Hey guys. Don't confuse these DIY owners doing conversions with incorrect advice.
When GM built the Chevy 6 cylinders, they manufactured different ancillary pulley systems with different spacing for different applications that included, alternator, power steering, air conditioning, smog air injection pumps, hydraulic pumps, and governors.
These engines were manufactured until around 2010 in Mexico and South America, some say later, but this is unconfirmed and based on what some self proclaimed experts have told me so don't think it matters herein, but thought I would mention it for all the haters that keep calling the engine ancient as they poke fun at a conversion that is rapidly gaining ground for obvious reasons.
For the typical automotive use, the engines had 2 types of pulley spacings:
1.) Pulleys with grooves spaced apart
The grooves were spaced apart to prevent the V-belts from rubbing against one another when driving 2 or more ancillary devices located on the same side of the engine.
If the belt grooves were not spaced apart, there is risk that the belts could rub one another when slightly loose, wear the sides out and fail.
To prevent this from happening GM developed ancillary pulley systems with the V-belt grooves spaced apart so the belts cannot rub.
2.) Pulleys with grooves spaced next to each other (spaced together)
The pulleys with the V-belt grooves spaced together were used in several different applications, but typically had the ancillaries on opposite sides of the engine where the belts would never run the risk of rubbing.
The other use for these pulleys was when only 1 ancillary was driven, usually an alternator on the left side.
I won't go into the different AC compressors and hydraulic pumps and so on, but will mention that I have manufactured ancillary mounts that will fit the alternator, Sanden AC Compressor, and Saginaw Power Steering Pump.
Guys who like to advise others, please do it with caution and not shoot from the dark when it comes to the 250 conversions.
Brian has RHD with power steering without AC.
He has the wrong water pump pulley with the power steering for a GMC truck that uses the first pulley instead of the second.
In over 20 installs, I have helped coach, he is the second person to experience this.
Everyone else with RHD was able to use the factory power steering and alternator mounts and drop their engine in and use them.
Am going to offer to trade a set of Chevy power brackets that will line up with the second belt and a water pump pulley to match his crank pulley.
Then he can continue with his bolt in, bolt-up conversion.
So please don't tell Brian to buy a different crank pulley as that advice is incorrect.