Thread: 671 on a SBC

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Just wanting to get some first hand experience tips so I dont spend more time and money than I need to on it.

The motor is a mid-70's 350 truck motor that has been rebuilt completely so its only got about 1300 miles on it.

Mainly I want the blower for the looks but the extra power will be nice too.

Thanks,

Robb

In the long run, it's a lot cheaper and easier to buy a packaged blower kit made for your engine from BDS, Weiand, or one of the others. By the way you didn't say anything about your engine, but blowers don't work well with anything more then about 8:1 compression on the street with pump gas..... Just another consideration...

Was definately wanting to purchase a complete kit, I hate buying parts from all over, its worth the extra money in exchange for my time.

Also, I know several people that have around 10:1 compression on FI cars and you just have to be careful in the tuning.

Like I said, most of it is for the looks, but any extra power is welcomed.

Thanks

-Robb

Originally Posted by Rat Robb

Was definately wanting to purchase a complete kit, I hate buying parts from all over, its worth the extra money in exchange for my time.

Also, I know several people that have around 10:1 compression on FI cars and you just have to be careful in the tuning.

Like I said, most of it is for the looks, but any extra power is welcomed.

Thanks

-Robb

I'd check with the techs on the compression ratio---An efi car makes a lot of fuel and timing corrections that a carbed car doesn't. A blower uses a lot of horsepower just to turn it, be a shame to spend all the $$$$$ and end up losing horsepower, or worse grenading an engine....

Originally Posted by Dave Severson

I'd check with the techs on the compression ratio---An efi car makes a lot of fuel and timing corrections that a carbed car doesn't. A blower uses a lot of horsepower just to turn it, be a shame to spend all the $$$$$ and end up losing horsepower, or worse grenading an engine....

Very true, nothing a set of heads wont fix i guess, lol.

-Robb

well the boost is were you can get in trouble if you do not run much boost you would be ok but there is alot to tune one in so with cast pistons and a hi cr you can have a melt down . should look at a way to pull timing out when it starts to make boost like the msd btm box i run this on my 548 it is 10to1 and makes 10 inch of boost works fine

I found a new Holley 420 Megablower on ebay for a great price, worth keeping an eye on.
Keep in mind a 10:1 motor @6 lbs boost results in an effective compression of 14:1!
A mid 70s motor may just be in the right range compression wise, 8 1/2:1 or so. But cast pistons and crank + 2 bolt mains won't take a lot of boost abuse as mentioned above.

Originally Posted by Rat Robb

Just wanting to get some first hand experience tips so I dont spend more time and money than I need to on it.

The motor is a mid-70's 350 truck motor that has been rebuilt completely so its only got about 1300 miles on it.

Mainly I want the blower for the looks but the extra power will be nice too.

Thanks,

Robb

The Blower Shop and BDS make great kits.

The car club I belong to has a couple of members running a 350 engine with 9:1 and 9:5 compression and there using a 6-71 blower but only running 4 lbs. of boost. Anything over that as Pat and Dave mentioned will kill your engine fast.

Originally Posted by chevy 37

The car club I belong to has a couple of members running a 350 engine with 9:1 and 9:5 compression and there using a 6-71 blower but only running 4 lbs. of boost. Anything over that as Pat and Dave mentioned will kill your engine fast.

Who had those numbers??? Gotta wonder if 4 pounds of boost even gets back to even for the horsepower loss to drive a blower????? They look nice, but when I put one on a car it's for GO POWER, not show!!!!!!

Dave I was thinking of my buddies(Dave & Pat) in out car club. They are both running 4 lbs. of boost and as you mentioned they are maybe getting about 20HP more at the most. They care about looks, not performance. Nice to have alot of money you can spend on just looks

My original plan this winter was to do a heads/cam setup, but I recently attended a rat rod show and fell in love with the blown rats.

Prolly end up doin my original plan and then buildin the shortblock with some larger dished pistons and strongers rods and crank.

Thanks for all the help and Im sure ill be askin more question as I'm new to the old school stuff

-Robb