hi
I'm new to pleasure/power boating. i found a fun boat with some neat items and have a lot of questions.

the boat 83 well craft nova II 26'
twin small block gm motors (don't know the displacement 350-383) i have only taken the intake off of port motor to take a look. from what i can see ported heads roller rockers,Miami stainless marine headers,edelbrock performer intakes and 750cfm edelbrock carbs. i was told port motor made 419 and starboard motor made 423 on the dyno. (the boat has been sitting for some time and the previous owner didn't remember the rpm or have the dyno sheets any more)

it has arneson asd6 drives with 17"x6"x28 pitch three blade props on it.

with five people and light fuel load pulled 67 mph on the gps.

so lets start with the questions.

1 how much power can i build a small block na gm to run on pump gas dependably? (400-500 hrs) mostly cruising 3000-3500 rpm?

2 running @ wot (no trim tabs) it would run 61-62mph @ 4000-4100rpm then when i started trimming more for top end it would gain speed up to 64-67mph @4300-4800. after that i can keep pulling the drives and gain rpm and loose forward bite. i can get them to hum along happily at 5000-5200 with no added speed. i have not tried to spin the motors faster than that and not over 5000 for more than a minute
can it be over propped and what should be a safe rpm?
(i plan on pulling the motors this winter and adding power maybe 500 each?)

3 the props counter rotate with the leading edges in or to the center of the keel from the top. is there a pro or con to this as apposed to away from the beam?

any and all thoughts and experience will be greatly appreciated.

thanks ken

28 is a lot of pitch. what is gear ratio of the arnies? turning in instead of out is sposed to give stern lift, which tail-heavy novas need. hanging off the back the way arnies do, i don't think it will make much difference. you want more power, those motors sound pretty good. pull them and stash them in the garage. get other motors to build. either truck motors which spent their lives with anti-freeze in them, or better yet Dart blocks and do 427's. that being said, Novas aren't fast boats. yours rides well but very few Nova ii's ever cracked the 70 mph barrier. they tried all kinda stuff with the Nova III. put the Fountain-style step in the hull. Put the Velocity-style pad on the bottom. (not wide enough though). didn't make it any faster. made it bounce around like a back-bay toy instead of a true offshore hull, but no faster. you wanna go fast with small blocks, find a 27-28 Fountain or Donzi and hang those Arnies on a fast hull. unfortunately you either hafta redo the transom to put stock stuff in the Nova again or let the hull go cheap or scrap it. which always hurts. my recommendation is enjoy what you have for another season or so.

the asd 6s are 1.32:1 i got the boat cheap,it needs work that i'll do this winter. as for replacing the drives that wont be a problem there is only a 3" hole trough the transom to drive the drop boxes, it would need to be opened up to put some alphas on it. i will paint it this winter and see if i can't find a newer hull to run the asds on. if not it's fun to run as is. i don't think there is room to put a set of big blocks in there it has a 8' beam and the small blocks are close together.

thanks for all the info i've been looking around the net and found some info. i don't know jack about hull design but thought at 5600# it should run a little faster lol

A friend of mine has a 90's model nova II 26' with twin 330hp 454's. I'm not sure if the hull is the same, but with the big blocks it's so tight I couldn't imagine working on anything in there. He gets mid 60's out of the boat.

Even full roller motors should be propped to run in the 4600-5000rpm range when maxed out. It sounds to me like you actually don't have enough pitch if then spin to 5200 without issue. Having ASD6's on a Nova II is interesting enough to begin with.

If I where in your shoes, enjoy as is and put the Arnie's on another hull when you have the coin

The drop box arenesons turned in put the twin prop thrust line where they would be if the boat had staggered engines. It was revolutionary in the 80's. Dennis Ferrara rigged many fountains and Hustlers this way right from the factory. In the late 80's, using arneson drives and twin 632 cu in all aluminum engines he was able to deliver 100 mph 42 fountains, which was amaing at the time.

I don't know much about your boat, or what speeds you would have with standard drives. However, it would be my guess that you would be giving up performance to switch the set up you have now, assuming it is set up properly.

leave the arnesons on the boat,,the drives are bullet proof so dont let someone talk you out of them..heres a example,,im not 100% on the story but their was a member named geo that put a 440 cid procharged engine that made over 1000 hp then detuned it to around 800 for a safe number..he had this package in a 18'donzi and it was direct drive with no transmission..he went through several props,when he first ran the boat it went something like 98 mph which was fast but not fast enough,after doing some tweaks here and their like i said i dont know the whole story and will never know what tweaks geo did but he picked up a additional twenty something mph..

2:14 in this video,,this was 1/2 tweaked..
http://www.youtube.com/watch?v=7kg3zoGcrFM

The drives are staying with me the only reason they are coming off is when I repower the boat and get something else to put them on. I was just wondering if I could add a little power and pull the props dependably on pump gas.
I run the boat on Winnebago,the Mississippi or mishigan. It had the arnesons installed on the orignal build in 83 and has been in a shed or on a lift most of its life