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Teddy
08-03-2010, 10:43 PM
First, I apologize for any "newbie" mistakes in this post. I am in need of the advice from the Donzi fanatics with HM/Volvo experience.

I currently own a 1969 HiLiner 21 with a 302/Volvo 270. The engine is a 1974 190hp with HM housing, logs etc.

I recently picked up a HM 302/Volvo 250 combo from the water pump to the elephant ear prop. The block appears to be a 1968 with the Holman Moody tags; 235hp, 10.5- 1 CR. To my surprise the engine has an Edelbrock?600, mallory Ignition, ford racing roller rockers, hardened pushrods and double valve springs.

Questions for the HM performance gurus. Is this engine worthy of freshening/rebuild other than being period correct ?

How much of a difference will these performance items add to this engine? Various posts and rumors stated that these 302's went pretty well.

mphatc
08-03-2010, 11:40 PM
Teddy,
Welcome!
From everything that I've learned over the years the H&M marine engines were not as modified or developed as what you're describing.
I own a 1969 Donzi that was originally a 302 H&M package, and the engine was nothing elaborate. I believe H&M primarily marinized the Ford production engines.
I'd venture that someone in the past modified this engine with the accessories you listed.
Is there an actual H&M serial number on the engine? I presume this tag is attached to the bellhousing? From this number there are folks here that can decipher exactly what the original package was.

Mario L.
1969 Corsican
1968 Magnum 27

mattyboy
08-04-2010, 07:28 AM
as Mario said Holman Moody marinized ford motors and basically went to the expense of having the H/M cast printed etched stamped or stickered on everything . so they bought all the parts from the MFGR's with their markings on them and assembled the motors in some cases they even rigged the boats
. My 67 HM 16 actually had a HM part number on the torque tab of the drive.

the 235 hp 302 was an HM offering, HP ratings were inconsistant at best back then. One item that was unique to HM was the raw water cooling setup a crank driven crossover system using a jabsco pump.

the serial number plate will tell you the hp, compression,timing,what size carb, and a few more things.


with that said I bet someone freshened the motor and put some new parts on it, the intake would more than likely not have edlebrock on it but a HM part number it.

post the all the numbers you can I can decipher them for you

Teddy
08-04-2010, 08:32 PM
Mario and Mattyboy,

Thanks for your responses.

Here is the full tag info.

Serial # - D9HM-3286 1-RW-I/O
CPM - 235 4v C6HM-MB1
CR - 10.5:1 TM 12 degrees

FYI - The first three years of Hiliners (68-70) came with HM/Volvo packages. The valvetrain and carb were certainly added at some later point (blue anodized roller rockers). Heads are marked 302 under the valve covers. I also have the factory thru-hull exhausts.

No expectations to run this boat in the Donzi speed territory, just trying to decide if this motor is a worthy reliable replacement for more fun and speed than I can currently achieve.

The boat currently will run to 45 at 4400 rpm, friend had the same boat with a 250 HO on a gill that ran 62-63 on GPS. Mostly wondering if this valvetrain will run to mid '5 rpms and still make more reliable ponies than the 235 on the tag.

Love my HiLiner, Lust for another Donzi.

Ted

MOP
08-04-2010, 09:16 PM
IMO the Ford blocks were great for marinizing, if the engine has been run in fresh water I would not hesitate freshen it up. When done I would prop it close to but under 5,000, I think you will be please with the extra ponies. The biggest draw back was the small port heads, a set of decent flowing heads does wonders for the SB Fords.

mphatc
08-08-2010, 11:01 AM
Teddy,,

If you chose to refresh the engine, I have a set of ported GT40P heads, resurfaced to bump compression, double valve springs, all set ready to rock!

Mario L.

8950LX
09-02-2010, 12:14 PM
First, I apologize for any "newbie" mistakes in this post. I am in need of the advice from the Donzi fanatics with HM/Volvo experience.

I currently own a 1969 HiLiner 21 with a 302/Volvo 270. The engine is a 1974 190hp with HM housing, logs etc.

I recently picked up a HM 302/Volvo 250 combo from the water pump to the elephant ear prop. The block appears to be a 1968 with the Holman Moody tags; 235hp, 10.5- 1 CR. To my surprise the engine has an Edelbrock?600, mallory Ignition, ford racing roller rockers, hardened pushrods and double valve springs.

Questions for the HM performance gurus. Is this engine worthy of freshening/rebuild other than being period correct ?

How much of a difference will these performance items add to this engine? Various posts and rumors stated that these 302's went pretty well.
I don't know how serious you are about making your motor period correct but I actually have a Holman Moody 302 aluminum 4bbl high rise intake. Part # C8HM-9424-2. I'm not sure if these were ever used in marine apps. or not. You can reach me at turbo92lx@att.net if interested. thanks, Bill

Morgan's Cloud
09-02-2010, 02:08 PM
Which model is yours Ted ? The centre console or the 'mini moppie' . .

Many moons ago , we had about 4 of them imported .. I can recall two o/b's (C/C's) and a mini moppie that had the electric shift OMC 302 in it.

Someone , not unknown to me ... found an I/O C/C model and semi restored it and dropped a 385/454 Volvo DP in it ... I don't think he ever opened it up before an installation problem crippled the boat and he lost interest (and ran out of cash ) .

Teddy
09-02-2010, 10:48 PM
The model is called a sportsman (mini-moppie), I actually looked at two I/O cc before buying this boat, but both needed a lot of work. We had 4 good size adults and four kids on it last weekend and even with this low hp engine the boat rode well and got into the mid 40's. I've only had the boat out about 8 times and I'm finally getting a feel for how it handles in different conditions.

I'll soon be planning the off season projects, hopefully installing the HM 235hp.

How did you like the boat?

seano
09-03-2010, 02:12 PM
wasnt the hiliner a spash of the 20 Bertram? there is a red one near me that looks strangely like a bertram.

HOWARD O
09-03-2010, 08:30 PM
My brother's 1969 16' has the HM 302 235 hp. It does have the double springs and we were surprised to see that, but honestly don't know if that was original or not. Kind of figuring it is. I think it's a Carter AFB on it too.

That boat is a running machine and I think 235 hp is underrated.

HOWARD O
09-03-2010, 08:32 PM
wasnt the hiliner a spash of the 20 Bertram? there is a red one near me that looks strangely like a bertram.
There's one in the yard at a marina down the street from me! I took a second look driving past it just yesterday. I thought it was a Moppie, but it's a Hiliner. Great looking boat....if you like that utilitarian Bertram look as I do.
Here's one for sale, complete with HM 302. Even has the HM badge on the outdrive too. Great boat. http://www.yachtworld.com/core/listing/boatMergedDetails.jsp?boat_id=2251209&checked_boats=2251209&ybw=&units=Feet&currency=USD&access=Public&listing_id=74793&url=