Mercruiser 898 (GM 305) V8 - Good, Bad, Fast, Slow Engine? Truth Wanted!

[jmw129]

I would like to hear from people who have owned the Mercruiser 898 V8 - GM 305. From what I know this engine is rated at 198hp and believe is a 2-barrel application.

Was this a fast engine?

Slow engine?

Very torquey engine?

Reliable or not?

I don't know anything about this engine as it seem's to me that this 898 is NOT the normal GM 305 application which scares me a bit. Maybe I'm wrong, please correct me if I am. Maybe this engine a "Freak" and people have forgotten since this engine hasn't been made for quite some time now.

Thanks!!

 

[jmw129]

Mercuiser 305 V8 198hp 2-Barrel Converted w/New Intake & 4-Barrel.. HP Gain?

Mercuiser 305 V8 198hp 2-Barrel Converted w/New Intake & 4-Barrel.. HP Gain?

Hey guys,

The engine I'm talking about is a 1983 Merc 898 V8(GM 305) 2-Barrel rated at 198hp. How much Hp should I expect to gain with the 4-barrel & intake combo? 30 more Hp?

Would the engine be the same as the 228hp V8 GM 305?

Also would I have any issues with the engine if I did the combo upgrade?

Would my RPM WOT of 3800 to 4200 change to 4200 to 4600 safely?

I assume the 898 Merc 305 is the same as the Merc 305 228hp motor that has the 4-barrel where the 898 Merc 305 has the 2-barrel application. Intake & Carb is the only difference?

 

[John_S]

Re: Mercuiser 305 V8 198hp 2-Barrel Converted w/New Intake & 4-Barrel.. HP Gain?

Re: Mercuiser 305 V8 198hp 2-Barrel Converted w/New Intake & 4-Barrel.. HP Gain?

Hey guys,

The engine I'm talking about is a 1983 Merc 898 V8(GM 305) 2-Barrel rated at 198hp. How much Hp should I expect to gain with the 4-barrel & intake combo? 30 more Hp?

20-30Hp


Would the engine be the same as the 228hp V8 GM 305?

Should be, but you can confirm that other key parts are the same, like cam, on any parts site, like MercruiserParts.com


Also would I have any issues with the engine if I did the combo upgrade?

It is not a difficult mod. See comment below on engine health.



Would my RPM WOT of 3800 to 4200 change to 4200 to 4600 safely?

Yes, wot rpm should go up.



I assume the 898 Merc 305 is the same as the Merc 305 228hp motor that has the 4-barrel where the 898 Merc 305 has the 2-barrel application. Intake & Carb is the only difference?

See above comment.

Make sure you old engine is in good shape before making the mod. If the rings are worn, valves leaking, etc, just pull it and put in a 350.

Otherwise, a Edelbrock Performer intake and 1409 carb should be a nice match.

 

[John_S]

Re: Mercruiser 898 (GM 305) V8 - Good, Bad, Fast, Slow Engine? Truth Wanted!

I would like to hear from people who have owned the Mercruiser 898 V8 - GM 305. From what I know this engine is rated at 198hp and believe is a 2-barrel application.

Was this a fast engine?

Slow engine?

Very torquey engine?

Reliable or not?

I don't know anything about this engine as it seem's to me that this 898 is NOT the normal GM 305 application which scares me a bit. Maybe I'm wrong, please correct me if I am. Maybe this engine a "Freak" and people have forgotten since this engine hasn't been made for quite some time now.

Thanks!!

The 305 is still in current production. Updated with a number of changes from yours, though. While not known for being a performance engine, they seem to last. If yours in good shape, enjoy what you have and/or tweak to hearts content. If it is worn out and needs replacing, then a 350 would be a better choice.

BTW: Your HP figures are crank rated. For comparing to prop rated, you need to deduct 25-30HP. Current production 305 MPI is 260HP.

 

[mr300z87]

Re: Mercruiser 898 (GM 305) V8 - Good, Bad, Fast, Slow Engine? Truth Wanted!

