What 4 bladed propeller will fit a 1979 Johnson 70hp outboard?

Question

This is what I found. But is it the right size, pitch, etc.?

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=014&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=330148288174&rd=1

Answer 1

The right prop is critical for speed, economy, and durability. There is no formula to figure the right sized prop. You must have a starting point. The idea is the right prop will allow your engine to turn the proper RPM at WOT. Look around for a prop shop in your area, they will be able to provide the most help. Tell them what boat you have, what engine you have, and what prop you were running.

Answer 2

Unless yours 70 is on a flats boat or some kind that requires a instance hole shot than stick with the 3 blade.it has a faster top end.But if you want 1 you will have to drop 1 pitch on the prop for the extra blade or you will lower your top rpm .unless your over your top rpm know

Answer 3

go here
http://www.propmd.com/
find your original prop and pitch using the numbers on your current prop.
if you're happy with the performance - stay with the same pitch
don't go up or down more than 2" of pitch. more pitch = slower hole shot + higher top end but lower rpm @ wot
less pitch = opposite
make sure you have clearance

a 4 blade prop on a 70 is a bit of overkill......