Performance upgrade questions

[mybadford]

I read several threads about guys wanting to upgrade cam shafts and intakes and carbs. I haven't seen any that mention anything about going to a better flowing head other than a vortec head. I understand in the general purpose marine world that running a cylinder head that you can drop a tennis ball down the runners is not the way to go. I know there's some kind of factor with the velocity of the small port heads that create the torque. I see a lot of threads mentioning guys wanting to pick up rpms and speed both. Obviously running a cam that starts making power at 3,000 rpms is not the answer either if your wanting to pull a skier or have a heavy boat. Bottom line is it's about making more power and still have that low end grunt, correct?????? Is there a reason guys don't swap a aluminum head or cast iron other than a vortec that flows slightly better than a vortec onto a sbc? Hypothetically speaking what would be the negative effects of using this set up in a 2900lb dry weight boat and if you could change the set up what would you change and why?
small block chevrolet 5.0 and or 5.7 roller cam non vortec
comp cams #08-417-8
intake exhaust
DURATION 270 276
lobe lift .33 .335
valve lift 1.5 .495 .503
Duration @.50 218 224
Lobe Separation 112*
Intake centerline 110*
intake valve opens 25*BTDC closes 65*ABDC
exhaust valve opens 24*ATDC closes 72* BBDC

Holley carb 0-80551 600 cfm vacuum secondaries
Edelbrock intake 2601
AFR 180cc cylinder heads 2.02 intake valve 1.60 exhaust valve
CFM @ 28" H2O intake exhaust
valve lift .200 138 110
.300 198 158
.400 240 190
.500 260 207

I don't know what the flow ratings are on a stock volvo AQ231A exhaust manifolds are but I read any of the stock manifolds on any manufacturer isn't real good.

Why I ask all of this is because i am looking at a 1990 Baretta Phaser 230 open bow. It has a AQ231A but I'm not exactly sure what model the outdrive is. I know its a single prop. The boat has 223.5 hours on it and it's priced good. I'm a person that just can't leave something alone. With the set up I've listed above does anybody see a horrible negative effect? Probably first thing I would do before any parts change with the engine would be to somehow figure out how to put a thru hull exhaust. I'd hope that might free up a little restriction with the exhaust even though I'd still have the stock manifolds. I'm looking for opinions.

Thanks in advance

 

[Scott Danforth]

Re: Performance upgrade questions

the AQ231 is a 305 Chev V8. the 305, much like the 350 nin my AQ271C, will sake up greatly with a set of vortec heads and a decent cam. However if you really want to wake up the boat, build a 377 or 383 stroker for the boat.

the cam you are looking at is a bit on the extreme end, and may require thru-hull exhaust. Also, make sure that your block is a roller. just because the auto engines were roller does not mean that the marine engine you have is a roller.

AFR heads are a great head, however with limiting the RPM's to 5000, not sure they are worth the extra expense over a basic set of vortec's. (I just paid $400 for a pair) The main reason that most dont swap aluminum heads is that generally aluminum heads are paired with a closed cooling system. If you are in salt water, aluminum heads and a closed cooling system are a must. factory aluminum intakes are dual alloy units with bronze alloy in the areas that come in contact with the raw water used for cooling.

the drive will have a tag on the outside, either a 270, 280, or 290.

welcome to Iboats

 

[mybadford]

Re: Performance upgrade questions

the AQ231 is a 305 Chev V8. the 305, much like the 350 nin my AQ271C, will sake up greatly with a set of vortec heads and a decent cam. However if you really want to wake up the boat, build a 377 or 383 stroker for the boat.

the cam you are looking at is a bit on the extreme end, and may require thru-hull exhaust. Also, make sure that your block is a roller. just because the auto engines were roller does not mean that the marine engine you have is a roller.

AFR heads are a great head, however with limiting the RPM's to 5000, not sure they are worth the extra expense over a basic set of vortec's. (I just paid $400 for a pair) The main reason that most dont swap aluminum heads is that generally aluminum heads are paired with a closed cooling system. If you are in salt water, aluminum heads and a closed cooling system are a must. factory aluminum intakes are dual alloy units with bronze alloy in the areas that come in contact with the raw water used for cooling.

the drive will have a tag on the outside, either a 270, 280, or 290.

welcome to Iboats

Yeah I figured out the AQ231A is a 305. I was originally told it was a 350 before I went and looked at it and looked up the engine number just from what the flame arrester said. The boat has closed cooling system. It also has the center bolt valve covers but doesn't really mean it is a roller cam engine especially being a 1990. I have my finger crossed that it is though. If not, a 350+ would be worth putting more time and effort into. A 377 is a destroked 400 correct? Why not just do a 400 or 434? I actually have almost (no crank) a 434 rotating assembly sitting on a engine stand with nowhere to go. But the parts for it are a little more than what a 5500 rpm engine would need. I've read a couple times about what you have mentioned about the bronze in the intake. Since this boat has a closed cooling system the bronze isn't really nessecary is it?? What is the difference in the head gaskets for marine engines?

