking the motor or changing heads etc you'll blow $3K and beyond wide open.

I'm already looking for my 454 and any Bravo setups I can come across in anticipation of the engine swap to come for my AJ.

One question, other than a low compression check, does your motor use oil, knock, run rough/miss etc? You know there are a lot of guys that run their motors with one or two weak cylinders for YEARS with no major failures...just a thought.

 

[CV-23]

In other news looking into it more 400's don't work for marine applications due to siamese bores. So I'll probably be doing a 383. The good news about alpha 1's is i can get a brandy new one from SEI for like 1500 if she does blow!

trust me I'd love to get a speedier boat, but the waters I boat in get extremely choppy so I like my deep V hull. A little extra speed would be nice though!

Not sure that's true....the 502 has siamese bores and work fine in the water, Mike.

 

[Flat Rate]

Yea it sounds about what i was figuring on spending. Did you use stock heads or vortec heads? Oh jeez did you have to do your transom over too?

I used stock Vortec heads off from a 1996 Chevy Tahoe that I had done a motor swap on for a guy and I think they have a 64cc combustion chamber. The machine shop used a 383 stroker kit (crank and pistons) and then had to machine a slight amount off the tops off the pistons to keep me at the 9.1 compression so I can run regular gas. The heads were cleaned up and normal valve job done on them but nothing special, I bought a cast iron intake manifold for it and rejetted the carb a bit richer and I also installed a Delco EST distributer kit (from Michiagn Motorz). New cam and normal engine rebuild stuff like gaskets, freeze plugs and bearings but nothing hi-tech. Best thing about this setup was that I was able to reuse all the other parts off the original engine (exhaust manifolds, fuel pump, oil pan, rocker covers, flywheel, starter, alternator, drive hub). It went right in and fired up and had no issue's with wiring, coolant hose's or power steering lines, looks just like the stock motor, idles smooth, makes great torque and the fuel ecomomy seems a slight bit better. Overall I am really happy with it and that is the reason that I am now swapping it into the SeaRay.

Michigan Motorz did offer a 383 stroker motor when I did mine and that was what I had intended on doing but because of some of the parts I had and people I knew I went this route instead and I do not regret it. A normal rebuild on your stock motor would probably make a big difference in how your boat performs but if you are looking for a bit more HP/Torque with out changing a lot of other parts then the stroker is a good way to go. Either way you are going to have some money and time involved and you are the best judge as to what you think is best for your boat.

And yes I am redoing the transom in the SeaRay, it was a decent boat but had some wood rot in the transom and needed a lot of TLC (don't they all). I got the boat from my uncle who didn't think it was worth keeping around or fixing so my son and I took this project on and plan on making it a salmon fishing machine to replace our bigger boats. Wood has been removed and in the process of putting it back together over the next couple of months. This has been a real learning experience but it is also fun and interesting to be able to make this boat the way we want it and not a compromise between a family boat and a fishing boat.

 

[Bandit]

...

 

[Bandit]

I used stock Vortec heads off from a 1996 Chevy Tahoe that I had done a motor swap on for a guy and I think they have a 64cc combustion chamber. The machine shop used a 383 stroker kit (crank and pistons) and then had to machine a slight amount off the tops off the pistons to keep me at the 9.1 compression so I can run regular gas. The heads were cleaned up and normal valve job done on them but nothing special, I bought a cast iron intake manifold for it and rejetted the carb a bit richer and I also installed a Delco EST distributer kit (from Michiagn Motorz). New cam and normal engine rebuild stuff like gaskets, freeze plugs and bearings but nothing hi-tech. Best thing about this setup was that I was able to reuse all the other parts off the original engine (exhaust manifolds, fuel pump, oil pan, rocker covers, flywheel, starter, alternator, drive hub). It went right in and fired up and had no issue's with wiring, coolant hose's or power steering lines, looks just like the stock motor, idles smooth, makes great torque and the fuel ecomomy seems a slight bit better. Overall I am really happy with it and that is the reason that I am now swapping it into the SeaRay.

Michigan Motorz did offer a 383 stroker motor when I did mine and that was what I had intended on doing but because of some of the parts I had and people I knew I went this route instead and I do not regret it. A normal rebuild on your stock motor would probably make a big difference in how your boat performs but if you are looking for a bit more HP/Torque with out changing a lot of other parts then the stroker is a good way to go. Either way you are going to have some money and time involved and you are the best judge as to what you think is best for your boat.

And yes I am redoing the transom in the SeaRay, it was a decent boat but had some wood rot in the transom and needed a lot of TLC (don't they all). I got the boat from my uncle who didn't think it was worth keeping around or fixing so my son and I took this project on and plan on making it a salmon fishing machine to replace our bigger boats. Wood has been removed and in the process of putting it back together over the next couple of months. This has been a real learning experience but it is also fun and interesting to be able to make this boat the way we want it and not a compromise between a family boat and a fishing boat.

Yea it sure sounds like a nice setup. One question did you have the machine shop use your origonal block or did you grab another one? My boat's always been a saltwater boat so I'm a little leary about having them stroke that.

 

[Flat Rate]

Yea it sure sounds like a nice setup. One question did you have the machine shop use your origonal block or did you grab another one? My boat's always been a saltwater boat so I'm a little leary about having them stroke that.

I used a different block, my original engine still ran and I wanted it as a spare if things didn't work as planned.

 

[270win]

My boat's always been a saltwater boat....

If you're using the boat offshore, scratch what I said about riding it out as an option. Going offshore is no joke, and I'd never go out with a known issue like that.

 

[Ididntdoit]

I do need a line on a good engine builder in the area though (new england).

Go to Eastwood's in Somers Ct. or R&L in New Hampshire - Stay away from precision in simsbury and R.A.D. in Palmer

 

[Bandit]

...

 

[wvsundancer]

If you keep the Alpha I would make sure to stick with 300HP or below.. my 98 had the last of the carb. 350 mags and I blew a couple of props out of it. I was always worried about that drive. That being said a friend of mine had a bayliner with the old carb. 454 with an Alpha drive go figure bayliner). I don't see any real benefit going to 383 route. I think with a 350 carb. you can get 300HP with no problem.

 

[sdarc]

That is a good and cheapest way to replace your engine. 300 hp will only happen at the peak/ high revs. Big torque numbers down low may/could cause damage.

Flywheel will get changed to a 1pc. rear seal type. Don't know about the bellhousing but I don't see why it would need to be changed.

 

[sdarc]

Looking at the date of your boat it may already have a 1pc rear seal and correct flywheel. I know trhe cars changed then not sure if boats were still using the old blocks that was in inventory.

 

[270win]

No need to change to an electric pump, you will need a vortec intake, but your carb should bolt right up. Bell housing is the same, you need to check the rear main seal for the flywheel. Also, I think the 96 changes over to a roller cam so that will be a bit more expensive, but the benefits of a roller engine FAR outweigh the price on the cams.