188 vs 5.0L volvo

[existingmember]

Hi guys. I have to make decision repowering 1977 bellboy. The boat weighs between 5000 and 6000pounds. I have limited size for fuel tank @ 40 U.S. gallons. I had a cruise limit of @ 60 miles or 3hrs. with tired 302. Anybody have an idea of probable range with fresh 302 vs fresh 270 H.P. 5.0L. volvo. There is a significant price difference but if it improves my range considerably then I'll have to seriously consider it.Fuel tank is in floor and is what it is.Thanks in advance.

 

[bluewater19]

Re: 188 vs 5.0L volvo

You will have big problems with that.<br />The 302 you are talking about is a ford based motor.<br />The new volvo 270hp 5.0 is a chevy based motor and won't bolt up to the same bellhousing. <br />Sorry.

 

[JasonB]

Re: 188 vs 5.0L volvo

My 302/188/888 that I rebuild 3 years ago (beefed up a bit, flat top pistons, better cam, bored 30 over, hi-volume oil pump, etc with the stock 2bbl carb-for now) pushes my 19'deep V hull Glastron Bowrider, about 3400lbs loaded with just me, the wife, and 36 gals fuel, to about 49mph WOT at about 4k rpms and I an cruise at 30-34mph and get 3-5 MPG on depending how I run it. If your drive is in good shape, I would rebuild that 302 and keep trucking. It's a great motor/drive combo. The FI volvo would get you better economy, but that's going to be a chunk of change to put down.

 

[existingmember]

Re: 188 vs 5.0L volvo

Thanks for the info,JasonB. That's the sort of numbers I think I could get with 5.0L allowing for the extra weight for a 22'. I would like to cruise at 30 or more and am afraid the 302 can't do it on this hull. Hopefully the better fuel economy would extend my range somewhat. It's a big coast.

 

[JasonB]

Re: 188 vs 5.0L volvo

You could pretty easily drop in a 351 as well without needing a new bellhousing, exhaust, etc. The 351 would get you the hp you want and with its extra umph, may get you close to the fuel economy. The big problem, to me, in converting to a GM block is that you will have to move the motor mountig points. On my boat, that would be a nightmare where the mount studs are embedded in the stringers. The actual connection to the outdrive would be interesting, but since mercruiser primarily used GM engines, the parts are readily available. My rough guess for drive parts would be bellhousing, motor mounts, and maybe a Y pipe? If you could find a donor boat, that would make it easier.<br /><br />Have you considered a new dfi or 4stroke outboard on a bracket? That might get you where you want, but would make for a fun time of filling the transom.<br /><br />I just saw a price on that 5.0 somewhere on the net (before shipping) of almost $7,000 for the engine alone, or just over $10,000 with an SX drive. That doesn't include the labor to install either. A couple thou in a 351 might not be a bad option, you just might need to re-prop. <br /><br />During the 90's, OMC produced a fuel injectes 302/5.0 Ford that was rated at 245 hp I believe. If you had your 302 built up a bit (or 351) and added a Holley pro-jection kit (I think they run under $1000?), you may get what you want for somewhere in the $2-4k range depending on if you do the work or not, without the headaches of trying to put a GM block engine in there and dealing with the controlls needed for the newer engine.<br /><br />Another thought, is there anywhere else on the boat where you could put an additional tank? My boat has two tanks connected through a valve. Each 18gal tank is in the base of the lounge seats.<br /><br />The 188hp 302 Merc build is an interesting beast. I think the pistons were chosen more to keep the compression Ratio down and combat poor fuel more than anything. The few mods I did to mine when I went through it really woke it up. I would love the fuel injection, but budget has me slowly collecting the items i need to go to a 4bbl carb.

 

[f_inscreenname]

Re: 188 vs 5.0L volvo

Jason seems to know what he is talking about.

 

[JasonB]

Re: 188 vs 5.0L volvo

Prawner, I double checked at NADA to see if the listing for your boat might shed some light to see if your boat has gained weight over the years. If your estimage of 5000-6000lbs is accurate, you may want to check under the floor for some wet foam. Just for reference, the 23' cruiser model with the 120hp 4cyl sterndrive is listed at 4200lbs. Odd that a boat that heavy would be listed with that size engine. What type of hull is yours? If it is a deep hull that plows a bit even when on plane, and has some extra weight, that may explain a bit of your performance and fuel economy woes. I know my last trip out, my trim went out with the engine trimmed about neutral so I couldn't get proper trim to get the nose out of the water on plane. between that, and 3 other people, I burned over twice as much fuel as normal. to make a 10 mile or so run. <br /><br />Might be worth checking the model of your boat there to get an idea of the weight new and get it weighed to see if you have some extra weight there that isn't gear. I plan on doing this next year.<br /><br />Just for reference, the weight of a 1976 888 drive and engine was listed by Glastron at 975lbs.

 

[rodbolt]

Re: 188 vs 5.0L volvo

hello<br /> I got a feeling that if you go from a 188 hp to a 270 hp you will find a decrease in fuel economy. the extra power comes mostly from extra air and fuel.<br /> if you decide to go with an EFI motor be aware that a few models require a fuel return to the tank. most are a pain to install retroactivly.<br /> you may have a look at a 200 hp 4.3 and a XDP volvo package. good power to weight and decent performance.

 

[existingmember]

Re: 188 vs 5.0L volvo

Awesome info guys. Jason what's nada and where do I find it? By the way the 5000-6000 quote was a total guess. If the numbers you got with the 4 cyl are correct then I would still guess aroun 5000. Have started to consider 4.3L as well. It should use less fuel and has a bit more power than 302. The $1000.00 lighter price tag might have some input too! Good to know about fuel return line Rodbolt it must be for pressure relief with electric fuel pump?

 

[JasonB]

Re: 188 vs 5.0L volvo

www.nadaguides.com<br /><br />Here's the Holley FI System: http://www.holley.com/HiOctn/ProdLine/Products/Marine/FMS/FMSFI/700-21.html <br /><br /><br />With the 4.3, you will get lighter weight, but will still have to account for changing to GM mounting. Your 302 can easily be built to 225+ without any sacrifice in reliability, esp. with FI and you wouldn't have to touch the drive system, just the engine. A couple hours to pull it, whatever to rebuild/upgrade it, then a couple to drop it back in.<br /><br />Just cal me JasonB - Crusader for the almost extinct 188/888 Mercruiser!

 

[rodbolt]

Re: 188 vs 5.0L volvo

hello<br /> the return line is for excess fuel from the high pressure rail. most systems use a non return line. a few use a line from the pressure regulator back to the tank.

 

[DJ]

Re: 188 vs 5.0L volvo

Prawner,<br /><br />The simplest way is to go from 302 (5.0) to 351 (5.8). Look for 5.8's after 1993. They are easily converted to marine. Soft plugs, water pump, etc. Getting over 300 ponies out of a 351 is a "soft mod" if you are so inclined.<br /><br />The 1993's and up were, "PI" engines (power improved). They were much different. New crank, heads, cams, etc. Real torque generators. Great life too.

 

[rodbolt]

Re: 188 vs 5.0L volvo

hello<br /> be aware on the 302 and 351 engines there were many flywheel/crank changes over the years. the 351 windsor and the 302 were very similar. the 351 windsor has been out of prouduction a long time. the 351 cleveland and the 302 had blue paint in common and nothing else. the 351/400 was a modified cleveland engine and wont interchage many parts between the 302. years ago when hot rodding we saw it all but my memory is getting fuzzy . but if you use the correct flywheel and bell housing all will be happy.