lets talk force induction.
Thread Starter
Instructor
Joined: Jul 2011
Posts: 181
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From: Boiling Springs
lets talk force induction.
Well, I've been toying with the idea of getting a supercharger for my 72 SBC. I've thought about just getting new heads and getting the HP gain through that, but I'm starting to like the idea of going the supercharger way. Now, I probably would not run the boost up more than 9psi, but from what I've been reading that can give it a lot. Now my question is what would be a good company to buy from and what would I need to get to make sure I don't damage the motor. I'm planing on getting a better water pump and radiator (for both motor and trany). The motor has been bored out .030 and I have some 882 heads which have been decked on the motor. The Carb is a 670 Holley, but I'm not to sure what I would need to do to convert it to a blow through Carb. My big problem is that I don't know what the PO did to the bottom end, I'm not sure if its stock or if they replaced it with some beefier parts. I know it was rebuild like 20,000 miles ago. But beside knowing what cam and some of the other work done to it, i, I'm left in the dark. Would I be able to throw on a supercharger, or do I have to make sure I have forged components on the bottom end?
Burning Brakes
Joined: May 2009
Posts: 1,232
Likes: 6
From: Tucson AZ
St. Jude Donor '12
If you're planning to build a blown motor, IMO its best to start out with a purpose built motor. 9PSI is a lot of boost in a street run SC. You'll probably need a bit more than pump gas at that amount of boost.
Yes, you'll need blower referenced carbs for best results.
There are a few guys on here that know volumes more than I do - they'll chime in soon.
FWIW, I run 6-7 PSI on a small block and get 600+ ft/lbs of torque starting at 2500 through 6500. A range of 6-700 ft/lbs in a street driven C3 will put a huge silly grin on your face every time you go for a ride. (Hint: BFGoodrich tires don't smoke much unless you really heat them up)
Yes, you'll need blower referenced carbs for best results.
There are a few guys on here that know volumes more than I do - they'll chime in soon.
FWIW, I run 6-7 PSI on a small block and get 600+ ft/lbs of torque starting at 2500 through 6500. A range of 6-700 ft/lbs in a street driven C3 will put a huge silly grin on your face every time you go for a ride. (Hint: BFGoodrich tires don't smoke much unless you really heat them up)
Thread Starter
Instructor
Joined: Jul 2011
Posts: 181
Likes: 11
From: Boiling Springs
Yeah, I figured I would want to build the motor from the ground if I run a lot of boost. I guess I though that 9psi would be a safe low number. I would be more than willing to drop that down to 5 or 6 if it would be less stress on. The motor. I have the options of getting some world product sportsmen II heads for 250 that are ported and polished. They need some work done because they have two bad seats and three busted valves, but I work at a machine shop, so I know people that can fix that. I'm just wondering what I need to start doing to the motor so that I can run a bit of bust that can push up the numbers.
Race Director
Joined: May 2005
Posts: 10,674
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From: Millington Illinois
St. Jude Donor '08-'09
Any power adders need forged pistons at a mimimum but for anything substantial forged bottom end is a must. A stock l48 crank won't handle a SC for long.
Last edited by 63mako; Jul 8, 2012 at 04:15 PM.
Thread Starter
Instructor
Joined: Jul 2011
Posts: 181
Likes: 11
From: Boiling Springs
That's what I was figuring. I'm not to sure if its stock or not. Would the best way to figure that out, to take off the oil pan and check it out?
Burning Brakes
Joined: May 2009
Posts: 1,232
Likes: 6
From: Tucson AZ
St. Jude Donor '12
Additionally, forged or not, a small block crank with a standard single key snout will not hold up very long to the pulley tension.
For the same money you're about to spend on FAI, you might want to consider just replacing the engine with a large displacement crate motor. Supercharged engines are purpose built, cam, crank, pistons, rods, heads all come into play with pretty specific requirements.
If all people had to do was spend 5-6K and slap on a blower and away you go, you'd see a lot more blowers.
