Big Block Dennis Moore...Book or information..

Stan's Customs

Petty Officer 2nd Class
Joined
Oct 30, 2004
Messages
161
Wouldn't you know ...Finally got a small block version Of D. Moore's book and I wind up with a freeze damaged Big Block to build.<br /><br />I've been saving a low mileage 454 core with a cracked piston, in case one of my wrecker engines needed replacing. But...I've decided to use it in this boat because I'm sure the crank is standard etc.<br /><br />I'm curious what Mr. Moore recommends for a big block configuration ...especially in the head department. I'm thinking big oval port...wish I had some numbers to match up to or get close...His compression recommendations would nice too...<br /><br />Anyone got one of his Big Block Books for sale? I'd pay well..and for 2nd day air cost.<br /><br />If not I'd be curious as to anyone's past experience with successful combinations. I'd really like to have an engine built and ready to set in before I tear down the boat and see what it came with. That way my shop won't be tied up so long with the repower. The boat has a 1991 Mercruiser 454/Bravo. Cam recommendations would be of interest too... <br /><br />I think this was a 300 hp engine ...more would be better of course...<br /><br /><br />Thanks...Stan
 

MGallik

Seaman
Joined
Apr 4, 2003
Messages
71
Re: Big Block Dennis Moore...Book or information..

Stan, you need the book. There are just too many choices to make for the big blocks to do it here.
 

Stan's Customs

Petty Officer 2nd Class
Joined
Oct 30, 2004
Messages
161
Re: Big Block Dennis Moore...Book or information..

Hello 1900sx...<br /><br />I agree...but the forum is abount the only other reliable information source. The book is out of publication and I have spent several hours on the net searching. Maybe one will come up on E-bay sooner or later. I found the small block book after about a month of diligent daily effort. I'm anxious to build this engine..while business is a little lax. Things will pick up soon and I'll have to just build what "I" think is best if I don't get some input from those who have some successful combinations they might like to share.<br /><br />I guess it's not that critical with these poor breathing exaust. Can't really run a good cam ...high rpm hp doesn't work in boats. Guess I'll just build a truck engine with an aluminum intake and maybe a Comp 268 cam ...keep the compression around 9.5...Gotta buy manifolds...so I suppose Dennis Moore's probably are about as cheap as any and flow a little better than stock. Just wish I had a little first hand experience with a big block in a boat. I've had many of them in other work and performance street applications....so I'm sure I'll come up with something.
 

MGallik

Seaman
Joined
Apr 4, 2003
Messages
71
Re: Big Block Dennis Moore...Book or information..

OK Stan, tell me what drive and final ratio you have and I'll part out a suggested engine for you from the book.<br /><br />Give me an idea what you want it to be and do.<br /><br />What engine block like Mark IV or Gen V, year, heads, intake, carb, etc is yours. Want a roller cam? Any ideas on ignition type?
 

Stan's Customs

Petty Officer 2nd Class
Joined
Oct 30, 2004
Messages
161
Re: Big Block Dennis Moore...Book or information..

Oops....<br />I see that I haven't mentioned in "this" thread that the boat is a 1986 Sea Ray 19ft. Bow Rider.... only that the drive is a 1991 Bravo 1 and 454. Sorry 'bout that...
 

MGallik

Seaman
Joined
Apr 4, 2003
Messages
71
Re: Big Block Dennis Moore...Book or information..

A 19'er with a 400 horse BB? Lookin' to give the Baja's fits are ya......<br /><br />You do know that with the little gas tank in that boat you won't be passing many marinas (gas stations).
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Big Block Dennis Moore...Book or information..

You will probably find a stock 454 with 300hp is plenty for any 19ft boat. Any go fast stuff is just going to cost more money and use more fuel with an engine that is already thirsty. Besides that, the Bravo 1 lower is about at it's limit at a 300 horse engine. For higher horses, Mercruiser went to the Bravo 2 and 3 drives.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Big Block Dennis Moore...Book or information..

Oops....Duplicate post
 

Stan's Customs

Petty Officer 2nd Class
Joined
Oct 30, 2004
Messages
161
Re: Big Block Dennis Moore...Book or information..

Thanks 1900sx..<br />The rebuilder engine I have in mind is a stock 454 truck engine from a 1985 Chevrolet 1 ton truck.( had a cracked piston..50K motor)<br /><br />The boat engine that I'm replacing is a 1991 stock Mercruiser 300 hp 454, Bravo 1...it was a very strong engine and complete with stock Mercruiser carb and ignition as manufactured in 1991.(till they let it freeze) Even though the boat is a 1986 ...the engine and drive is a 1991 and clean... looks like it came in the boat. The drive ratio is 1.50:1, courtesy of information from Don S.<br /><br />I imagine I would use the stock Mercriuiser Q-jet and the stock ignition and stock thru hub exhaust....But nothing is set in stone. The idea is to build as strong running 454 as I can, that will still idle for water sports... skiing and the like....I'm after every bit of horsepower I can get without getting exotic...aluminum heads for instance, don't imagine they would help that much anyway? I have access to most any Chevrolet stock stuff..so again nothing is set in stone.<br /><br />A roller cam is fine...if the gain is worth the expense, no problem. But I'm a working man and money needs to be well spent, if you follow my meaning. I won't scrimp to do the job right but little input on a roller for a boat would be good.<br /><br />Heads and cam are the questionable area for me on a boat like this...and ignition and...
 

