i have a 1970 Chrysler 318 marine engine. i am going to tear it down, and rebuild it this winter. i need to know what components to use. (cam, intake, heads...etc.) i am interested in the 400hp build up described in this magazine. problem is, i need low end power for my boat, (pulling skiers) and the 400hp built engine doesn't start to make respectable power until 3,000 rpm. also, i am not sure if my velvet drive 72C can take 6,500 rpm? does anyone have any input. any suggestions would be appreciated. Thanks. Andy.  

Try a smaller cam and a dual plane intake.
A cam with power from 1500 - 5500 is closer to what you would need I would think. Something like a Crane cam for example, a 272/284 (@.050 it's 216/228) on a 112 c-line. It has a low lift of .454/.480.

I have no clue about the boats handling capcity though, sorry.  

I have a 68 dart with a 318 and have read about alot of things to do to the 318 to make it a light performer. I have the performer edlebrock intake edlebrock 600 cfm carb 1 5/8 hooker heads 2 1/2 in exhaust and I just aquired a set of 318 heads with the 1.88 1.60 valves from a local performance machine shop there open chamber but for the price I thought they would be good for what i am after. My question is this I ordered a comp cam the 470 magnum cam, its not what i origionally wanted but they said it would work for what i would be using my car for. After getting the cam i have done some reading on it and Im not sure if my stock pistons are high enough compression for this cam. I wanted an equal to the 340 cam for my 318. I called them back and they told me to Just get a higher stall converter. Is this cam to big. Or will it work for now till I get a torque converter  

I really don't like the center line and for you I'd rather see 112cl other then that the cams alright it's a single pattern cam with no more duration than a stock 340 cam, and the @.050 dur is also light 224* compared to 229* that the crane 340 blueprint cam has which worked great in a 318 I had with low comp pistons.
The 340 cam takes into consideration the heads are 'stock' more lift for the weak
[in stock form] exhaust port of that particular head.
Your heads sound like they have been 'prep'd'  a lil so a sigle pattern cam should work fine, however as with the stock 340 cam you will need some gears 3.55-3.91, if auto 2200 stall min is what I recommend.
And install it 106-108cl depending on the gears/converter, you might need to compensate.  

thanks for your input I have'nt installed the cam yet I was just hoping I would'nt have any problems before i did. Do you think it will be a dog without a higher stall converter? I am wondering because i will probably run it that way for a little while as funds are'nt always available for the project. Your input is greatly appreciated.  

At least have the gear and you can slide without the converter.
But be on the high side of the recommendation 3.73 maybe even 3.91  

this may be a stupid question but how do i tell what gears i already have? The axle was taken out of a 72-or73 satallite i found in a junk yard and had narrowed to fit mini tubs.I think you turn the drive shaft and for every turn of the drive shaft the tires turn so many times but not exactly sure of the rotation numbers how many time do you turn the drive shaft is it one revolution? I do have one more question if you dont mind, when i had the axle narrowed the guy removed everything and when I picked it up he told me i would need to set the preload? and check the backlash? Ive tried to find out on google but have really had no luck.If there were no shims removed would i need to do all of this if nothing really changed other then the removel and reasembly of it all. Once again thank you for your info. Ive been trying to find answers to my questions as this is my first try at actually fixing up a car and i would like it to turn out.  

I forgot to add the axle is'nt a sure grip its a 8 1/4 I know! its not the desirable 8 3/4 and it's open. I saw on craigslist a fellow has a sure grip for a 8 1/4 and i am interested in it but once again i am not sure about the whole preload and backlash set up. So if i can find some info on this I can kill two birds with one stone as he does'nt want a whole lots of cash for it. But i will probably have to get some sort of shim package or installation kit for it if i go that route. Two tires spinning sure looks better than one!