I didn't really see any tags so to speak on the outdrive but I think I remember seeing a decal that I thought said SX on it. When I was looking at it I was looking more for stress cracks and hull damage. From what I have read the Baretta or known for blistering and cracking. But this boat is pretty priestine. I'd have to find a good glass person to help with getting it to where I could put thru hull exhaust because the swim platform was molded with the boat hull and doesn't really have a flat vertical area to bring the tips through. Not a big fan of side exit exhaust but that might be a easier route.

I'm not opposed to the vortec heads and they are the better flowing of the production heads. I am just curious why people didn't didn't put just a little bit better flowing head on and why I haven't read of any using a aluminum head. The salt water reasoning makes sense. I live around fresh water.

 

[Bamaman1]

Re: Performance upgrade questions

A marine engine is just used differently than a car engine. The stress on the boat engine cruising @ 4500 rpm's is far greater than anything most pickup trucks will ever experience.

Boats require high torque, smooth idling, low rpm motors. All the porting, big cams and expensive intake manifolds/carbs are not cost effective, as most running is not in the high rpm range where those mods pay off. You certainly don't want a camshaft out of a 1968 Z-28 in your boat going lope, lope, lope at idle.

Like was said above, the best bang for any car based motor is cubic inches. If you will contact the help line at Comp Cams or Lunati Cams in Memphis, they have some camshafts that are ground specifically for marine use--with flat tappets. You could also go with a minimally larger carb.

My only personal experience with headers and thru the hull exhaust is with those damned Donzi's that wake us up on summer Saturday mornings. They could put a fiberglass muffler on them and not be such a nuisance.

Another issue is the horsepower capability of your outdrive. Big, big horsepower may cause outdrive problems. Some times it's easier to keep things simple.

 

[Scott Danforth]

Re: Performance upgrade questions

Yeah I figured out the AQ231A is a 305. I was originally told it was a 350 before I went and looked at it and looked up the engine number just from what the flame arrester said. The boat has closed cooling system. It also has the center bolt valve covers but doesn't really mean it is a roller cam engine especially being a 1990. I have my finger crossed that it is though. If not, a 350+ would be worth putting more time and effort into. A 377 is a destroked 400 correct? Why not just do a 400 or 434? I actually have almost (no crank) a 434 rotating assembly sitting on a engine stand with nowhere to go. But the parts for it are a little more than what a 5500 rpm engine would need. I've read a couple times about what you have mentioned about the bronze in the intake. Since this boat has a closed cooling system the bronze isn't really nessecary is it?? What is the difference in the head gaskets for marine engines?

I didn't really see any tags so to speak on the outdrive but I think I remember seeing a decal that I thought said SX on it. When I was looking at it I was looking more for stress cracks and hull damage. From what I have read the Baretta or known for blistering and cracking. But this boat is pretty priestine. I'd have to find a good glass person to help with getting it to where I could put thru hull exhaust because the swim platform was molded with the boat hull and doesn't really have a flat vertical area to bring the tips through. Not a big fan of side exit exhaust but that might be a easier route.

I'm not opposed to the vortec heads and they are the better flowing of the production heads. I am just curious why people didn't didn't put just a little bit better flowing head on and why I haven't read of any using a aluminum head. The salt water reasoning makes sense. I live around fresh water.

the 377 is a stroked 350 (3.75" stroke vs 3.48") a 383 is a .030 overbore 377.

head gaskets are usually stainless vs cheep steel. also, the core plugs are brass on a marine unit. If you have a closed cooling system with a heat exchanger, then you can run anything you want for intake or heads without worrying about the corrosion issues. do you have a full system or a half system? with a full system you can also run aluminum exhaust manifolds.

regarding cams and exhaust. if you run thru-hull exhaust and have extended tubes in the manifolds, you can run the more radical cam you have chosen as you have reduced the reversion potential. however there is something to be said about just quietly cruising along at sunset with your best bow bunny without the drone of a thru-hull exhaust. In that case, I would rather hear the blender running than the throb of the exhaust.

from what I know, 5000 RPM is the recommended limit of the VP drives. generally higher than that and your looking at performance drives vs the general outdrive.

the main reason people do not put AFR heads on a boat motor is that the extra BOAT unit per set (one BOAT unit is $1000) doesnt buy you much as compared to box stock Vortec heads.

 

[captmello]

Re: Performance upgrade questions

Nice to see another Baretta owner on the boards. Don't be afraid to post a pic.