For what its worth every Camaro and Monty Carlo that had a 305 in has had the engine replaced with a 350. I can not believe the Merc is still using the 305. 305 = Junk. Just my opinion

 

[Silvertip]

Re: Mercruiser 898 (GM 305) V8 - Good, Bad, Fast, Slow Engine? Truth Wanted!

You consider 305's junk just because they don't perform like a 350???????? Could it possibly be that the difference of 45 cubic inches has anything to do with that? The 305 appeared in the GM line during the early emissions period. It had cylinder heads with small valves so breathing at high rpm was limited. The engine was both durable and economical. It was replaced as you said (illegally I might add) because of the abundance of inexpensive 350's and the simplicity of the swap. I will agree -- since performance is a high priority for you, rather than spending money on intakes and carbs, pull the engine, sell it and replace it with a 350.

 

[Scott Danforth]

Re: Mercruiser 898 (GM 305) V8 - Good, Bad, Fast, Slow Engine? Truth Wanted!

the 305 is just a smaller bore version of the 350. the difference is the 3.74" bore vs the 4.0" bore of the 350. both have the same crank and connecting rods.

your engine will only be as good as its maintenance over the last 28 years.

 

[Howard Sterndrive]

Re: Mercruiser 898 (GM 305) V8 - Good, Bad, Fast, Slow Engine? Truth Wanted!

305's are great in boats up to about 20'
a 4barrel conversion adds an honest 20HP to a 305 2V marine engine

 

[John_S]

Re: Mercruiser 898 (GM 305) V8 - Good, Bad, Fast, Slow Engine? Truth Wanted!

"For what its worth every Camaro and Monty Carlo that had a 305 in has had the engine replaced with a 350. I can not believe the Merc is still using the 305. 305 = Junk. Just my opinion "


Have you been in a boat with a 305 vortec? ie a '98 or newer? The stock merc hp is well above those camaro/monty carlos.

and they are such junk that volvo uses them as well.

These days, in the 20' and under boats, many mfgs do not provide a 350 option.

Why a 350 when you could have had a 383? Why a 383 when you could have a 502?

 

[Howard Sterndrive]

Re: Mercruiser 898 (GM 305) V8 - Good, Bad, Fast, Slow Engine? Truth Wanted!

Why a 350 when you could have had a 383? Why a 383 when you could have a 502?

exactly.

and a 305, when at cruise in a smallish boat can be pretty efficient.

With a 350, you need to lean the mixture too much at light load. I know some boaters who have never been to WOT.
a 350 in a 19' bowrider wouldn't be the best for them.

 

[jmw129]

Re: Mercruiser 898 (GM 305) V8 - Good, Bad, Fast, Slow Engine? Truth Wanted!

305's are great in boats up to about 20'
a 4barrel conversion adds an honest 20HP to a 305 2V marine engine

So if adding a 4-barrel & intake then why wouldn't the HP be 228hp like the 305 4-barrel engines that are rated at 228hp? Aren't all 305 GM V8's in the 83-84 years the same?

 

[jmw129]

Re: Mercruiser 898 (GM 305) V8 - Good, Bad, Fast, Slow Engine? Truth Wanted!

305's are great in boats up to about 20'
a 4barrel conversion adds an honest 20HP to a 305 2V marine engine

This engine is in a 19ft boat. Boat weighs 2300 to 2500lbs.

 

[achris]

Re: Mercruiser 898 (GM 305) V8 - Good, Bad, Fast, Slow Engine? Truth Wanted!

So if adding a 4-barrel & intake then why wouldn't the HP be 228hp like the 305 4-barrel engines that are rated at 228hp? Aren't all 305 GM V8's in the 83-84 years the same?

I did exactly this upgrade on a friends boat a few years ago. 23' cuddy. We also added centre riser exhaust manifolds. It increased the boat speed by about 2 knots. He sold that boat to another friend of mine, who pulled that engine and replaced it with my old 4.3. That 'upgrade' increased boat speed by 6 knots!

Chris........

 

[Howard Sterndrive]

Re: Mercruiser 898 (GM 305) V8 - Good, Bad, Fast, Slow Engine? Truth Wanted!

So if adding a 4-barrel & intake then why wouldn't the HP be 228hp like the 305 4-barrel engines that are rated at 228hp? Aren't all 305 GM V8's in the 83-84 years the same?

