409 marine (boat motor/engine)

#43
BTW, what kind of horsepower do the later marine engines have? ( I'm told that the one I am interested in is a '64. It has an X on it.)
I'd like to get a power increase over the 348. Any guesses about what kinds of increases the easier upgrades like dual carbs and/or a mild cam will give?
 

427John

Well Known Member
#44
BTW, what kind of horsepower do the later marine engines have? ( I'm told that the one I am interested in is a '64. It has an X on it.)
I'd like to get a power increase over the 348. Any guesses about what kinds of increases the easier upgrades like dual carbs and/or a mild cam will give?
It depends on the 2 engines your trying to compare if looking to replace a high horse solid lifter high compression 348 with a low compression 409 with a hydraulic cam there probably won't be much gain maybe even a step back,but if your comparing it to a low compression hydro cam 348 then there should be noticeable gains.If your going to have to rebuild the engine before use by all means use some of the available higher compression forged lightweight pistons to get more gain and to build a solid foundation for possible future power upgrades.
 

427John

Well Known Member
#45
Another thing about the marine engines is that the horsepower ratings can be deceptively low due to the manufacturer basing the rating on the observed power at the rpm the drive is designed for which is typically significantly lower than peak power rpm.While I'm not familiar with the marine 409,I do know the 300-330 hp 427 ford marine engines as installed in chris craft boats will run rings around a 300-330 hp 390 ford when installed in the same car.
 

32witha409

Well Known Member
Supporting Member 2
#47
Chris Craft used to source the best performance mills for the period to put in their run about's. EG 1970 20 foot Volvo Penta out drive could have had the 302 FLV (310 hp), that's the DZ 302 in sheeps clothing. Also had a 350 FLV which was the LT1. I wonder if the 409 HPO engines were used too.
 

427John

Well Known Member
#48
Most of the Marine 409 engines were in the 270-280 HP range with solid lifter cams
I suspect that 270-280 hp rating was at around 4000 rpm though,theres no way an engine that big would be that mild with a solid lifter cam unless they used the super low compression truck pistons in them.I know the ford marine engines were around 9.5 compression or better the big truck and industrial engines were really low compression but they were specced to survive even in hot dusty environments,the marine engines had plenty of cooling capacity available to support a higher state of tune.If chevrolet was similar to ford in how they built their marine engines it wouldn't surprise me if their lower horse big boat motors were very similar to the 340 409 shortblock with maybe 333 heads and a marine specific cam.If this is the case I would expect an engine like that to make closer to 325-350 horsepower if spun up to higher rpms.If someone has had a marine 409 apart did they see if it had truck pistons or something more like 340 horse pistons in it?Also was the intake more like a 340 horse or a truck intake?
 

Don Jacks

Well Seasoned Member
Supporting Member 3
#49
While I can't speak for all 409 marine engines,over the years I've seen pictures of several.All of those used the truck/industrial pistons and the 333 head.Another reason for the lower hp ratings likely comes from the "suck egg' exhaust manifolds that they used.
 

BSL409

Well Known Member
Supporting Member 6
#50
While I can't speak for all 409 marine engines,over the years I've seen pictures of several.All of those used the truck/industrial pistons and the 333 head.Another reason for the lower hp ratings likely comes from the "suck egg' exhaust manifolds that they used.
These engines came with aluminum intake and dual point dist
 

rstreet

Well Known Member
Supporting Member 14
#51
427 John. As I recall a std marinized Ford 427 was rated 300 HP with single carb. I saw a few back in the day but don’t recall working on any. Back in those days in my area gas marine stuff was mostly Chrysler products. But we did have a few odd ball Oldsmobile engines marinized. But I loved those 2 cycle Detroit’s in any configuration!
Robert
 

427John

Well Known Member
#52
Yeah the 300 was by far the most common and was usually in bigger boats there were a few in smaller boats that had a rating of 330 but I suspect it was the same engine just geared to turn a little faster.The block,heads,intake,crank,rods & pistons were the same,the only things that may have been different could be the cam and carb but I don't think so.It was significantly more engine than the 300 horse 390 used in a lot of cars in the 60's.
 

427John

Well Known Member
#57
Was looking on a chris craft forum and confirmed my suspicions on the power rating of 300 was at 4000 rpm.The twin turbo layout on the daytona looks very similar to the seamaster 534 marine engine that used the ford 534 super duty truck engine.
Correction the twin turbo version was labeled the super seamaster 534,gotta love late 50's early 60's marketing.
 
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#58
Dang! That's cool!

BTW, I went and had a look at the marine engine this weekend.

It is a Daytona 400 (still has the stickers on the valve covers) and is pretty much all there except for the carbs and turbos. (I'm guessing that, if they had been included, those turbos wouldn't work in a car/truck. Doesn't look like there would be any room for the fan.)

I found the owner to be very forthright and happy to talk about every aspect of the engine as well as other car-related stuff.

As expected, it is a low compression block with 333 heads. He helped a friend pull it out of the boat that had just been driven up to the Bay Area from southern California, so it is known to be a running engine.

This guy has a boatload of experience with hot rods - pun intended. We talked for a while and he actually suggested that I might want to consider doing a rebuild on my 348 myself. When I was much younger, I did rebuild a couple engines, but now I would have a hard time finding space or time to do it. And, call me crazy, but, in my mind, a 250hp 348 just isn't a substitute for a 409. So I ended up saying I'd sleep on it for a couple days, and leaving without the engine.

Now that I have slept on it, I realize that I am really more interested in a stock or very slightly modified 340hp, 409hp, or 425hp engine. So I am going to wait until I find just the right one. I think the ebay guys are a bit out of my range but I have plenty of other stuff to do to my truck while I am waiting.

Any leads would be appreciated.
 
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#60
$5k

He has had the heads machined, but just did a visual inspection of the lower end and was satisfied that it was good enough for him to use in his own car. He has replaced the cam and has a new distributor. He has a new offenhauser dual-quad manifold to go with it, but no carbs. There are headers instead of exh. manifolds. Misc parts still need to be installed. Distributor, manifolds, etc but it is mostly assembled.

I asked him if he would like me to post it here, but he said no, he'll just hang on to it.
 
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