9:1 compression and a blower with low boost
 

With a 540 with all the good stuff in side, Can I run a 250 B&M blower with 4-5 lbs of boost with out blowing head gaskets everyday ? I know cylinder pressure is increased with boost . With 8.6.1.compression I ran 7 lbs of boost with no problems in a 454 and a 502.Next question is If my dyno numbers are 575hp at 5100 rpms and 635 ft lb of torque what kind of increases could I see With the 4-5 lb pulley ? I also run gil offshoe exhaust would I have to upgrade to a cyclone or CMI type exhaust ?

Re: 9:1 compression and a blower with low boost
 

The Gil's will be OK, I would run no more than 4 LBS boost with 9:1 CR. Talk to Dean Nickerson as he has done many of these setups with higher static CR.

Re: 9:1 compression and a blower with low boost
 

I doubt that you'll be able to make 5 pounds with the B&M 250 on a 540 unless you're overdriving the daylights out of it. I think you'll be more than happy with 2-3 pounds, which will also be acceptable with the 9:1 c/r.

Re: 9:1 compression and a blower with low boost
 

Dave, there you go thinking again. Get back on the drugs and stop working so hard. :p :evilb:

Re: 9:1 compression and a blower with low boost
 

Sorry, Payton. I should know better than to think,,,,,,,,,
How you been? We should get together for a drink, maybe with Steve AKA Rampage too. Maybe even at Steve and Maria's place.

Re: 9:1 compression and a blower with low boost
 

I have a 420 blower running a little over 5 pounds with 9 to 1 comp. on a 572 ran the boat all summer with no problem. I think what will limit your boost is the size of your blower with respect to the size of your motor too much boost will create a lot of heat with that size blower. I wish I had a bigger blower like a 10:71 but I am trying to sell the boat.

Re: 9:1 compression and a blower with low boost
 

Boatman here are some pics of a 540 ci we finished in Dec. for a 35 here in Miami with the 250 blowers the customer had originally 454s with the blowers and wanted more HP and torque so we went with the 540s and ported a set of heads for him and set him up with carbs and hydraulic roller set up the engines made 788HP at 5400rpm and the torque was a flat line across the board from 780 ft lbs at 3100 rpm to 832 at 4400 rpm and coming back down to 785 at 4800 rpm the pulley I used was a part #155193 and made 5 lbs on pump gas carbs were 650 cfm double pump and pri 65 jet sec 67 with 4.5 power valves and 33 degrees of timing.

Re: 9:1 compression and a blower with low boost
 

I ran a 598 ci with 8.75:1 comp. and 9#'s boost all summer with no problems. I think may have been a little aggresive but that was the way my builder dynoed it and it worked fine. I am running aluminum heads which is suppose to help.

Re: 9:1 compression and a blower with low boost
 

The heads we used were a set of new GM castings the customer supplyed us with and we remachined the seats and the ports for the combo Sincerely Laz Mesa

Re: 9:1 compression and a blower with low boost
 

But what compression ratio are you guys running ?