I don't know why there are so many different 305 horsepower ratings.
OMC had a 305 in 1979 that was a 2 barrel rated at 175HP (???). I can't imagine what is holding it back. Must be camshaft grinds, if anything... could also just be a conservative rating for marketing purposes.

 

[jmw129]

Re: Mercruiser 898 (GM 305) V8 - Good, Bad, Fast, Slow Engine? Truth Wanted!

I don't know why there are so many different 305 horsepower ratings.
OMC had a 305 in 1979 that was a 2 barrel rated at 175HP (???). I can't imagine what is holding it back. Must be camshaft grinds, if anything... could also just be a conservative rating for marketing purposes.

I don't disagree with you one bit. That's why it's confusing because you hear people say oh that V8 305 and that V8 305 are the same except for ONLY this part or these set of parts.

You would think the intake & carb are the only difference but maybe the cam is different or crank etc?? on these stock engines.

 

[John_S]

Re: Mercruiser 898 (GM 305) V8 - Good, Bad, Fast, Slow Engine? Truth Wanted!

You would think the intake & carb are the only difference but maybe the cam is different or crank etc?? on these stock engines.

http://www.mercruiserparts.com/selectModels3.asp?type_id=8

http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=99985



Crank different-no
Cam differnet-no
Pistons different-no
Ignition Amplifier different-no
Head Gaskets different-no
Cylinder heads have a different part number:
http://www.mercruiserparts.com/Show...INDER+HEAD+AND+ROCKER+COVER+(898-200-228-230)



It looks like there are different valve between the heads, too.

 

[greg82255]

Re: Mercruiser 898 (GM 305) V8 - Good, Bad, Fast, Slow Engine? Truth Wanted!

2 years ago i had the exact same package in almost the exact same boat (see my signature). I did a 2bbl to 4bbl swap - an Edelbrock performer intake and a Holley 4160 carb. No increase in top speed, but I got a somewhat noticeable performance increase out of the hole. The 20-30 hp you gain by adding that combo equals about 2-3mph, and you can easily vary that much due to water conditions. I spent about 500 on all the parts I needed to make the swap.

If I had to do it all over again, I would have just dropped in a used 350 or bought a long block from rapido or some other shop.

 

[jmw129]

Re: Mercruiser 898 (GM 305) V8 - Good, Bad, Fast, Slow Engine? Truth Wanted!

2 years ago i had the exact same package in almost the exact same boat (see my signature). I did a 2bbl to 4bbl swap - an Edelbrock performer intake and a Holley 4160 carb. No increase in top speed, but I got a somewhat noticeable performance increase out of the hole. The 20-30 hp you gain by adding that combo equals about 2-3mph, and you can easily vary that much due to water conditions. I spent about 500 on all the parts I needed to make the swap.

If I had to do it all over again, I would have just dropped in a used 350 or bought a long block from rapido or some other shop.

So you think the 260hp vs. 230hp in the 305 would make a big difference? A reman 350 engine is $1,300+ unless you're talking block with pistons, crank, and cam only?

 

[achris]

Re: Mercruiser 898 (GM 305) V8 - Good, Bad, Fast, Slow Engine? Truth Wanted!

So you think the 260hp vs. 230hp in the 305 would make a big difference? A reman 350 engine is $1,300+ unless you're talking block with pistons, crank, and cam only?

I think in this case (305/230hp vs 350/260hp) the difference is more about the torque than the horsepower.

 

[John_S]

Re: Mercruiser 898 (GM 305) V8 - Good, Bad, Fast, Slow Engine? Truth Wanted!

If your priority is speed (or power) and you are going to swap in a 350, put in one with vortec heads, not like the 260 with standard heads. You are leaving an easy 30hp on the table.

In general, more displacement means more torque, and will improve your on plane times, and pulling power. Peak HP will get you more wot speed. With a 350, you gain in both. Modifing the 305, mainly only the latter.

While Merc and Volvo don't post HP/torque curves, GM does: http://www.gmpowertrain.com/MarineEnginesControllers/ProductPortfolio.aspx

These would be fairly close to current merc/volvo mpi offerings.