I have a 10 meter fountain with #3 drives. It has fresh 540 aluminum head motors built for blowers, but they dont have blowers on them. Runs about 85 MPH. The compression is only around 8 to 1. How much power can I gain by raising the compression up to around 10 to 1? and can I still run pump gas? Or should I just install blowers???? I want reliability. What would u recommend for a blower for a motor of this size? I have willys 950 CFM carb on the motor now and would like to use them on the blowers if possible. Any imput would be appreciated.

Adding blowers would be the thing to do with your compression ratio. Also the easiest thing too!

You are losing a TON of power. Add the blowers it would be the best option and far outweigh the gains of higher compression. You are right where you want to be as far as compression for the blowers. You will get hundreds of horsepower and you can run 8 to ten pds boost on pump gas with that set up. Keep your timing coservative with the blowers and they will live a long time. 30 Deg max. Ideally you should run dual 750-850's for best fuel distribution. An 8-71 will be perfect and a 10-71 would be better if it would fit. You can spin the 10 slower and create less heat.

Make sure your motors are built for the amount of HP you will produce with the blowers first of all!

I would throw 6 or 7 lbs of boost to those mills and run 4- 850 to 950cfm carbs.Best bang for the buck !
I have a set of low hr Blower Shop 8-71s if you need them,all they need is snout's ,I used the 8-71 snouts on my new Hi helix 14-71s.

I agree with almost everything here, but I think 8 to 10 lbs. of boost is a little much for pump gas without sacrificing some engine longevity. Be careful in this respect.

Wildwarrior, How much you want for the 8-71's How much would the snouts cost. Give me your number and i will call you about them, Thanks

Please send me an E mail as you have that feature turned off on OSO and mail can not be sent to you .
Thanks!
Glen

Increasing compression from 8:1 to 10:1 will give you about 6.5% more power all other things being equal according to this article - The Power Squeeze

I dont think I can send email because im not a paying member, im just registered. Im not real computer savy.