If you're planning on adding p/s-a/c you want to hold onto the 2 groove balancer. A freshly modified 250 balancer set up with 2 grooves will run you better than $200.00.

You didn't mention what your fan diameter was but it might be less work to reduce the diameter of the fan you're running...if by chance you're running a 17".

Don't know if this will apply to your 261...but on my 1960 235 I cured all my cooling issues with an adaptor plate and an early 216-235 pump. I tried the "short-pump" route and had the same interference issues. The water pump adaptor plate moves the fan up to the top of the radiator which provides better air flow, gives me adequate fan/radiator clearance and with a 5 blade fan, clears the pulleys and my engine runs at thermostat temp even with the a/c.

If by chance your 261 has a similar setup as the 235 you might want to correct your current and potential cooling issues so that when you add the p/s and/or A/C you won't have to backtrack. I've got a fairly detailed photo documentation of the adaptor plate install in my webshots "shoebox" album. Hope this helps.

Dave

Webshot "Tips and tricks" and "Shoebox" Photo Albums

EXPERIENCE is the best teacher...but it gives the test first...and the lesson afterwards.

"What this generation tolerates...the next will embrace"