PDA

View Full Version : 16 Classic - V8 Owners - I need advice!



bjh517
04-25-2004, 10:01 PM
I put a new 350 Magnum MPI in my 1995 16 classic, replacing my old 4.3L V6. I also regeared the Alpha Gen II at the same time. I have been searching for the right prop. The best I have tried so far is a 4 blade Bravo 1 with a 26 degree pitch.

This prop really gets me up an on a plane quickly, once trimmed my GPS top speed is only 54.5 mph. I expected faster from my 300 horses.

My question is what prop / gearing ratio combinations are you running and what are your speeds? Any advice would help.

Thank You
:banghead:

Rootsy
04-25-2004, 10:11 PM
OK #1 what gear ratio did you go to? #2 26 inches of pitch on a 4 blade prop is waaaay too much prop even at 1.65:1...

if you are at 1.47:1 then you need a 23 pitch 3 blade or a 22 pitch 4 blade... in the sub 15 inch diameter catagory

1.65:1 is gonna increase your pitch about 2 inches...

remember increasing prop diameter of the same pitch will decrease rpm too...

that motor wants to spin 4800 - 5000 rpm or so.. where are you at, i assume much lower than 4800ish if you are running that much pitch.

go for a 3 blade turbo 1 or a 4 blade hydromotive quad IV O/T to get some good running points with good speed... the quad IV is bigger than the O/T and much easier to come by used... but you'll give up a few mph.. the 4 blade hydromotives are very stable though...

where is your trim set for max speed? and are you dragging any tab?

bjh517
04-25-2004, 10:40 PM
Rootsy

I swear my mechanic said we went to 1.47:1 gearing - I will check tomorrow.
The thing that is freaking me out is that I am running 5400 - 5450 RPMs at WOT with such a huge prop! What is going on?

My old prop was w 3 blade 23 degree prop and I was scared to go WOT because the tach maxed out @ 6200+ RPMs.

I am so lost!

Rootsy
04-26-2004, 07:17 AM
What poodle said :bawling:

MOP
04-26-2004, 07:23 AM
Hmmm! Still set for 6 cyl take 25% off your readings, probably turning just over 4k.

Forrest
04-26-2004, 08:36 AM
The 16 doesn't need bow lift - especially with a the weight of a small-block Chevrolet in the stern - so forget about using using high-rake round-ear bow lifting props. Like Root said, the Hydromotive Quad IV O/T would be a good choice, but I doubt that you would be able to find one in the right pitch for testing. For that reason, I recomend getting your hands on a 3-blade Merc cleaver prop or two to try. Merc cleavers are usually easy to find cheap or maybe even borrow before you buy.

Rootsy
04-26-2004, 08:55 AM
if it's cleavers you want to test... ebay and screamandfly.com

there are a crapload in those two places...

and yes the O/T is difficult to find used... very difficult.. and new is 510 bucks...

and yes check the setting on the back of the tach.. make sure she's set on 8 instead of 6... Mr. Burton went through this with his swaparoo...

JR

Sam
04-26-2004, 12:47 PM
Last year I was running basicly the same set up as you have now. I ran 63-64 mph @ 4900 rpm spinning three blade Turbo. I tried several other props from cleavers to a Mirage Plus and the Turbo gave me the best performance. Just as a side bar note I may be selling my Turbo, I'ts a little to small for my SS. Also just as an FYI the Mirage made my boat act like it was on crack, to wild for me.


Sam :biggrin.: