Scott72

I have had lots of luck with CMI's. A bit expensive but I found they were really easy to work with when I had custom tailpipes made. Do you know what year the 330's are? Don't the older ones (early eightes) have the large oval port heads which can be worked? Not sure if anyone recommeded this, but I would pull an intake and check port size to help determine exactly what you have (read through the post quickly so someone may have recommeded this already).

XCAV8

Headers have to custom made for 33" centers so i'm at best 3 weeks out... and i have to measure them , so do i go with the bassett headers he had on the 540's??they are full water jacket headers not like the ones they are making today water injected...(he said he paid $ 9000.00 for them full polished stainless...
or do i get performance manifolds what the difference between good manifolds and full headers???

convincor

The $3000 he wants I don't think is to bad.
I don't think your going to get full use of them with the 330's, or what ever they may be. I think headers and blowers go together.
Otherwise I think manifolds are the way to go.
Stainless Marinemakes a nice set-up, but the two sets will cost more than the $3000.

Darkhorse468

xcav8

I'm new to the game to, and hears my 411: .40 over 454 to 468, Merlin Grumpy Jenkins SQUARE PORT assembled heads 310cc 280
stainless severe duty valves 1,300.00 pair assembled(No real need for aluminum...whats a few pounds on a boat) . Speed Pro 10.00to 1 coated pistons 600.00 a set. Nice Crower or Crane hydr. cam around .600 lift with lifters 125.00. Chevy marine high rise single plane manifold(2500-6500rpm) 300.00. Your holley will be more than enough for the rpm range you want(5000-5200)
This combo with a 780 prepped holley, Gill offshore set-up and an MSD ign. 500.00 running 38 degrees advance ran me alittle over 520hp. at 5250 rpm. The blocks are 4bolt cast crank and rods(hi perf. chevy stuff, but not crazy) that were polished and BALANCED
by the builder. Beautiful thing is, motors and carbs all done cost me 4100.00 each. The other beautiful thing is I can get close to 600hp. if I dare to go into small block land (6000+ rpm). The big nut is the exhausts. You can't make good power without good exhaust. TRS will handle it no prob(others in this cite talk about 6400rpm with small blocks all day) Prop it right and you should get mid 70s. I scored the Gill set-ups for BOTH motors for 2400.00
which is way below cost, so I sorta cheated. GOOD LUCK!!!

JohnJan

I agree with JimV that headers will not do much for your combination. I've run a 330 before and they are not 98lb weaklings as everybody would have you believe. My 2 cents is to do some research and find a hydraulic flat tappet cam that makes peak torque in the RPM range that you will be running most of the time. An Ultradyne 276/286 would be a great choice. The peanut port heads need a lot of work or find some Dart oval port heads with a dual plane manifold like the Edelbrock Performer. The Qjet carbs can be blueprinted and in my opinion are one of the best carbs for a boat. I used Brad Urbans Carburator Shop to do mine years ago but I'm not sure if they're still around. Jet Performance also does Qjets. Between heads, intakes and blurprinting the carbs you'll spend $2k per motor and get 90% of what the rich guys are getting from buying all the expensive stuff. Prop it correctly and you'll have a very reliable, very fuel efficient combination.

BTW, I have DUI ignitions and heartily recommend them as well.

ForrestC

I agree. If the 330s run well, go out and have a good time this summer. Worry about major upgrades and the headaches that go with it at some other time.

When the weather is good, it's all about up-time, not the extra 5-mph!!!

blue thunder

JohnJan... I did much of what you say on my twin 330hps. I am at the propping stage now. What would you suggest for a max rpm on cast rotating assemblies? Mercruiser says 4200-4600. I've been spinning them to 5000 with no problem, but am looking to move up a little in prop.

BT

PatriYacht

A friend of mine had a 24 Baja Outlaw with a 330. He used to run it wide open for 20 minutes at a time, about 4800 rpm. After 5 years he sold it. The new owner blew the Bravo once but the engine ran fine until I lost track a couple years later. I have never heard of anyone breaking a cast crank in a bbc. A few years ago in a car magazine, John Lingenfelter got 510 hp out of a 454 with large oval ports using hydraulic flat tappets, Holly 850. 500 hp is not difficult with a 454. And the bottom end seems to be good for 500 hp and 5000 rpm.

B.R.S.

I had Lightening build me a set of headers on 33" centers and have been very happy with them. I would recomend them to anyone. I also have 2 weiand excelerators and 1" spacers that 40 Scarab talked about that are just lying around taking up space. I was going to send them to a swap meet but if you are intrested I'll let them go cheap. Square port though.

delsol

Wow as always alot of 'advice' here!! Sounds like alot ton of different directions. You're 'rebuilt whatever they are are going to get you on the water quick, figure out if you like the boat and determine how fast you want to go ( which will change as you become more comfortable). Those logs are just that. Buy a used set of gils -- 40 scarab has some-- you can always sell them for the same as you paid next year when you build/buy your 502's. Save you're money and build something good, my experience is you have NO idea what you've got until it breaks!!

My 3 cents canadian!