compression ratios ??

What's up, nice site you guys have here. I'll try and keep this as short as possible. I have a 57 Chevy with a roots blown smallblock that I've been thinking about switching to a blow thru carb set up. I'm currently running a 385, 4.040x3.75, smallblock with a 4-71 single carb blower and a alcohol dominator. The pistons that I'm running are SRP blower pistons that list as 9.8 compression with a 64cc head, which is what I have. The block was decked a little so the compression might be a little higher than that. The car has ran 10.0's at 133 with little tuning and I feel it has a 9.80 in it still, but I would like to change it around where it would be more streetable. I've been looking at maybe getting a F1R set up with a intercooler. I'm guessing I have around 10.0 compression, how much boost could I run on pump gas/race gas if I go with a set up like this ??

Thanks in advance for the help and if you would like more details about the engine just ask.




Matt

Welcome to the site and thank you. Do you have any pictures of this monster? Thats a pretty cool sounding car by the way. As for pump gas and a 10:1 compressing ratio the tune is very critical. I don't know about blow-thru very much so i'm not going to pretend to. On pump gas you probably won't even get the F1R into it's effiency range. 6-10psi depending on tune? However with race gas you'll have a real monster on your hands. Let us know what you decide.

Thanks for the compliments, I'll post a couple pics tonight. It's not much of a looker though, been in primer for years.

A little more info...the blower I'm using is a old Dyers street setup and it really isn't meant to be spun as fast I'm currently running it, 28% overdriven, and it's only making about 8-9 lbs of boost. The engine has 4340 crank/rods, Dart Iron Eagle heads with 2.08/1.60 and a crane solid roller blower/nitrous cam. I would really like to see low 9's out of this engine and I think it's probably possible with a blow thru. Running race gas is not a issue either, the car doesn't get driven much, I'm also assuming that upping the boost for race gas is just a simple pulley change,,correct??

One more question for you guys,, when does o-ringing become neccessary ?? I've been told several different things on this, some say 12 lbs, some 15 lbs and I've seen a few roots setups on big blocks go 20lbs and last all season, but I know that is over the limit and really pushing things.


Thanks
Matt

Well primer is an indication of a fast car and i've been a primer racer more than once. Honestly that sounds like a solid combo, and the iron heads should have no problem holding a gasket with good quality gasket and good ARP head studs. Everyone has an opinion and my opinion is that boost dosen't blow head gaskets, a bad or aggresive tune blows head gaskets.

As far as the F1R is concerned what ever pulley is on there to begin with would be a good baseline and I bet it will be bad fast if the tune is in check. I don't have a ballpark as to where it will be right off the bat but the F1R leaves all the headroom you'll realistically need.