Chris Craft Marine Power 305K Engine Replacement/Repower?

leegoldring

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Hello Forum, I have a 1980 Chris Craft Catalina 251 with original 305 engine and Paragon transmission; reverse rotation. I am aware that the engine has not been run for 3 years. If you know these installations, you know that there is approximately 1" between the pulleys and the bulkhead - know idea how anyone could perform even routine maintenance on these things. At any rate, I essentially bought a very sound hull (I love this style so I am going to make it work) and a nice Karavan 9000lb trailer - engine questionable. I am planing to remove it from the boat so I can turn it by hand and sort through it all.

What are my repower options for this boat and engine combination - many forum threads indicate that only a Chevy 305 or 350 will fit without modification. Assuming the manifolds are still good, how to I approach a repower? All of this of course assumes that I cannot get it going. What are my options? Thank you.
 

alldodge

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Probably need a bit more info before determination, but for guessing possibilities

If the cam is in good condition then can go the rebuild route.
Get a 350 and have a cam made for RH rotation
Get a LH 350 and replace the transmission with Velvet drive (don't know what gear ratio)
 

Bondo

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Ayuh,.... It was older boats than yer's, but I've seen some Chris-craft SBC motors that were cast For Chris-craft, with some really odd-ball features,....

Track down the serial numbers, 'n castin' numbers on yer block,....

As AD says,... There's lotsa options,... Depends on exactly what ya got, 'n which way ya wanta get there,....

If it's a standard GM castin',... a 350 or 383 might be just what ya need,...
 

leegoldring

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Thank you All Dodge and Bondo. What are some reputable sources for rebuilt marine engines - 350 RH?
 

alldodge

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Thank you All Dodge and Bondo. What are some reputable sources for rebuilt marine engines - 350 RH?

That's a tuff one. Some folks will build a RH motor but its by special order of such. Most good machine shop can build one, the difference is the cam, distributer gear and oil pump. Look up First Mate Marine engines and give them a call. Summit Racing sells them along with a few others. If you want to build your self I can provide a name of a custom cam grinder
 

kenny nunez

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Get in touch with Marine Power in Pontchula, La. #985 386 2081. Ask for Shawn. He should be able to tell where their nearest dealer is.
 

leegoldring

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Thank you for the lead Kenny, and I did speak to Shawn. He confirmed what everyone have offered as options.

Looks like, a long block or complete package are options. His firm can put a complete package together for $8K. All vendors are coming in at that price. Too much for me unfortunately to spend. Talking to a gent named Chris at Michigan Motor Exchange, a long block option using my heads and block if good is about $2200. If a new block, then an extra $500. I have a reverse rotation and he'll use my cam, etc. I believe I can complete the current engine rebuild for $5K. That price is doable for me, but I need to find a rebuilder closer to Orlando. Is my assumption that a rebuilder must be familiar with marine engines and in particular the reverse rotation requirement?
 

alldodge

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If they build marine motors, they know what a RH motor is.
 

kenny nunez

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RH marine engines have special front and rear main seals and the pistons are on the rods opposite of a LH aka standard rotation, if any engine rebuilder disagrees with that leave them alone. Needless to say you must run the engine BEFORE you re install it to check for leaks and final adjustments.
 

leegoldring

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Great advice, thank you. I really do want to stay local for obvious reasons. Regarding engine removal, for this Chris Craft, I see a lifting bracket on the thermostat, and two on each of the paragon mounts. What is best way to attach the chains/straps? Not sure lifting by the tranny is a good idea.
 

alldodge

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If paragon mounts means transmission mounts, then lift by those and the thermostat housing ring
 

leegoldring

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This has become a very interesting, but good challenge. I have not yet pulled the engine, all mounting bolts are free and I will get it out in 2 weeks.

From discussions with a local engine builder (they use First Mate remans), this casting number is a truck 305. The block casting number is GM 1406383 and you could confirm as well. So likely not the original Marine Power 305K in thie Chris Craft Catalina 251.

I suspect the current valve covers, which have the marine power decal for 305K and also one decal indicating a reverse rotation engine (literally what it says...), were simply shifted over to this truck engine. That indicates that it "could" be a standard rotation; a money saver.

I will get the engine out, remove the front cover and check for gear to gear vs timing chain set up to confirm RR or not. I understand there are also 2 rear main seals that would indicate RR, but I don't ever work "inside the engine" only with bolt on components, so not sure how to confirm this. My experience and knowledge is limited there for sure. I assume the current prop would indicate if RR or not, but not trusting that alone. Advice would be appreciate.

Another question I would like to ask the forum is, how does the current Paragon tranny limit my long block purchase options? For example, if it DOES turn out to be a RR engine, can I use a standard rotation option without modifying the Paragon? I also understand a prop change would be in order as well if converting a RR to SR. . Thank for any advice, and please ask any questions. Lee.
 

alldodge

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remove the front cover and check for gear to gear vs timing chain set up to confirm RR or not

Gear to gear doesn't mean RH motor, the LH and RH motor rotate in opposite directions. These gears work the same
55520311.jpg

as a chain and no gears in the middle

The Paragon trans will need to be changed inside to use a different rotating motor.
 

leegoldring

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I may have access to a running, freshly-rebuilt PCM 351W, the same engine I just sold on my last boat, a correct craft. The builder had a lien on the engine (has Velvet Drive 71C on it also - $4K. An excellent deal. The seller is a local engine rebuilder - very familiar with reverse rotation, etc.

I have seen posts by CC-John that describe his installation of this engine (cut stingers down by 2-3 inches, glass over), but cannot seem to contact him on the chriscraftcatalinaclub site - it looks defunct for some reason when I bring up the address. At any rate, do forum members have a viewpoint on the installation? Thanks again.
 

Bondo

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Ayuh,.... Goin' from a Chevy, to a Ford is a step backwards,....

Ford has been outa the marine biz for well over a decade,...
Parts are double the costs, if ya can find 'em,....
 

alldodge

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The velvet drive can run in either direction as is. The velvet does not need any modification, just shift the other way and go. You could use a LH motor and no need for finding or rebuilding a RH
 

leegoldring

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Any advice regarding keeping the log style manifold (requires pressure relieve valves) and risers versus using center dump style? Are they more efficient, and should I be concerned about height restrictions on my CC 251? I want to do it right and put the right cooling set up on the new long block.
 

alldodge

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Did find the CC cooling layout with pressure relief valves

Chris Craft Cooling.jpg
 

leegoldring

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Thank you for your responses. Your image, though showing a Q, not my K MArine Power engine, appears to be the same water flow layout. Unfortunately, the only forum member I have been in contact with that has intimate knowledge of a CC 251 repower, using the center dump manifolds is CC-John, and the CC Catalina Club web site has been down for about a week. Had a few private messages going with him on that site, then boom, no more site...
 
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