A Corrosion from electrolysis can be a real issue on engines with dissimilar metals. Most current antifreeze, the stuff misleadingly called "coolant," have very good additive packages to control corrosion. If you were to run straight water, the electrolysis would have a field day, eating your aluminum components at will. Either by running antifreeze or using a cooling enhancer like Red Line's Water Wetter, you can get the corrosion resistance you're looking for. Up in South Dakota you probably need the protection of antifreeze, but your cooling system would be most efficient with straight water and Water Wetter. Use as little antifreeze as you can with a mixture of water and Water Wetter.
In my race car I've run a mixture of straight water and Water Wetter for more than 10 years without any corrosion problems. It's an iron block-and-heads big-block with aluminum manifold, water neck, water pump, and radiator. I've probably changed the water and Water Wetter five times over the 10 years, and each time I tear it down, not one bit of corrosion.
Give Me A LiftQI am building a 389 for a '73 Nova with 0.060-inch-over Speed Pro pistons that will have 10.2:1 compression with 64cc chamber heads. I have some stock Vortec heads, I bought some Comp Cams Magnum roller-tip 1.6:1 rockers, and I would like to use roller lifters, but I don't know what size pushrods I should use. I was looking for a cam, but I can't find one that is less than 0.475 inch of max lift that will make my engine make about 500 hp. I can't decide over an Edelbrock Air Gap and a Victor-series manifold. Should I buy a single- or double-pumper 625-cfm Road Demon Jr.? Thanks.Roberto GarciaVia e-mail
A You've got quite a project going on here. I think you may have misunderstood what we have said in the past about the Vortec heads. Yes, a stock Vortec head should be limited to 0.475 inch max lift because of the stock valvesprings and seal-to-retainer clearance. You may step up the lift range by machining the cylinder heads to accept more lift by lowering the valve-guide boss and going to larger valvesprings. I'm sure that you've had a very tough time finding a camshaft that has such a low lift and can reach the power level you're shooting for. You could swap out to the new Comp Cams Beehive spring, which will drop into your stock heads, but you will still need to machine for guide-to-retainer clearance. Check with Comp for more info on its Beehive springs.
The stock 51/416-inch-diameter pushrods will work fine in your application. You'll want to upgrade to an aftermarket performance pushrod like the Comp Cams Magnum. They are made from 0.080-inch-wall heat-treated chrome-moly steel tubing. They are a one-piece design and will stand up well to your needs. Check out Comp PN 7372-16 for stock-length 51/416-inch pushrods. As for running your 1.6:1 pushrods, make sure when you're machining your Vortec heads for additional lift that you clearance the heads for pushrod clearance. When you run a 1.6:1 ratio rocker, it moves the pushrod closer to the rocker stud. If you don't clearance the head, the pushrod will rub the head casting.
Your 500hp bogey may be tough to reach with your stock Vortecs. You may want to have them ported to get additional airflow out of them. If not, you're going to need quite a large camshaft to reach 500 ponies. After you work out the lift requirements for your heads, look around for a camshaft. You didn't say if you were looking to go hydraulic or mechanical roller. It makes a huge difference in camshaft selection.
As for a manifold and carburetor, you'll have a much more streetable engine with the RPM Air Gap. Also, the 625-cfm carb isn't going to cut the rpm range you'll need to reach 500 hp. You'll need at least 750 cfm. We wouldn't go any larger for the street-unless the street driving is back and forth to the dragstrip.
Hope this has answered many of your questions.