Mopar Action On-line – Tech Questions


Tech Question

Andrew Yeo, West Lafayette, IN, 1970 Dodge Challenger 318

Rick, I’m working on a 1970 Challenger “Western Special”
that will be set up for handling and need to choose an engine. I like bigblock power and torque but I’m concerned about balance and handling. Can Iset the car up to get good handling with a “light” big block (451, aluminumheads, aluminum radiator, battery in trunk) or do I need to drop back to asmall block? The chassis has been stiffened (frame connectors & torqueboxes by Auto Rust Technicians) and I expect to replace torsion bars andsway bars with stiffer pieces. Your advice would be very much appreciated.

Amdrew, the short answer is : “yes”. But, like many things in life, thisreally isn’t a “yes/no” question, but a matter of degrees.

For handling, braking, accelleration, and even fuel economy and drivetraindurability — virtually every performance parameter save terminalvelocity — mass is your enemy. Less mass means you need “less” brakes -which are lighter – reducing mass! Etcetera. For handling, removing,especially, mass at the ends of the car is very rewarding — that ol’ “polarmoment of inertia” thing at work.

No question, you can remove mass from a big-block car. Beyond theengine-related things you’ve mentioned, there’s fiberglass body panels,polycarbonate “glass”, etc. With some effort and attention to detail, youcould probably get a streetable big-block E-body down to 3200 pounds or so.But, you could also reduce that number by easily another 100+ pounds – allfrom the nose – by going small block. And, with a 408-inch smallblock and,say, Indy’s aluminum W-2 style heads, you could easily make 500+ HP.

So, like so many of these personal-decision type questions, all I can do islay out the facts as I see them — once you have all of ’em, the finalchoice is yours.



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