The boat in my sig. is a repowered AQ225 305 to a AQ260 350 sbc. I've often considered stroking my motor if I were to pull it for repairs/rebuild but it runs good now.

The cost is a big factor too me as it seems the going rate seems to be 2000-3000 just for parts and machining. Not to mention roller cam upgrades and vortec upgrades. I've often wondered what kind of power increase one could get with a stock nonvortec, non roller cam, 350 to 377 upgrade.

With the bigger boat you are running, I would at least go to a 350, unless the 305 runs good...Most Baretta's I've seen have deep hulls, and like a bigger motor. Good luck with your project, Keep us updated.

BTW, Your outdrive may have said sp...Which would have been correct for that vintage.

 

[mybadford]

Re: Performance upgrade questions

the 377 is a stroked 350 (3.75" stroke vs 3.48") a 383 is a .030 overbore 377.

head gaskets are usually stainless vs cheep steel. also, the core plugs are brass on a marine unit. If you have a closed cooling system with a heat exchanger, then you can run anything you want for intake or heads without worrying about the corrosion issues. do you have a full system or a half system? with a full system you can also run aluminum exhaust manifolds.

regarding cams and exhaust. if you run thru-hull exhaust and have extended tubes in the manifolds, you can run the more radical cam you have chosen as you have reduced the reversion potential. however there is something to be said about just quietly cruising along at sunset with your best bow bunny without the drone of a thru-hull exhaust. In that case, I would rather hear the blender running than the throb of the exhaust.

from what I know, 5000 RPM is the recommended limit of the VP drives. generally higher than that and your looking at performance drives vs the general outdrive.

the main reason people do not put AFR heads on a boat motor is that the extra BOAT unit per set (one BOAT unit is $1000) doesnt buy you much as compared to box stock Vortec heads.

What is the difference between a full system vs a half system in the closed cooling system?

I should be able to put a somewhat longer extended tube just by the way the rear of the hull was designed. I will know for sure as I get to measuring it out.

I sure didn't know that the outdrives had a recommended max rpm. Wonder why that would be?

What do you mean by "BOAT unit per set"? Automotive heads will interchange onto a boat engine, correct? I'm sure you're just using a term I'm not familiar with. I just want to make sure I am on the same page.

 

[mybadford]

Re: Performance upgrade questions

Nice to see another Baretta owner on the boards. Don't be afraid to post a pic.

The boat in my sig. is a repowered AQ225 305 to a AQ260 350 sbc. I've often considered stroking my motor if I were to pull it for repairs/rebuild but it runs good now.

The cost is a big factor too me as it seems the going rate seems to be 2000-3000 just for parts and machining. Not to mention roller cam upgrades and vortec upgrades. I've often wondered what kind of power increase one could get with a stock nonvortec, non roller cam, 350 to 377 upgrade.

With the bigger boat you are running, I would at least go to a 350, unless the 305 runs good...Most Baretta's I've seen have deep hulls, and like a bigger motor. Good luck with your project, Keep us updated.

BTW, Your outdrive may have said sp...Which would have been correct for that vintage.

You're right. The outdrive does say SP. Are they any good?

 

[captmello]

Re: Performance upgrade questions

You're right. The outdrive does say SP. Are they any good?

Yes, they are good, but need maintenence like any outdrive.

 

[Scott Danforth]

Re: Performance upgrade questions

What is the difference between a full system vs a half system in the closed cooling system?

I should be able to put a somewhat longer extended tube just by the way the rear of the hull was designed. I will know for sure as I get to measuring it out.

I sure didn't know that the outdrives had a recommended max rpm. Wonder why that would be?

What do you mean by "BOAT unit per set"? Automotive heads will interchange onto a boat engine, correct? I'm sure you're just using a term I'm not familiar with. I just want to make sure I am on the same page.

half system cools only block and heads. full system also cools the exhaust manifolds. A full system has a heat exchanger that has twice the capacity of a half system.

My guess on the RPM limit on the outdrives is due to the lack of pressurized oil. I suspect Don will respond with the correct answer here.

A boat unit is in reference to $1000. everything I do costs a minimum of one boat unit. since a new set of Vortec's is $500 (half a boat unit) and a set of AFR's is $1500 (1.5 boat units), the boat unit difference is what I was talking about. the extra performance capability of the AFR's wont be realized with an RPM limit of 5000, so why spend the extra $1000

That is why most people simply live with Vortec heads. to gain the marginal benefit is not worth the extra $.

I myself am considering if a 383 block is worth the 1.5 boat units when I have a perfectly good 350. I am leaning toward keeping the extra money for other boat upgrades like a new blender

 

[Maclin]

Re: Performance upgrade questions

Scott,

Your BOAT unit, is this from the

B reak
O ut
A nother
T housand


?

