gsxr1216

your not gonna make 450hp with that Qj, and stock manifolds IMO. what are the cam specs, that drives a lot of your potential HP also.

FWIW my motor makes 110+ hp more than it made last year and i didnt pick up 8mph, although i'm still messing with some props. i may get the 8mph when everything is dialed in but honestly i never tested several props on the old combo so there probly was something left on the table with the old setup.

cp5899

iTrader: (1)

I've got a few props to choose from. I have a 21 and 25 mirage plus, rev 4 22p.

Thanks for the info guys. I'll have it running in a week or so and report back on what it does.

jeffswav

If you are only shooting for 450HP, stick with the plan. A 454 with roller cam and peanut ports should get you there. Just be carfull with stock exhaust and the cam. What are the specs on that cam? If its a performance cam most likely you will get reversion, I did not fun.....
Figure about 1mph per 15hp on average.

Baja226sport

iTrader: (28)

Baja 235 takes alot of power to get moving! (Not as much as my current tanker...but these aren't race boats) None of the force hulls are fast. I saw a 265 recently with 900 hp in it near by claiming low to mid 80's. Most are getting that with 600hp! I have owned a few force hulls as well as a 24 outlaw which still takes alot of power to really get going! Stock 330hp is probably 55-58 mph.

Not saying anything is wrong with them, these are just old, heavier designs. They do ride really nice for their size because of this though!

A nice cam, and intake will help. I would junk the quadrajet in favor of a holley 750 or 800. Maybe skip the expensive heads and look for a nice set of gm rectangular ports with roller rockers and spend the extra money on aftermarket exhaust.

Then you should see your 450hp you want and that boat will be in the mid to upper 60's.

In that hul size/design/weight I have found that it takes about 100-120hp for a 10 mpg gain.

jeffswav

Yea, pretty good info. If you raise the x dim up the boats really free up. I gained 3-4 mph with a 3" raise.

cp5899

iTrader: (1)

X dim?? This is a new term for me.

450 wasn't my goal, but I figured it was an easy goal with a bbc with heads, cam and intake. I will start to look for holley 750.

jmaxness

Unless you change the exhaust, i wouldn't bother with the heads, won't gain a thing.

Just my 2 cents, been there, done that on a BBC.

wowchad

PM your email address and I'll send you a copy of a really good article about upgrading this same engine.

Over the last couple years I bought everything to do what you're looking at, but then I found the new boat I sold everything off (including the old boat with the 454) and I only have the carb and intake left. New boat is a 350 Mag so of course I didn't need any of the BBC stuff. Chad

gordyd4

You can't go wrong with RPM heads. Add a nice cam and it will be money well spent.

jeffswav

I raised my engine and outdrive up 3". A lot of boats were set up with the drives too deep. Raising them up gains you speed. If you go too high you will increase prop slip and you will not plane off. You have too find the sweet spot....