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Me and my Dad are fixing up his old '67 Fastback for me and him to take to shows. The car has a 390. We also want the car to have some power but probably can't put over a thousand into the engine. Have any ideas to put a horse per cubic inch?
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What kind of power and torque does the engine currently have? Is everything is top functioning condition?
Cheapest horsepower per dollar is nitrous, but I doubt that is what you are looking for.
Engines need air, spark, and fuel to make power. If you can increase these three things in the correct proportions, you can make more power. Cam, heads, intake, ignition, and carburetor are generally what needs to be improved to get more power. Unfortunately, doing this right is going to cost more than $1000.
A good running stock 390 should make 375-425ft*lbs at peak. That is a pretty decent amount of umph for a stock car. The problem is some of these were camed for low end power and some for higher end power. Low end power on a relatively light car like a 67 is going to be less than desirable.
Any ideas what cam and heads you have? That may limit the range of possibilities for what you need to do to achieve your goal. A simple cam upgrade may get you started in the right direction.
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"Yeah, were runnin a little bit hot tonight. I can barely see the road from the heat comin' off of it." Van Halen
Does it run now? It should have a 4v intake on it already. If its running right now I would go with a mild cam and a set of headers. Keep the stock manifolds if you have them, they arent easy to find. A grunt engine will work in a light car, you just dont need a deep gear. If it makes all of its power under 4500 rpm, then use a 3.00 gear and it will work pretty darn well.
cam specs would depend on what you have now and the shape the engine is in. If you need to rebuild it, you are looking at around $2k-$3k for a basic rebuild with a cam and intake upgrade.
I have a 69 with a 390 and to get you an answer, we need more info about your motor. Is the motor a bone stock 390 with factory carb and manifold, etc or does it have mods. If it has mods, which ones? Are you after top end speed or low end torque? Need a bit more info to make good suggestions for you.
As a good start, I would say look at better exhaust (good headers and good dual exhaust) and make sure your fuel delivery and spark setup is up to the task. A good set of headers and dual exhaust, new carb and good electronic ignition and coil upgrade are simple add ons that would be a good start. Other than those, things get expensive really fast. IF you haven't already read it, check this out. It was very helpful for me when I was deciding what to do to my 390. http://www.carcraft.com/techarticles..._fe/index.html
I did a 68 390GT years ago, and it just didn't have the power I expected. Tried everything, so I though. Somebody suggested I have the distributor curved to stock spec, and boy did that wake it up! It was an auto trans, so all I had to do was his the gas, and it'd fry the tires.
I know its a plain 390 that does run currently. My dad has already put a 4 barrel intake on, but still has two barrel heads. It has 9.5:1 compression and probably 280 horsepower. We plan on keeping the 2-barrel heads, changing the cam, and the pistons. Something got into the pistons and circulated around and put indents on the surface of the pistons so we are replacing them for sure. My dad is a mechanic and knows alot more about the car than I do, and I know he could make it run very good, because he built a drag car back in the day from a 65 coupe w/ a 289 and boss 302 heads, and alot of other stuff. So labor isn't a problem. Just finding out some good ideas for parts. But if there is anything else you need to know I can find out from him and repost it. Thanks
Last edited by L. Winslow11; 10-28-2009 at 09:42 AM.
I know its a plain 390 that does run currently. My dad has already put a 4 barrel intake on, but still has two barrel heads. It has 9.5:1 compression and probably 280 horsepower. We plan on keeping the 2-barrel heads, changing the cam, and the pistons. Something got into the pistons and circulated around and put indents on the surface of the pistons so we are replacing them for sure. My dad is a mechanic and knows alot more about the car than I do, and I know he could make it run very good, because he built a drag car back in the day from a 65 coupe w/ a 289 and boss 302 heads, and alot of other stuff. So labor isn't a problem. Just finding out some good ideas for parts. But if there is anything else you need to know I can find out from him and repost it. Thanks
OH, it's a standard 390. When you replace the pistons, use flat-tops. That's how Ford upgraded the compression. Replace the cam with the C6OZ-6250-B hydraulic cam. This was used in the 390GT, Police Interceptor, and 428 Cobra Jet. Use Tri-Y shorties from JBA for the exhaust.
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390 fix up ideas?
