305 SBC upgrades
 

Hi all,

I'm new to this forum. Little bit about my project. I have an 89 baretta phaser 230 with a Volvo penta aq231a 305 ci motor. Stock she's rated at 230 hp with a single prop vp 290 drive and 230 hrs. Since its a nice project boat I'm looking to liven her up a little.
I'm thinking on installing a pair of trick flow super 23 175 alum heads and a new cam. Along with marine power alum mp2k manifolds/risers. I plan on keeping the through transom plate exhaust to keep it abut quieter but have removed the exhaust bellow and installed a flapper. It's sounds great IMHO not too loud but louder than stock. Anyways I'm wondering about some experienced input about a cam that would get ~300 hp with the above setup and not have water reversion issues if possible...

Thanks

You will not see much changing the cam. The exhaust will be minimal gain if any. If my memeory is correct the 305 had closed chamber heads, years ago lots of racers put them on there 350s to build compression.
Keep that in mind if buying heads.

My first V8 in a boat was a 305. I tried to make changes just like you with nill results but it was louder so I thought that was cool. Remember that was over30 years ago! Then I went on to building a 350 for the same boat. It just never ends trying to get more speed. I just pulled 3 year old brand new 502 engines out to refresh them.:grinser010:

Sell the 305 complete,,,,,and buy a used 350 300HP Mag complete..

Most economical and reliable way to do it.

Do yourself a favor and try to find a good 350 or better yet a 383 to drop in the boat in place of the 305. Wrap the 305 up and keep it as a spare in case you blow up the other engine or sell the boat. The cost of the Trick Flow heads and cam would probably be at least halfway to the cost of the complete engine, and without much better exhaust / intake you will probably not realize much bang for your buck with the cam / heads upgrade to the 305. Besides, you don't really know the condition of the bottom end of that 305 judging by your description. I also tried to upgrade a 305 in my Camaro way back in the 90's, and the small bore severely restricts airflow around the intake valves. There's just not that much you can do with them. Remember, cubic inches and torque is the key to getting a boat moving in the water. With the bigger engine you can realize better gains without having to deal with the possible reversion issues of a more aggressive cam.

350 or 383 all the way. you will put the cost of making your 220HP 240HP. While in the process spending the cost of a 350 long block.

I have a healthy complete drop in small block w 40 hrs on it $2000 alum intake
Crane cam roller rockers dart heads forged pistons. Stainless marine manifolds Ect

Sorry I have to add to this; taking out a 6.2 MPI 377 320 hp, 300hrs. $5000.00 Includes; maniflods, EFI , fuel pump canister, flywheel and balancer. I must keep the bellhousing, seawater pump, alternator, power steering pump and the accessory bracket with pulleys. We are building a new package. This engine has a 4340 3.750 crank already, we were going to build off the short block, but are selling all the not needed parts and figured selling as a whole package.

I thought about a nice 350 n 383. thing is you can't get props for older vp 290 drives higher than 23 pitch.. Im using a 21p n its right in the middle of the recommended wot range. That n I wanted to use what I already had. But I'll look into a 3 fiddy. I'd like to keep the weight down with aluminum parts. That be a lot probably close to a 100 lbs off the stern

What do you guys think of one of these? http://www.ebay.com/itm/Mercruiser-V...dc88b2&vxp=mtr

Is that a single or dual prop design? If single, any competent prop shop should be capable of working over the blades to add some cup or give you a couple of extra inches of pitch.

I would want to know what parts go into that "reman" 350. You would be horrified to see what kind of manufacturing practices go on in some of those volume reman shops. Read the fine print on the warranty carefully.