Hey everyone!

Well, as it gets nicer and nicer here in Idaho I've been out driving more. Bout time!

Anyways, I was thinking recently about a blown 468+ bbc (8-71, be nice to do a blown 496!) as a daily driver. I rebuilt a '67 396 back around the first of the year, and its still only got 2500 miles on it and runs great. But I have access to a 472" tall deck, not sure on price yet.

Any comments on a daily driven blown bbc, or people with combos? smile.gif

TIA

I haven't seen to many blown daily drivers... The only suggestion I would have is to underdrive the blower. I think that would be better ecconomicaly, and would prolong the life of the engine... I was at Kool April Nites last year, and the people in the motorhome next to us had this 68 Camaro SS, with a blown something... Anyway the day of the show, after it was over and we were back at our motorhome we could hear this popping sound... We didn't know what the heck it was, so we went outside, and the Camaro was pulling in, and it was backfireing and all that goodness because it was sucking in so much rain through the blower... That's something else to think about... You'd better have a backup car for rainy days...

Some of these plans sound good on paper, but if it becomes a reality, you'll relise how obscene that much power is, in a car you drive daily.

Figure that you'll have to drive in unfavorable conditions at times, rain, sleet, slow, ice.

If you Really want something you can drive everyday and have a wallet to build that motor, then i suggest you build a mild BBC with EFI.

I dont drive, and havent driven a car powered by a blown engine, but i do realise whats involved in building and maintaining them, and i dont think you want to put up with the maintainence scedual or fuel bill for something like that driven every day.

A blown motor, just like any powerful motor, is something that you're going to have to be constantly looking for signs of potential problems...not something that you can bolt together, fire up, and forget about.

Just my opinion...some people will claim that their 8 second car is streetable, however i hold a different opinion.

I know of one blown daily driver. It's a '71 Camaro with a small block and a non-intercooled Procharger. He told me he was running 20lbs of boost, and I didn't believe him until he took me for a ride and I watched his gauge from the corner of my eye. Sure enough, 20lbs, and he drives that thing EVERY DAY. He doesn't work on the car himself, and he has the money to pay others to do it. It wasn't a radical combo, either.

One thing I remember that he was going through intake gaskets pretty quickly. About two times a year, maybe more. I think the saving grace is the fact that he is rarely hard on the motor, he drives it like every other car.

IMHO the only daily driveable blown is EFI(maybe a carb, but EFI for fuel mileage) and a centrifugal. I pulled 23 mpg in a blown 93 Cobra a couple weekends back on a 500 mile round trip. FWIW

A couple of my opinions:

1. A 8-71 isn't needed. We ran a 6-71 and produced 1200HP on a 468 BBC. cast iron heads (slightly ported, solid cam, steel crank, forged pistons, chevy Mark IV 4bolt main block)

2. Since you are running on the street with carburetors, 7% overdrive is as far as you can go, I would recomend an enderle injection system. I prefer the look of it over carburetors and if you ever want to take it to the track you can jump up the overdrive (we ran 32%)and make some real power

A blower motor is like any other motor. You can build it mild, or wild. A mild one will live very nicely on the street. A wild one will only be happy at the strip.

Bill

Hardly see how 20 lbs of boost is mild

I never thought 20lbs is mild either (and I still don't). Alot of the import guys run 15-25lbs and drive those cars daily, too. I wouldn't do it, but it sure can be done.

Even a mildly blown BBC has tons of torque, and would be interesting (to say the least) to try to drive daily.

You *could* do it, as others have said, by building a mild combo, 114LSA cam, mild duration, smaller amounts of boost, etc.

The things that are going to make it tougher are cooling the thing in daily traffic (if you have to deal with that), rain (an 8-71 ain't gonna fit under the hood), and any number of other factors.

I don't doubt it would be fun, but if it were me, I'd leave the blown car for weekend jaunts, and build a nice stout N/A motor for driving daily. That one would fit under the hood, have probably just as good *usable* street horsepower, and be more reliable, even though a blower motor is usually very reliable if built well.

As much as I'd like to run my car daily, I think my neighbors would probably shoot me, and my gas bill would be bigger than my mortgage payment.

Recently, I found another fun way of getting that boost-bug satiated - I bought a turbo-diesel 4x4 to drive around town (and tow the 'velle). A V8 Diesel with 20+ PSI of turbo is a lot of fun to drive too graemlins/beers.gif

I ran a 283 (acttualy 301) with a 6-71 and dual 450 Holleys @ 6 lbs of boost. Never over heated, ran great and got 17 mpg on the highway with a 3.54 rear and a 4 speed Muncie.
I don't where the widespread myth comes from that Blown motors are hard to live with. those GMC blowers are run up to 1,000,000 miles in their original application!!
Be sure to use a forged steel crank and get it cut for a second keyway.

how much power were you making with that 283

Its not like I drive 50 miles a day in it now smile.gif Its more of a go run to the store, or to a buddies house vehicle. It gets started and drove atleast every other day, that what I ment by "daily"

Thanks for the replys so far though, waiting for a combo somewhere smile.gif

Give this guy a shout.

http://bruteforcechevelle.freeservers.com/

Jim

how much power were you making with that 283
Maybe 300 hp. But it looked pretty dern cool! Sounded like 800!

Those boost numbers on the gauge you are reading isnt "actual" boost. To determine actual boost you need an exhaust backpressure gauge.

As for the blown driver: I say do it. It all depends on what YOU want to do. If I had the money I would put a blower on my car that would be daily driven. I understand fully that they are different than N/A motors. They are more finicky.