I've got a 383 crate engine in my '75. It put out 420 ft*lb. at 3500 rpm and 350 hp at 5000 rpm. I will be installing a Richmond 6 with first gear 3.04, along with a 3.36 rear end. I have heard from several people this combination would handle a 15 pound aluminum wheel just fine, and I've heard from as many people I wouldn't like it a bit. I understand the issue at risk is hard take-offs with a lot of clutch slipping.
One characteristic of my engine I just loved was how it would take off so easily with hardly any clutch slip. On hills you could just let the clutch out a little bit 'til the motor slowed some, take your foot off the brake, the car wouldn't budge, give it a little gas and let the clutch out the rest of the way and you wouldn't roll a bit on a hill, with next to no clutch slipping. I sure hate to give that up, BUT the motor sure takes a long time for those rpms to climb, and I'm tempted by the alum. wheel. I've never been around them, though, so I have no feel for just how much clutch slipping and start-off issues I'd have to deal with. Can anyone give me some advice?
Thanks, Patricia/'75

I failed to mention the car used to have a 26 pound steel wheel and a Borg Warner with 1st gear 2.24, along with the same rear end, 3.36. So basically I have a 15% lower first gear now with the 6-sp going in, and I am wondering how much lighter my flywheel can go to give me a little quicker revving without killing the take-off drivability.

The lighter flywheel ususally helps at higher rpm. It may or may not help at low rpm. It could even slow you down. Not common, but the lighter wheel may not have enough mass to maintain the engine speed between power pulses. This means each power stoke has to make up more lost motion, therby slowing down the acelleration rate. This may not happen to you. Other factors play very strongly. What is the weight of the crank shaft? What transmission? Power acessories? An A/C and power steering unit can be a replacement for flywheel weight. How about the clutch itself? Anything that adds to total rotation mass connected to the crankshaft is a factor. The results can also be affected by gear ratio and rear axle ratio. Once the clutch is engaged, this includes the drive shaft. Steel or alum and carbon fiber?
The lighter wheel will help your 1/4 mile times and top end. It might help low end. It might hurt low end, and cause vibration.

I know this is not a exact answer. But they are all things to consider. Talk to someone who has used a combination similar to what you are proposing, and see what results they got. Perhaps Summit Racing or Jeg's Racing may help.

Ken Styer

|UPDATED|1/21/2004 9:07:01 AM (AZT)|/UPDATED|

Hi Ken,
I see there are a ton of variables that should be considered when picking a steel vs. alum. wheel. Man, I wish there was something in-between! I had a 26 lb. steel and would sure like something a few pounds lighter, but I'm thinking alum. may be pushing it. I hate to have around-town drivability suffer too much. Oh, well. Guess I'll have to stick with steel. Thanks!
Patricia/'75