chris-jack

In my Baja 320 I have two good stock 454 mag. engines with about 200 hours on the clocks. They run well but anyway I want to updrade them for more. What would you buy if you do not want to invest more than 5.000,-/engine.

(I hope everyone understands my "perfect" english)

Perlmudder

exhaust, cam, heads?

stevesxm

i bought 2 - late 502 mag mpi takeouts w/ less than 100 hours on them for 4000 each. and was very happy with the result.

installation was a piece of cake with only a lift pump to supply the high pressure pump additional required.

rssteiny

I would try to trade yours in and get 2-- 500 hps from one of the engine builders, lots of them on classifieds here on oso. but you will need bravo 1 drives or better to run 500 hps.

Griff

Also add carb and intake. More than likely you will have to skip new heads and go with some mild port work on the ones you have to stay within budget. It really depends on what exhaust you go with. Exhaust could vary from 3k to 6k depending on what you get.

chris-jack

Good idea.

what are takeouts?


I have bravo 1, but I want to stay under 10.000,-!

KAAMA

iTrader: (1)

If I remember correctly, those are the Merc 365hp engines with the old rochester quadrajet carb....correct??? If so, it is a very solid engine with all forged parts...i.e. crank, rods, pistons. So, you're good there.

Do you plan on tearing down and totally rebuilding the engines??? 200 hours isn't much time---perhaps just add a cam without taking the entire bottom end apart.

If you're real serious about making more power, then the FIRST item you need to buy is a better breathing aftermarket exhaust system---something like a Stainless Marine exhaust system would be great.

If it is the Merc 365hp engine, then it should have the stock GM rectangle port heads which is good enough for what you're doing. You will save a lot of $$$ money by keeping the heads you have now---just have them checked out and do some very light/mild bowl/pocket porting and shortside radius work by someone who KNOWS what they're doing---no necessity to do anything major on the port work otherwise you could kill the power, add bronze wall valve guides, make sure the decks are FLAT and a fresh valve job.

&) roller rocker arms
&) Holley 750cfm carbs
&) single plane intake manifolds (only if you add a cam and aftermarket exhaust)
&) hydraulic roller cam, roller lifters and matching valve springs, moly retainers and 10* machine hardend locks, and make sure to check for piston to valve clearances

If you do all of that---then it will make a BIG difference with your boat, but you will need to make some prop changes as well.

For what you're doing, I would call "RMBUILDER"/Bob Madara of Marine Kinetics in N.Y. (585) 654-8583 and let him get you dialed in with the correct cam and valve train components as it relates to what you're doing to the rest of the engine. He is a wealth of knowledge and has helped many here on OSO including me. Have fun!

KAAMA

iTrader: (1)

This is just an estimate...

aftermarket exhausts $4500
holley carbs $1000
intake manifolds $700
roller cams, lifters, springs, retainers, etc. push rods, $2000
roller rocker arms $700
head work---porting, valve job, bronze guides, $1000

You're going to be very close to $10k in parts and some labor...and I am not counting all the labor you will require for your project. You will probably save about $1200 or so by going with a flat tappet cam verses a roller....but flat tappet is quickly becoming very old technology these days. Everything is going to roller stuff now.

Another thing that will effect your project is whether or not you have your engines completely torn down (bottom ends), machined, (honing the cylinders with torque plates, squaring the decks, align honing, etc), rings/bearings, ARP rod bolts, cleaned and assembled....that will be even MORE money.

Like I said, you may be able to just add a cam without disassembling the bottom end, but I could be wrong about that.

Just make sure whoever is doing the machine work, assembly, etc, has a very good reptuation. You need to be able to really trust the machine shop guys with what you're investing into this engine project. Most of what they do and how they do it will determine success or failure.

KAAMA

iTrader: (1)

Also, here is an idea....

Buy some of the major external stuff this year....like the aftermarket exhaust and maybe the holley carbs and add them to your engine now. It will keep you boating this year....plus the exhaust will add some definate KICK in the midrange and will sound good. You may even gain a little RPM on top.

Who knows, maybe these mods alone will make you happy enough for a while until you do more mods when disassembling your engines for a total rebuild.

You can always buy the rest of the mods stuff next year or whenever you decide to rebuild the entire engine during the off season....heads, roller cams, intakes, roller rocker arms, machine work, etc...

chris-jack

Hi Kaama
I thank you for the time you take and for the ideas you give to me.

As you said in your last tread, I think, this is the way i will go, because it is a new boat for me and I first should check if i want to go for more or i am happy like it is.

I put a full fresh water cooling system this winter on my engines and had the stock exhaust off. so i saw, that i will have to replace it this or next year. But i do not want to go again for a stock exhaust. i like the dana with the silent vortec risers. I need the silent ones, because i dont live in the states, i want to drive on the danube through vienna and this i can only do with silencers. (Maybe the boat show is the right time to buy them.) What do you think?

Is the Quadrajet a good one or does it really make sense to go for the 750 holleys?

I read here on OSO, that somebody said, the stocck 454 mag is a good base for a blower. My idea: Why not putting a Weiand Blower on it, i could get it for about 3k.(ea.) it makes good hp and including the danas, i could stay beyond 10k.