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Need opinions on prop choices

do not think you can get to where you want with that motor.

If you are going to invest all this money in a new prop and reduction then why not rebuild the motor to make some more power. Stroker kits are cheap and will be the least expensive thing you buy :)

you will not have close to enough power to swing a 3 blade SW
 
Forget about the concept of running 2,500 RPM cruise. If you want that you need to go to a 1:1 ratio (direct drive) and forget about running ground. To run ground you want to set your max RPM at max Hp, simple as that. Torque peaking a bit lower is perfect, that will give you throttle response, all of which improves ground running. But your cruise RPM will be up there (70-80% of max) since the prop makes minimal thrust at lower revs.

Honestly, given the specs cited, you have a motor built to run a low ratio with motor spinning to 4,500 or so. The gear and prop change proposed will probably improve things a bit (on both fronts actually), but won't get you where you really want to be.

You should seriously consider some motor mods before spending big money on gear and prop, 350's are the cheapest dollar/Hp value on the market by far. You don't cite a pitch setting on your present prop, but I would try taking some pitch out of what you have first and let her eat. 350 motors do their best work between 4000-5000 with easy mods and 5000-6000 RPM (and beyond) without breaking the budget. On a low budget ($1000) I suggest a Vortec head and cam mod. On a bigger budget start at the bottom end and build a lopey roller motor.

Once you have the motor sorted, then you can consider the best prop and gear.
 
Vortec heads have smaller combustion chambers so your compression will go up. The first thing is finding out what pistons are in the motor now. Dished pistons to keep the compression down for cheaper fuel. Flat tops will definitely require high test and you can't use dome tops. It also requires a different intake manifold, either a cast iron intake off a carbed marine Vortec or an aluminum Edelbrock etc.

When you put the intake on, take care to use plenty of sealant along the top of the block front and rear. I just got a full roller vortec 4.3 running on my buggy and had to pull and re-do the intake because I didn't get that 1/8" gap sealed properly. My fault, I did the same thing 4 years ago and had forgotten that lesson.

Same exhaust will work on the Vortec's. They are designed to operate to 5,000 RPM and will normally get you ~30 Hp more (although you are not getting full use of what you have at 4,000 RPM).
 
Use this product for your intake front and rear areas. It is not likely to push out if your crankcase pressures are high which is a common issue in high output engines. I run 2 breathers on my 406.
https://www.permatex.com/products/gasketing/ultra-series-gasket-makers/permatex-ultra-grey-rigid-high-torque-rtv-silicone-gasket-maker-2/
 
I like the Right Stuff myself, use it on all kinds of stuff. My preference for it is that it is the hardest sealant to remove of them all because it seems to bond to metal so well. The only places I don't use it is on items that I plan to take apart regularly or for high temp on the heads etc.. Never had it fail.

My issue with the intake sealing is a simple matter of not using enough in the first place. The Vortec intake leaves a 1/8" gap so you have to use a lot. Like I said, I learned that lesson 4 years ago and managed to forget it this latest round. Luckily I had not filled the coolant system, so the re-work was relatively easy.

https://www.permatex.com/product-category/gasketing/the-right-stuff-gasket-makers/

Also, I forgot to add, the best intake manifold gaskets are in the Fel Pro MS98000 T gasket kit (MS98002 T for V6). The intake gaskets in that kit are full metal backed to prevent failure, but you can only get them in that kit. So you end up with some O-rings to throw away.
 
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