speed of old f302 vs 35 0r 38 fast.. with same power
 

i know some with a f302 dynoed at 515 apiece ( 1030 hp ) with trs drives running 65is on gps. the question is i seen 35's and 38's fastechs with twin 525 mercs running alot faster then 65.. why? i know its alittle more power but there bigger boats. is it because the hull design? the trans and trs drives? or weight?
was thinking about going to xr drives in my f302 and eliminating the trans. one less problem to worry about not afraid of moving the motor or redoing the transom. i really dont want to pay for kondrads either.
will moving the motor back hooked up to the xr make me faster since more weight will be in the rear and less power has to go thru a trans?

thanks!!!

I'd be a little suspicious on those hp claims. I bought the very first 302 in '79, after having the very first Interceptor. It was the show boat and still have the binder around somewhere with the fabric samples and such. Actually got first dibs and bought it right from Vic and the local dealer, as they wanted to use it for a few more shows, then they let me inspect and they fixed a few little scuffs before I took it that spring. When they brough that boat out, it was a big deal for them.

Anyway, it came with 330's, and stock it ran a solid 60-62. Remember, back in the the day, there wasn't much choices in props, but I had the cleavers tweaked a little, different air cleaners, and elbows for thru-hull, and with a light load, I could get close to 64 with a light chop. Ran it that way for a couple of years, and it was bullett proof.

I then had some 4-bolts made to just over 420's spec made up at some place that Gary Stuewe recommended, and it bumped up to around 72-74. He had a little Cigarette dealer on Rand in Palatine, IL way back when. Ran great for a couple more years until I sold it, and moved to Cigarettes. Those numbers were with a Nordskog, which was as best as you could get back then.

Regarding speed differences, no doubt the stepped hulls help alot. Also, the Bravos are more efficient than the old TRS's with the trannys. And, prop designs have made a huge difference as well, so they all add up. I will say that I think the 302 weighed a little more than the claimed 7,800 lbs, but it rode like a tank. Great boat.

My 84 302 sr1 ran 75 with 1000 h.p. through trs with transmissions.

maybe this other 302 with 1030hp isnt proped right. my 302 with stock 330's and trs is getting 50mph on gps with half tank of gas and 25mirage props!

The '79 SE straight from the factory was a 60mph boat all day long - That's a fact. Later, I saw a few with 370's that could do around 65, and 400's that would do around 70, give or take. A few got the notch that helped a little too. The Kaama boats did a little better.

If someone had a solid hull with 500's, like Bryan stated, he should definitely be in the mid-70's, or something's not right. Either he's got a seriously wet hull, or gained alot of excess weight some how, and/or the engine, drives, and props aren't up to snuff. I suspect a little bit of all of the above, but something definitely isn't kosher.

then why you think my tank (f302) with stock 330's is getting around 50 on gps?! 800 some hrs on the motors drives and trans. just getting worn down?

I'd definitely start checking into the motors. With 800 hours, it very well might be time for a freshening or replacement depending on your situation. Then check the weight. These boats are known to have moisture issues. From there its a function of walking through the running surface, props, etc.

how would i go about checking the boats weight? or moisture?
with a moisture meter where do i start checking for moisture just the transom?

Mookster take a look at my stringer replacement thread and see were all the rot can be. Basically if you can or can not see it.... it can be rotten. They really did a horible job on some of the years in closing off the wood so that water could not get into it.

audiofn cant find the section u have on stringer replacement. were is it at?

Hey Audio - How's your rig coming? Did you ever finish it? Any pics? I'd love to see how that turned out.

Mook - Like Audio said, Formula back in the day did a poor job of fully encapsulating the bulkheads and stringers. Worse, the drains going back to the bilge got clogged very easily and this compounded the problem. Even deck leaks behind that fuzzy headliner, would pool on the floor under the first step. I caught water pooling on mine very early on and watched it closely.

Anyway, check it closely. then take your trailer to a truck scale and take it off the hitch and weigh it. Then load the boat, strip all of your normal equipment and weigh it again, subtracting the weight of the trailer. See what you've got. The dry weight back in the day was supposedly 6,950 lbs.

Next, rent a good 6 foot square and check the running surface from the transom forward. The vintage trailers back then were pretty bad and if not properly adjusted could cause a hook to develop over time, which will not help efficiency at all.

Once you are sure the hull is sound, which I hate to say would a minor miracle, then do a leakdown test on the motors. At 800 hours, it's well past time. You're probably lucky if they are putting over 250-270 hp out at this point. Provided the hull is solid, I'd just yank the old 2-bolts, and get some decent marinized crate motors. Once you get that far, you will definitely need new props.

Again these are fantastic boats, and well worth the investment if you are starting with a good foundation. Good luck!

I have not finished it. We started to build a vacation home in maine and that has taken priority. We have a 311 and a 18 Donzi so I can get out on the water with those. I wish I had more time to work on it but not looking good for a while.