SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: k_bruno on August 01, 2013, 10:35:05 PM
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So I'm building a 454 for my 1975 21ft hawaiian day cruiser with a berkeley 12jc with an a-2 impeller
I would like to get some opinions on the build
73 Block that is going to .060
73 049 113cc heads
20cc domed pistons.... Should net 10:1 compression
Isky 280 hydrolic flat tapet cam
Hi volume oil pump
Double roller timing kit
King mains and rod bearings .020 over
Edelbrock performer 2.0 manifold
800cfm holley double pumper... Kinda think I need bigger but would like some opinions
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So I'm building a 454 for my 1975 21ft hawaiian day cruiser with a berkeley 12jc with an a-2 impeller
I would like to get some opinions on the build
73 Block that is going to .060
73 049 113cc heads
20cc domed pistons.... Should net 10:1 compression
Isky 280 hydrolic flat tapet cam
Hi volume oil pump
Double roller timing kit
King mains and rod bearings .020 over
Edelbrock performer 2.0 manifold
800cfm holley double pumper... Kinda think I need bigger but would like some opinions
I would run clevite 77 bearings... just my opinion though... was told by alot of hotrodders they hold up better ..
Go with the 800.. if it doesn't work to your liking .. change it .. then at least you will know whether or not a 800 will work ..
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I responded to this at length last night but the outage killed it.
When I get to Long Beach I will sit down with a nice refreshing adult beverage and give you my opinions.
I wanted to say right away though, you are a long ways off as far as the parts list you have right now.
Also wanted to add, there is absolutely nothing wrong with King bearings, used for over a decade in the. Winged Sprint car and also in marathon whitewater racing.
I think you will find that it is just something that others are not real familiar with them and there are not as comfortable with anything other than Clevite bearings.
I will coment later on about why I disagree about almost everything else you chose as far as parts.
Incorrect cam, intake, carburetor and believe it or not, oil pump.
I will see if I can get you turned in the right direction, these are just my opinions, so feel free to switch me over to "ignore".
I will ask a couple of quick questions though.
What exhaust system, what are you going to be doing with the boat and what are your expectations?
GT
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I am going to be running exhaust logs with over transom... And I know the intake isn't the best choice but its what I have for now I am planning on switching to a victor jr and some 115cc aluminum head when I get the money together in a few months
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And I went with the isky 280 because that's what they recomended with my set up
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So I'm building a 454 for my 1975 21ft hawaiian day cruiser with a berkeley 12jc with an a-2 impeller
I would like to get some opinions on the build
73 Block that is going to .060
73 049 113cc heads
20cc domed pistons.... Should net 10:1 compression
Isky 280 hydrolic flat tapet cam
Hi volume oil pump
Double roller timing kit
King mains and rod bearings .020 over
Edelbrock performer 2.0 manifold
800cfm holley double pumper... Kinda think I need bigger but would like some opinions
People may have different opinions of what combination should be used. A couple of things come to mind, I calculate out more like 10.25-1 compression with 113 cc heads and 20cc dome, and would encourage you to run more like 9.5-1 compression max with a heavy jet boat like that. The 280 cam would work, but probably not the "best" choice. I put a used one in a budget motor (468 cu in)that went into a jet boat, and was run on the dyno at 517 HP, so it was not terrible, but cam selection is based on your total combination, as GT Jets indicated by asking what exhaust you are running.
You should not need anything larger than 800 cfm, assuming you are still going to run an A impeller and be running around 5000 rpm, a 750 is probably a good choice.
I have never tried King Bearings. I know they are cheaper, but build a lot of real nice (read that "expensive") engines, and Clevites have never failed me, so I tend not to sway my choice of engine bearings, with the exception of using Durabond cam bearings. Once again, no issues with them in many, many years of them in many different engines.
I do like high volume oil pumps(virtually every engine I have built in 20 plus years), but my bearing clearances are set up to work with them, as well as using larger than stock oil pans. My engines do not experience bearing or oiling issues, and I have made a few phone calls to the tech department at Mellings to discuss and confirm my combinations.