Best props for a 312 fastech, small blocks
 

Needing new props for the 312, have 23p on it currently, What is the best all around prop for this boat. I have heard 28 pitch, four blade. Any advice would be appreciated!:cool:

My 312 came with 3 sets 28p 30p Lab 32p five blade. Running pretty big power. Havent tried the 28p yet. What kind of power are you running?

Props
 

I only have 350 mags in my boat. I wish I had your kind of power. Maybe when I need to rebuild them!

311 props
 

1st what do you want for speed / 2nd do'nt knock the S/Block's you can get them to do some wild things [383] stroked will get that moving with far less money then a pair of B/Blocks , try what you have now get the rpm /mph / how much fuel in tank how many people on board get as much info you can and post so blades or julie can get you to your best speeds :ernaehrung004:

Call Brett @ BBLADES 1(920)295-4435 he is the guru of props.

After talking to him and trying some different things, I ended up with a pair of 23 pitch Rev 4s by Mercury.
These are a 4 blade hybird between a round ear prop and a cleaver. Now this works for my boat which is a 1988 311. Gave the boat lift in the stern and i picked up anywhere from 6-7 mph on the midrange and might have lost 1 mph top end.

Brett offers a demo program which is awesome .... you can try different props without buying them .... this way you can get exactly what you want out of your boat ..... everyone has different expectations.

Good Luck !

Jeff

I had a 312 with 502's.....
Assuming yuou have a 312 with 300hp SBC and 1.65 Bravos then you would very likely need the 28P 4 blade bravos. If you currently have 23's on the boat it sounds like someone has been changing things around and likely switched the boat to 1.50 gear bravos???? More info is needed to help you.

1.50 ratio
 

Just looked at the drives and they are 1.50 drives

The 312 I have for sale has 28P Bravo 1's, 1.50 ratio with 454 MPI's which produce 310HP ea. Similar HP to yours.
It's a little slow out of the hole but not too bad.

Are you absolutely sure the GEARS inside the cases are 1.50. It could be 1.65 gears just inside a 1.50 case (I put together a spare that had a 1.65 case but we installed 1.50 gears in it).......if your spinning 28's anywhere above 4,800 I'll bet they are 1.65's.

(wish I knew the conversion for changing props/gears to tell you which set is appropriate)

I can't say "for sure" as I have never had them apart but that's what is supposed to be in there.
Why do you think they're 1.65?
Besides, the 454 MPI's top out at 4700-4800 RPM.

All the 312's I'm aware of came with the 1.65 gears...doesn't mean they didn't build them with 1.50's though.

With 415hp 502 mags and 385hp 454 mags they put 30P props on 1.65 bravos (I know of a bunch built like that anyway). When they put the base 310hp 454 in they dropped pitch to 28's.....based on that I figured a SBC set-up the same way should probably spin the same 28P props.........if it truely is a 1.50 gear ratio then the props would be smaller (like his 23's) but I do not know what pitch would be correct.

If it has the 1.65 ratio and 23P props it should be all over the rev-limiter!!!!

Since I owned a 312 this has me curious. Are you the original owner? Have you checked to see what is stamped on the side of the drives? Have they ever been replaced?