I bought and built my Baja 235 force last summer. The motor I had built now has 55 hours on it and runs good, but I'm thinking about a bit more power for this year. The motor is a 4 bolt main 454 that I had built with new crank, pistons, rods, rebuilt peanut heads with stainless valves, custom cam and a dual plane high rise manifold. At the time I had some builders from this site est. hp to be 400-420hp give the cam specs I had (don't remember them now). I'm running a 23 Mirage plus and can hit 5000 rpms. A bit more then I would like with this motor, but I very rarely run wot. Our day usually consists of 3400-3800 running.

As for adding the blower....we all want faster, but I'm pretty gentle on the motor and remote concerned with a faster cruise. I have been wot probably less then 5 minutes total in the 55 hours I have on the clock so that being said would my motor do ok with the addition of 5 psi? I know it's not a forged build, but I think it is a steel crank. I have done some research and some seem to suggest selling the 454's and get used 502's. That is an option but the thing that makes me nervous is what I'm buying and having to rebuild something that isn't as advertised.

Suggestions, life of parts, what's needs to be upgraded? I run a Holley red (or blue which ever is marine rated). Would I need more fuel or is that ok?

I tried a friends 25 pitch turbo and it lowered my rpm's down to 4500 and gave me a better cruising speed so I plan on getting another prop, but may wait until I decide about adding a blower. Again, more top speed is great, but I'm really looking for a faster cruise. Cruise now is 45ish at 3600 (ball park).

Thanks for the help and advice.

would not worry about the crank as much as forged pistons..those blowers work great...get ride of those heads...killing you...if you run oval run 781's, 049's something along those lines....

You will need a cam spec'd for a blower ,new heads would be good and piston's and more carb. You did not mention what you have for exhaust but if you are going to pump air in you have to get it out as well . A friend of mine runs a 177 on a 468 and it works great ! The only secret is that you need ALL the parts to make it work not just some of them . Good luck

if your looking for a blower,give me a shout.i have a 250tbs,w/1050 carb,plus blower pistons and good rods.

As the others are saying, you can do it but be careful. I can tell you for sure that a forged crank can handle 750- 800HP as mine does. The problem areas are as stated. Cast pistons r no good, rods are probably good for 450 or so and then you are taking a big chance. Heads are no good for the high flows and may lay down on you way early. I would go to 3.5 -4psi and not much more if you want it to last.
On another note, I just finished a 468 build that has 990 heads that flow out to 6800 rpms. Although there is extensive work done on them they are the best flowing my builder has seen to date for iron heads. You may want to shop for 088's or something with a bigger intake runner. I also ended up running Extreme duty valves, custom grind cam roller everything, and JE pistons, in the end the only stock parts are a forged crank and heads.
758HP @ 6800
I do have a ton of parts and some good rods that will handle 500hp no problem if you know anyone.
I WOULD STAY AT 3-4 lbs MAX BUT THATS JUST ME. Let me know if I can help if you decide you want a good spec to build from.
There are reasons you build a spray motor and blower motors a certin way.....

another way to go for a bit more power. heads-cam-exhaust. as striper said 781 or 049 oval ports. they are on ebay for 300 a set. the intake you have is probably oval port already and works badly with peanut heads. there are lots of $4k exhausts to be had here used for $2k. there are lots of cam recommendations on here. under 3 grand and you are at 450 or so. there are stories of cast flat top motors surviving blowers, but even 5 psi is a third of an atmosphere. turns 9;1 into 12;1.

Thanks everyone. I'm looking into parts right now. This new motor has less then 60 hours on it, but may pull it down anyway and beef everything up a bit for the blower.

Just giving an update.

I've started to collect my parts. I have a set of 781's that are getting 2.19 and 1.88 valves. Pocket ported, gasket matched etc. Ive found a set of exhaust I'm waiting to arrive and talking with a few people about different blowers. Will be purchasing the blower with in the week. I can get a set of probe forged pistons for a good deal through a local vendor/friend of mine. Probe ok? I'm also going to look for a blower cam to use with this build as well.

My last couple items are my crank and rods. The motor was built with a standard/standard cast crank and 3/8 rods. Are the rods ok with arp bolts and under 5000rpm's or try and change. How about the crank?


This simple head swap has turned into a blower rebuild....lol. I hope I can feel a difference with this build.

Thanks for the help and appreciate anymore advise!

don't worry. you will.

Ill bet that your intakes for the B&M blowers will more than likely be large rect port.

As for your prop situation, you said the higher pitch prop dropped your max rpm, but increased your cruise speed. Thats how it works when going to higher pitch, however, not really the right way to do it.

Just because you are cruising at say 3600, the engine will work harder, and need more throttle input to run at 3600, than it would with a smaller pitch, at 3600. So you may think your saving gas, easier on the engine, etc, but you're not .

The correct prop is the one that puts you at your peak RPM at Full throttle, trimmed out. Then, for gains in cruising speed, adding blades, or other prop tweaks can help cruising speed, but maintain wot rpm. Ive seen so many guys lug their engines down with big props, thinking "it cruises nice and thats how I mainly run at cruise". Thats bad for the engine, and the outdrive.