double to single v belt?

I have a 200 with a double v pulley balancer and it seems hard to find double v belt pulleys in general my question is can you convert to a single v-belt pulley i am only running an alternator and a eaton m90 supercharger and would one v belt be strong enough to run the supercharger?

In word NO, the supercharger will require more power than 1 vee belt is capable of. A single vee running over the small blower pulley, even with a much wrap as you can give it, is probably only good for about 3kw, which wont be enough.
Id be keeping the 2 sheave pulley at least, and give consideration to using a poly vee arrangement, Blowers will genearlly need 6-8 ribs even at low boost.
hope this helps
A7M

could you explain the poly vee belt i dont know anything about them this is the first time trying to supercharge with a vee belt

I think he's referring to what is generally called a serpentine belt. A belt of a given dimension offers a fixed amount of friction, and this limits in the amount of power it can transmit before it slips. Going to a duplex v-belt (as you have now) increases power transmitting ability over a single v-belt, but the correct solution for a blower is a serpentine belt, which offers substantially more surface area than a traditional v-belt.

Serpentine belt simple referrs to the way they are used on a lot of modern engines, because the polyvee belt is so thin it can be bent either way, so drive can be taken from both sides of the belt.
The extra power capability comes from the fact that they have many vees, commonly 6-9, this gives good friction, and because they can be bent so much you can get high angles of wrap.
A old fasioned Alpha section Vee belt cant be bent backwards and isnt anywhere near as flexible as the polyvee, so it cant complete.
A7M

It will take an 8.75 adapter to the crank pulley and a 3.8 blower pulley for 6 psi and 3.4 for 10 psi and while your are at it, use an 8 rib to make sure you have no slipage, these #''s are good because I have done it with an m90. and mpfi, most talk about it becasue it takes alot of engineering and dollars to do a good set up. I know of only 2 or 3 that have done a good job at what you are attempting, your lack of knowledge of a serpentine style belt leaves me to wonder of your abilities to accomplish this. If you are truly serious, I will help you, If I had to do it all over again, I would use an e-85 set up blow through carb, because of the cooling affect of alcohol and no need for intercooler and the 105 octane rating and the amount of advance that can be run. Gas mileage will suck badly, performance will be beyond your dreams.

i am not unfamiliar with serpentine systems ive done 8 rib setups on mustangs it doesnt quailify me for this but i do have some skill any help would be greatly appreciated as this will be my first inline 6 build

What would you like to start with to accomplish this, is the m90 an oval are rectangular port, not that it would matter much on a 3.3 liter, if it had coated rotors and some of the coating is missing, it will not hurt much, if its no coating and alot of abrasion on the rotors it will need to be rebuild, it is actually quite easy, the easiest will be an aussie head and intake or CI head and intake, otherwise you will most likely need a 2 barrel direct mount on log intake and there are plenty of two barrels with enough flow and it will work well and make the stock head very efficient on the intake side. I don't know of anyone putting an m90 to a stock head, I personally think this could be very successfull with the better later heads with bigger valves, I think 275 hp with 10 psi with good other components is very easy. The bottom end is very strong and can be run with stock components using arp rod main and head studs and balanced rotating assembly. I even used stock pistons, as the small circumrence of stock pistons and there design are very strong, when have you ever heard a person say they broke a stock piston in a 200.

Heres what i got a 64 200 7 main engine with a 70s larger log head thats at the head shop getting the 2 barrel conversion and pocket porting valve job new valves springs (302 with dampner) viton seals etc, the carb i am using is an autolite 2100 1.33 venturi = 424 cfm my plans for this build is to mate this engine with supercharger to a 3 speed top loader and put it into my 67 comet 202 i want it fast as possible because its a toy but its not a track car if i can get the harmonic balancer made for a serp setup i may use the stock pulley the eaton m90 came with its off a 91 t bird with a bunch of miles so a rebuild is most likely in order, igot the intercooler and radiator assembly from the t-bird also. thats all i got going now everything is in the disassembly rebuild stage i found a place that a makes copper head gaskets for the 200 which i thought would be a plus and i got the double roller billet timing chain from classic inlines and i was planing on using arp bolts my only decisions now are cam and piston choices i want a clay smith dual pattern just trying to see what the best fit would be

I had bullet cams make a cam for me, if you call them, they probably still have it on file, my opinion is the cam is your most important choice and I think stock good name pistons will serve you well up to 10 psi boost and I have never blown the stock fepro gasket and a carb will allow you a little more boost than MPFI, because of the cooling affect, I see a huge difference by running 160 degrees with a good radiator, if you rebore, keep it to a minimum, I bored mine to .060 and it was a mistake with heat soak at times. www. siliconeintakes is a great place for plumbling your system at great prices, I paid to have a pulley to bolt to v belt balancer made and I think it cost me 175.00. One of the biggest things I learned is electric fans work terribly to keep a blown engine cool and I bought the best available. One gage I can give you to work off of is I ran 8.9'-1 compression and the most boost I can run on premium is 6 psi and only 4 degrees advance to have no worries, I think 8.5-1 should be tops, hopefully you can learn from my mistakes, I would like too see you build a helluva good ride, I do not have the knowledge to help you with your carb choice for blow thru, a holley 500 two barrel may have more support for tuning, in the end with being blown, make darn sure you are not lean, I had the ability to monitor everthing on a computer which you will not have.

Balldrick has put together the best m90 set up hands down period, this guys ride is as bad as it gets.

im going with the copper head gasket more or less to control the compression of the engine since they can make custom sizes and as a little insurance i have talked to balldrick but his setup and yours are beyond my budget since most parts i have scavenged or swap meet bought to save money any specs on that cam

i had thought about the dual pattern 108 lobe center cam

Umder( check this out) on the aluminum head section on the first page about half way down is a pick with a yellow cam card with the cam specs.

so broncitis when u said run an e85 blow through cab was there a specific car in mind or just upgrade mine to handle e-85 i would like to saty with the autolite for the atomizing affect