Lets here some opinions. running about a 300 hit of nitrous maybe more do you think it needs a vacuum pump? I know it wouldn't hurt but is it worth the money? Or would a header evac system work fine? Any experience would be appreciated. Probably going to run the hellfire rings as well.

Cody

If the pistons are gas ported for it then yes. If not it won't hurt but you won't see a large hp pick up.

You won't see any huge hp gains but with a 300 shot it would be GREAT to have for figuring out the timing....

well I dont have pistons yet so and they are going to be custom so they will be gas ported if I go with a vacuum pump. I'm trying to stay on a budget , but no reason to be cheap now especially if its extra protection.

Yes nitrous motor don't like oil in the combustion chamber at all.

Gas ported pistons are not budget. You only need a vacuum pump when running low tension rings. Standard tension rings do not need a vac pump, even with NOS. You will need extra piston to wall clearance as well as extra piston to pin clearance and more ring gap.For every 50 hp of NOS I would retard the timing 2 degrees.
Here is a vid from 11 years ago. I hit a 200 shot 30 feet out in my Pontiac. I ran 11,40s on the motor and 10.30s spinning through first gear.
http://youtu.be/opPB-Ur48pM

Thanks for the response and nice videos. is that video is from sac raceway? If it is do you still race out there?

I only go to Sac to blow the rust out of the pipes. lol I bracket race at Sonoma.Seen these cars before.

I tune with a wide band 02 sensor and fuel presure.

Not every engine is the same. Some engines will not perform with standard tension oil rings. Sorry tried it and the engine was down on power.

Some combustion chambers require more timing than others. I ran a 300 hit for several years and once I got my head out of my rear end and pulled enough timing and leaned the tune the car performed like it should. If I was to share my timing setup some of the knowledge passed around here would say it would never work. Everybody on here can't wear the same size shoe.

To the OP. A vacuum pump is a great accessory to run. Nitrous and/or low tension rings are really complimented by a vacuum pump.

Leon