My son and I have been discussing doing some renovation work on a Donzi we have had in the family for 40 years. It is a '69 18 with H&M Ford/Volvo power. I would brag (without facts) that this boat has to be in the top 5% of all unrestored Donzis of its era. It is almost like a new boat with orig gelcoat and all original power (except for a couple of head changes over the years). We started thinking about upgrading the power as the boat still runs around 50 mph but the lower end of the engine has not been touched since new 42 years ago. And then, from a lot of research on this forum a few years ago we decided that we had to remove the deck and change the tank, even though we have no evidence of tank leakage -- the safety issue is there. We now have to stop thinking and start doing. As many of you know, prior to starting such a task there are many basic decisions that have to be made:
1) how original do we want to keep the boat
2) power and drive, chevy vs ford, merc vs volvo
3) speed performance
etc. etc.
We have decided to keep the boat as original as we can. Even down to reusing as much of the H&M labled parts as we can. That means we will go with Ford pwr and a Volvo drive (probably the 250 that is now on the boat).
I have been doing some new searches on the site to review lots of the past articles esp the ones on deck removal. Scary stuff but the info on this forum will be priceless --- so I will have to donate some more to assist with the costs of this valuable resource. We will not measure up to the level of excellence some (like George Carter) of you provide but we want to do the job as well as we can.
My first questions this year (don't know how long this will take) involve the engine. Our current thinking is to use a new crate engine (not even sure what the term "crate" exactly means in this context). We want an engine with heads that we can buy rather than rebuilding our engine. New would be best but I guess rebuilt is possible. Horsepower is still open, the current engine is the H&M 302 235hp pkg. I believe H&M just purchased a Ford truck block and marined it. The exhaust and intake manifolds have H&M logos on them and we want reuse them. (I realize the exh manifolds are not the best but we want to try to duplicate the boat when it was new as much as possible.) I also want to reuse the water pump, and thermo housing, plumbing from H&M as much as possible. So now the questions:
1)If I want to bolt all of these old parts on the new engine, what choices of engines do I have -- will all 302's for example accomodate these parts or do I need a certain vintage/year model engine?
2) And likewise, will later model heads for the 302 accomodate the H&M intake manifold from this 1969 engine?
3) Do the 351W engines have exactly the same bolt patterns for these parts as the 302 engines do? Is there any reason we couldn't use a 351W and still use all the H&M components? (Other than our quest for originality might favor the 302) Will the 351 fit under the hatch OK, engine height the same?
4) Any suggestions on specific engines, year models, and sources?
Again, while we would like to step up from the 235 hp and find a solution that provided 300+ hp with reliability--- keeping the H&M flavor is most important.
Thanks in advance for your comments and guidance. I have added a couple of pictures. Ed