 

[Don S]

Re: Performance upgrade questions

You can do all those engine changes you want, and with a stop watch and accurate record keeping, be able to tell the difference in planing speed, and with a GPS you might average out your top speed runs before and after and see if they changed.
This is a boat, not a car. Things don't work the same.
If you want a "push you back in the seat" feeling difference when taking off from a standing start, you need to change from a single prop lower unit to a DuoProp lower. That, is a performance upgrade.

 

[Scott Danforth]

Re: Performance upgrade questions

Scott,

Your BOAT unit, is this from the

B reak
O ut
A nother
T housand


?

yes

 

[bigbadbowtie]

Re: Performance upgrade questions

Just a side note. The 377 sbc can also be had by using the 350 3.48 stroke crank in 4.125 bore 400 block. Considered an RPM engine by us dragracers.

 

[Tail_Gunner]

Re: Performance upgrade questions

The vortec head design uses a tumble effect, in there time they were far ahead of the field. In essence they improve or are more effective making hp and tq at lower rpm levels. Time has gone by and along came aftermarket products that have been improved over the orignal design and alum is lighter and eaiser to port and polish and quite expensive compared to a gm factroy head....But they are the latest and greatest..

They lend themselves very well to boating after all low rpm high tq what more couold you ask for....Increase the lift and a bit bigger valve hotter cam and its a quick 100 hp gain..and 1500 ofr a 100 hp is cheap in the marine world is cheap. But a 305 voretc head is not the same as a 4.3 or 5.7 head...Not quite the same punch capabilities...ask Gm why they did that i do not know

Best part its all internal work so its marine safe...But cams you have to careful with, overlap can be a problem in that the engine will revert water back into itself at low rpm...600-1200rpm. Bottom line its a great way to tinker get some hp gain nad have fun with your boat....If you call tinkering a good time.

Opps that cam should not cause reversion..very close though.. and if aftermarket heads for a 305 are a true 5.7 vortech design well that would be better but expensive

 

[mybadford]

Re: Performance upgrade questions

Just a side note. The 377 sbc can also be had by using the 350 3.48 stroke crank in 4.125 bore 400 block. Considered an RPM engine by us dragracers.

I was thinkin a 377 was a destroked 400. Or atleast thats the way I usually heard of the combo.

 

[mybadford]

Re: Performance upgrade questions

You can do all those engine changes you want, and with a stop watch and accurate record keeping, be able to tell the difference in planing speed, and with a GPS you might average out your top speed runs before and after and see if they changed.
This is a boat, not a car. Things don't work the same.
If you want a "push you back in the seat" feeling difference when taking off from a standing start, you need to change from a single prop lower unit to a DuoProp lower. That, is a performance upgrade.

I will definitely check planing speeds with a stop watch and top speeds with a gps. The boat is 100% stock. Probably won't do much with it until it's warmer. I will keep everybody posted though.

 

[mybadford]

Re: Performance upgrade questions

half system cools only block and heads. full system also cools the exhaust manifolds. A full system has a heat exchanger that has twice the capacity of a half system.

My guess on the RPM limit on the outdrives is due to the lack of pressurized oil. I suspect Don will respond with the correct answer here.

A boat unit is in reference to $1000. everything I do costs a minimum of one boat unit. since a new set of Vortec's is $500 (half a boat unit) and a set of AFR's is $1500 (1.5 boat units), the boat unit difference is what I was talking about. the extra performance capability of the AFR's wont be realized with an RPM limit of 5000, so why spend the extra $1000

That is why most people simply live with Vortec heads. to gain the marginal benefit is not worth the extra $.

I myself am considering if a 383 block is worth the 1.5 boat units when I have a perfectly good 350. I am leaning toward keeping the extra money for other boat upgrades like a new blender

I haven't seen a heat exchanger on the boat yet. It looks like a hose runs up from the side of the block into the sea water pump and from there it goes into the thermostat housing. There is 3 other hoses coming off of the thermostat housing. There is a hose coming off going into each manifold and another going into the water pump on the engine. I haven't looked at it in great detail yet. The boat is still in the guys garage that I bought the boat from.

 

[Scott Danforth]

Re: Performance upgrade questions

then you have raw water cooling. I would stay away from aluminum heads or intake with raw water unless you ONLY stay in fresh water. There are dual alloy castings for intakes out there that can be used in brachish or salt water.

 

[mybadford]

Re: Performance upgrade questions

then you have raw water cooling. I would stay away from aluminum heads or intake with raw water unless you ONLY stay in fresh water. There are dual alloy castings for intakes out there that can be used in brachish or salt water.

It will be a fresh water only boat.