MGallik

Seaman
Joined
Apr 4, 2003
Messages
71
Re: Big Block Dennis Moore...Book or information..

Roller cam, Here <br />Flat tappet cam, Wild or Mild<br /><br />I ran these as 1991 but the same cams are used in the 85.<br /><br />Sorry, but I like Crane Cams. Comp Cams stuff makes noise not power. Had a lot of returns when I used their roller rockers in the 80's.<br /><br />Heads<br /><br />230cc open chamber, large oval port, Casting #781 or #049<br /><br />Intake<br /><br />Stock low rise with the dividers between the primary and secondaries removed and the sharp edge where the airflow turns under radiused and smoothed. Just a bit better than stock.<br /><br />Stock high rise cast iron<br /><br />Performer RPM 2-O (oval port square bore carb) part #3261<br /><br />Performer RPM 2-O Q-Jet (oval port spreadbore) part #3264<br /><br />Holley part #300-42 (A copy of the excellent Chevy cast iron high rise, square bore only)
 

Stan's Customs

Petty Officer 2nd Class
Joined
Oct 30, 2004
Messages
161
Re: Big Block Dennis Moore...Book or information..

Hell Don...<br /><br />Well, that puts a damper on bigger horsepower...I didn't know that the Bravo 1 was about at it's limit at 300 hp...I was under the impression that the limit for the Alpha 1 was about 300 hp and the Bravo 1 was significantly more...thought I saw that from this forum somewhere....scuttlebut maybe.<br /><br />Guess that needs to be taken into consideration 1900sx....<br /><br />This boat has Bennet trimtabs if it matters..
 

MGallik

Seaman
Joined
Apr 4, 2003
Messages
71
Re: Big Block Dennis Moore...Book or information..

I think he's wrong on the B1 hp rating. Thats the Alphas limit. Most of the Bajas use the B1. Check at Merc. I did........<br /><br />
Specifications<br />SmartCraft: Yes<br />HP: 375<br />kW: 280<br />Displacement Liter/CID: 8.1/496<br />Cylinder/Configuration: V-8<br />Bore & Stroke (in): 4.25 x 4.38<br />Bore & Stroke (mm): 108 x 111<br />Compression Ratio: 9.1:1<br />Fuel System: MPI<br />Full Throttle RPM Range: 4400-4800<br />Ignition System: PCM 555 Distributorless<br />Alternator Amp: 65<br />Alternator Watt: 917<br />Drive/Gear Ratios (primary/optional/high altitude): Bravo One: 1.5/1.36/1.65:1<br />Drive/Gear Ratios (primary/optional/high altitude): Bravo Two: 1.81/2.00/2.2:1<br />Drive/Gear Ratios (primary/optional/high altitude): Bravo Three: 1.81/2.00/2.2:1<br />Total Weight (lbs./kg): Bravo One: 1199/544<br />Total Weight (lbs./kg): Bravo Two: 1216/553<br />Total Weight (lbs./kg): Bravo Three: 1225/55
The B2 is engineered for cruisers and not used on performance boats. The B3 is for less prop slip out of the hole and during cruise in heavier boats and actually hurts performance above 60 mph.<br /><br />By the way, this things going to be an animal. I'd recommend at least a 21 pitch stainless prop, with all that torque in such a little boat you should break 70 mph easily with a 23 pitch stainless.<br /><br />DON'T try turning too fast over 60 and pay attention to wind lift on rough water or windy days. My 19 foot Chaparral gets a little light in front at 60. I haven't built the engine for my 21 footer yet......
 

Stan's Customs

Petty Officer 2nd Class
Joined
Oct 30, 2004
Messages
161
Re: Big Block Dennis Moore...Book or information..

Hello 1900sx...<br /><br />I like Crane Cams too...but I've had good luck with both actually.<br /><br /><br />Thanks for the links, good information ...I'm pleased about the head suggestion, I was hoping something along that line would suffice.<br /><br />I'll run a Q-jet for sure.... probably the Performer would be my choice of intakes (I may even have a used one). Cam.. Can't make up my mind about a cam at all ...no boat experience.<br /><br />Just out of curiosity which intake and cam would you use specifically...
 

MGallik

Seaman
Joined
Apr 4, 2003
Messages
71
Re: Big Block Dennis Moore...Book or information..

My intake would be the cast iron high rise or the Performer RPM 2-O Q-Jet.<br /><br />I think the mild flat tappet cam above would be a great choice but I really like rollers and would use the one I listed.<br /><br />The wild isn't all that "wild", but it is a bit more than you need.<br /><br />Don't forget those heads need to be open chamber.
 

