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Thread: first engine need advice

  1. #1
    Ok i'm finally gonna start building my 454 it's gonna be my first boat motor and there is very little in the way of informative shops in this area, so I need to know what i want before i go for machine work.. Could someone help me with a few questions and recomendations.
    the motor will start as a stock bore 454 4 bolt main and will end up a 468 in a jet boat. I would like to build somewhere in the area of 550-600hp but this may change once i get budget figures together.
    1. what is the highest compression i can safely run on pump gas.
    2. will the stock crank and rods be ok with this power?
    3. now there seems to be a ton of differn't answers on this one but should i use aluminum aftermarket or beefed up stock cast iron heads?
    4. should i have the machine shop make any modifications to the block as far as oiling? or altering for anything else, i have heard talk of machining the block for o-rings?
    5. I would like to run a tunnel ram with 2 4's any good combo's you guys are running on a similar hp motor?
    and last where do you recomend i buy parts from? I want to gather all my parts take the motor/ heads/ pistons and rods to the machinist have everything machined then assemble it myslef but i prefer to buy the parts myself so they don't try and put some junk in.
    thanks for the any info

  2. #2
    first off you need to know how much cash you have and can spend on your motor,don't try to build your motor by buying item by item,it will cost you more !your profile says your in calif,thats good because some of the best engine guru's are in might call,greg shoemaker,wilkes marine,pfaff racing,teague marine,these guys will get you in the ballpark for are not the biggest cost,prepping,machining,setup do cost to have it done right.and most important marine engines are set up different than car engines!!!!!good luck.

  3. #3
    TAHITIJET, I would order your parts from JEGS. Go online and compair prices to a local shops prices, JEGS doesn't charge sales tax. The compression #'s have been discussed in forums many times. If your going to be running on pump 91-93 octane, I would try to stay at 10:1 or 10:5.1 . As for heads, I would run a good set of aluminum but, a good set of cast like MERLIN would work great also. Everything depends on how much money you want to spend. I would build a good bottom end with good set of rods and crank for a long lasting motor. Just to give you a idea of price I had my 454 completely redone by a local machine shop that I know the owner and he has alot of years boating behind his belt. For block to be comp. gone thru,balanced,crank and rods redone,new pistons to bump up comp. heads redone w/valve job, I bought new cam and ARP hardware from jegs and I already had MERLIN heads, It cost around 2k. for machine work pistons,head work,and assembly, so depends on what you already have for parts, most of these marine engine shops will charge you around 4-6k to do your complete engine, you may save alittle doing assembly yourself. I called all these shops HUFFPOWER said and I wasn't going to spend that kind of money on engine, and yes marine and auto engine's are set up different so make sure you take that into consideration when assembly comes. I would call DNE in costa mesa, this guy knows his stuff and works next to the world famous jet builder, Jack at MPD. Hope this helps and sorry for rambling, its early in a.m.

  4. #4
    69 Elim
    You guys mentioned that marine engines are set up differently than cars. What is defferent & why? Just trying to learn. Thanks for your help and knowledge.

  5. #5
    Brass freeze plugs, starter, distributors, & alternators that are sparkless, specially designed carbs that dump excess fuel down the barrels, cams with no overlap, high capacity oil pans, special waterpumps with stainless parts, etc, etc.....

  6. #6
    69 Elim
    Thanks for the reply, but I realize those differences. Is there any differences when assembling a long block? i.e. bearing clearences for different oil/water temp?

  7. #7
    Havasu Hangin'
    Everything Rivercrazy said, plus, I believe the (forged) piston to cylinder wall clearances are set for the cooler running enviroment.
    In general, marine engines need to build alot of torque, faster than a car engine. Also, since they are constantly under load, detonation is always a concern.
    Try a search (http://free.*** on the board. There's some good information somewhere around here...

  8. #8
    The marine engine will need more piston to cylinder wall clearance than a car. J&E recomends .002 to .003 extra wall clearance for a boat motor and even more if your running NOS or a blower. Merlin says to ad an extra .001 to the lifter bores on one of their new blocks, but shouldnt be nesacery on a well used stock factory block. The valve guides will also need an extra .001 or so clearance. The bearing clearances should be ok at the loose side of stock.
    The oil temp on your boat motor tends to run a little higher than in a car and the internal temp of the engine is as high or higher than in a car, but the the cold raw water running through your block and heads wont allow them to expand as much, so you need the extra clearance "built in" to keep everything from seizing up.
    Ask your machinist about marine clearances, if he doesnt seem to know or care about them then find another shop fast. Stock car clearances will cause problems and are not for your boat.

  9. #9
    69 Elim
    Wow, thanks for the reply. I am glad to hear about the differences. Also got a question on the new Vortec heads for small block chevys. They say they are not for marine use. Why? I was thinking they would be a good replacement for my old stock heads. I know about 64cc and different bolt pattern.

  10. #10
    I'v never heard of any reason, nor can see, why you could not use Vortec heads for marine use. I dont really follow what the new boat builders are installing, but I thought they had been using Vortec engines in several of the new marine packages for a few years now.

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