Wait until I win the powerball!

In all seriousness I thought I could upgrade to1471 and turn the 871s and have very little into it.

Baby steps .

Your top pulley is small but so is your bottom pulley, looks like you are not overdriven. You can overdrive 15% easily with no ill effects since you have a cooler. I also would be concerned with the bottom opening if it is the small delta (mixture distribution using carbs), not just the delta at one end. I switched to a 14 from an 8, not much difference really and I still own the 8. I just needed a bit more air movement with the new lower compression, larger CID and improved heads engine. You want to use the smallest blower that will allow you to make your target boost at 5 to 15% overdrive.

The discharge is just delta on the one end, not the full delta. Should have clarified that.

You are good to go then.

The size of the top pully being small doesn't necessarily mean anything. You need to know the size of the top and bottom pulleys together to see what your drive ratio is.

Here's a full chart of 8MM, 1/2", 12.9MM and 14MM pulleys. I run 9.4% OD on my 8:71's and have found that to be fine.

http://goodvibesracing.com/Ratio_Charts.htm

Yeah, quite familiar with ratios and correlation to blower speed. The lower pulley I believe is a couple teeth bigger, just can't verify because boat is in storage.

Dam! Just change the pulley to up the pressure to 12 and let it eat! LOL you rock rider

^^^^^^^^^^^^^^^^^^^^^^^^^^^if he cranks the boost to 12 lbs she will eat,eat pistons,lol.