alpha 1 gear ratios?

[jopes]

Been reading about ratios, and it sounds like the 5.0/5.7's use a 1.5:1 ratio. I checked my outdrive and it is stamped 1.65:1. will running this ratio with the correct prop to keep the rpm's in the operating range hurt anything over time?

how much does it change the way the motor operates with the 2 different gear ratios?

 

[Tail_Gunner]

Re: alpha 1 gear ratios?

The answer is yes, a 5.0 does not have a much tourqe and horse power that a 5.7 does....1.65 is good middle ground for a 5.0

 

[achris]

Re: alpha 1 gear ratios?

1.65:1 is the standard ratio for the 305 (5.0 litre)......

 

[jopes]

Re: alpha 1 gear ratios?

From the reading on here I thought they ran the same 1.5:1 ratios.

 

[Tail_Gunner]

Re: alpha 1 gear ratios?

No there not...Without getting into q big long dissertation the 1.65 give you more punch out of the hole....along with top end speed..Its a balancing act. Some may have a 1.50 but it costs them either in hole shot or top end.....

 

[Don S]

Re: alpha 1 gear ratios?

If you are changing to a 5.7 as you show in your signature, you want to change to a 1.50 for the 5.7. Otherwise, all the work to upgrade HP is wasted by using the wrong gear ratio and a steeper pitched prop.

 

[dan t.]

Re: alpha 1 gear ratios?

Well now that everybody has had their say I have actualy done this, I started out with a 305 2bbl alpha 1 gen II, 1.65 ratio, performance was lacking to say the least, Put on a 4 bbl, some improvement but would only swing a 16x16 prop with 4300 wot. Rebuilt a 350 mag and tweaked it up to aprox.290 hp I now run a 15 1/2 x18 prop with added cup, 4600 wot and goes like a cut cat, still 1.65 ratio leg. It can be done.

 

[jopes]

Re: alpha 1 gear ratios?

If you are changing to a 5.7 as you show in your signature, you want to change to a 1.50 for the 5.7. Otherwise, all the work to upgrade HP is wasted by using the wrong gear ratio and a steeper pitched prop.

Yes I did upgrade to the 5.7 thats in my sig. I am still on break in so I am not sure what prop I am going to end up with. I do sit at 4800 ft elevation so I know some power is lost from that. For now I will have to deal with the 1.65 ratio as the money is done for the project, when the out drive fails I will bolt on a 1.5 ratio and go from there.

 

[Don S]

Re: alpha 1 gear ratios?

At 4800 ft, you are border line either way.