Can I use a torque multiplier on the crank bolt?

[volvo 4 life]

I don't have access to a 3/4 inch torque wrench but I work at a Ford dealer that has a Rotunda 1/2 inch to 3/4 inch 5:1 torque multiplier. It seems to me that if I set my torque wrench to 70 ft. lbs it would end up being 350 ft lbs at the bolt so it should work fine right? What is the actual spec and what do you guys think? Thanks, I really want to get this belt done especially since I noticed there's a spot on the edge where it has just started to fray!

[v8volvo]

There's a Volvo wrench extension tool that is used for that same purpose, so yes you can do that, as long as whatever you end up using will fit inside the crank locking tool. Volvo's "multiplier" is just a wrench extension bar, you set your torque wrench to ~255lbs and it ends up at ~340 on the end. If you have something that will achieve the same effect, I don't see any reason not to use it.

[volvo 4 life]

Great! So I should be good if I torqued it to 350 ft lbs? That would be 70 ft lbs on the 1/2 inch side. Also, what is a good timing spec for an NA car? I've read between .95 and 1.0 mm of timing gives the best power.