Stan's Customs

Petty Officer 2nd Class
Joined
Oct 30, 2004
Messages
161
Re: Big Block Dennis Moore...Book or information..

Thanks again 1900sx..<br /><br />The boat has a nearly new Mercruiser Mirage 21P prop....I also have a Brand new Torque Shift prop I bought several years ago for an old 19ft Baja and never got to use...(long story , paint shop went out of business lost all hardware on boat..) I don't know if the Bravos will accept the same prop as the 260 Mercruiser on that old 1979 Baja...Do you know? I haven't dug it out to see.<br /><br />Yea...I kinda figured it would get light if I hit a wind gust head on...had an incident once a long time ago...spooky when that happens....I've been more cautious ever since.<br /><br />You know I have a 1986 Four Winns 200 that has an OMC Cobra and a 5.7 with blowby. I'm not to proud of the boat, at least the drive and engine. Bought it sight unseen..... even though I bought it in North Texas it turned out to be a saltwater boat...corosion all over engine and drive and lotsa rust scale in block, risers, etc.<br /><br />Anyway...I like the hull, even though it's a 20 ft boat its a lot bigger than the 19' Sea Ray...Taller, wider...biggest 20ft I've seen..Wonder If I'd be ahead transplanting this Bravo stuff into it. I'm sure it would be much stabler...don't know what I could expect performance wise.....I've always had 19ft. boats it seems, or smaller.
 

MGallik

Seaman
Joined
Apr 4, 2003
Messages
71
Re: Big Block Dennis Moore...Book or information..

Oops, pistons. <br /><br />With the 118cc open combustion chamber head and the standard domed marine pistons from Chevrolet (a closed chamber piston) the 454 will have an 8.75:1 compression ratio. Both Chevy and the aftermarket can supply pistons with domes to make compression ratios as high or low as desired. <br /><br />I wouldn't go much higher than 9.5:1, regular (gas) is much easier to get at a marina and big blocks much over 9.5:1 ping under heavy load on regular. By the way, the recommended compression of the roller cam is lower (8.75:1) than the "mild" (9.5:1) flat tappet.<br /><br />Flat top pistons only make 8.0:1 compression with those heads, "thumbs down", says Dennis....<br /><br />On boat size, a longer thinner boat won't catch air and fly like a shorter, wider one will. That engine drive combo would be perfect in a 21 or 22 footer with a 40+ gallon fuel tank. If the boat came with that engine, it will be fine. The beast you're building won't be all that much more than the stocker. Well, at least it's not an 11.0:1 alcohol burner. There's a few of those on the river I boat in and those goofs are all still alive. :D <br /><br />Time for bed, catch ya tomorrow Stan.
 

Stan's Customs

Petty Officer 2nd Class
Joined
Oct 30, 2004
Messages
161
Re: Big Block Dennis Moore...Book or information..

Lower compression is one of the advantages of the roller cam I keep overlooking for a boat. Marina fuel is notorously poor grade around here.<br /><br />This is where D. Moores book come in handy. His book gives part specific numbers for the Chevrolet heads pistons etc. That's one of the best things about his small block book for sure. Lots of infornmation about what years parts were used and their part numbers.. huge time saver when you working up a parts list..I've gotta find a big block book sooner or later.<br /><br />My Machinist has an old bus full of Chevrolet heads and hard to find cores...gota get some numbers and see see what he has. Need to tear down my core engine and get some numbers off it too...not sure what the chambers are on the old truck heads...<br /><br />Yea... compared too this engine is a mild motor...but 40 or 50 extra hp should be easy to get. I just don't want to waste money that won't yield much gain on this restricted motor...don't want to leave any easy hp on the work bench either. It would be real easy for me to over build ...This is just a stock motor for street you might say...
 

Stan's Customs

Petty Officer 2nd Class
Joined
Oct 30, 2004
Messages
161
Re: Big Block Dennis Moore...Book or information..

Hmmm...<br /><br /> I may have a problem with my doner engine...it's a 2 piece rear main. A 1991 Mercruiser is a 1 piece rear main I bet...unless they were a couple of years behind... as my machinist suggest they are some times. Does anyone know whether the 1991 Mercruiser is a 1 piece or a 2 piece.....
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,241
Re: Big Block Dennis Moore...Book or information..

Ayuh.... You're Right there Stan.......<br /><br />Even though you can't use the flywheel from the Newer motor, A Flywheel from your wrecker motor Should accept the Bravo Coupler..........<br />I believe the Bravo Coupler uses an 11" clutch bolt pattern.......
 

Stan's Customs

Petty Officer 2nd Class
Joined
Oct 30, 2004
Messages
161
Re: Big Block Dennis Moore...Book or information..

Hello Bondo..<br /><br />You mean a heavy clutch type flywheel with an 11" pressure plate pattern will work ( my wreckers are automatics)....I thought the coupler bolted to the hub center or crank bolts. That would be great...save me a bunch if I can still use this motor.<br /><br />I'd really like to use forged pistons and get some better heads, having to buy a block would make a difference on what I do.
 
Top