Axle ratio with 521

[cwmcobra]

I guess I'll have to check some things. I just installed a new custom carb from Pro-Systems and am in the process of tuning it. I can tell it has better top end, and haven't got the low transition tuned right yet, so will wait and see how that turns out. I think I will also make a run with no air cleaner to see how the torque feel compares. I have a 14" air cleaner with 2.5" tall K&N element, but what I did to get it to fit under the hood might be causing more restriction than I thought. Exhaust can't be a problem. 2" header pipes to the sidepipes with nothing but spiral turbo baffles, no mufflers. I'm pretty sure I didn't mismatch the parts in the engine; the only internal possibility I can think of is that the timing set was installed in a retarded position and I'm not getting the spark advance that I think I am. Guess I need to read up on how to degree the cam to check this. I know it was installed in the "standard" position, so unless the sprocket was mismarked, that shouldn't be a problem either.

Food for thought. Thanks for that!

Chuck

[greg schroeder]

I'd figure out how much wheel HP the car has, estimate trap speed in the 1/4, use tire height and rear gear to calculate and have 4th gear a couple hundred RPM lower than your shift point at the end of the 1/4 mile.

[Tony Aprile]

CWM...do your calculations first....with your tire and wheel size it looks like you'll be doing a whopping 57 mph at 2200 with 3.08's compared to the 70 your doing now with 2.75's... give or take a mph... with your 1 to 1 final drive 5th gear. I know you want more acceleration but you also have to watch your cruising rpm's on the highway.

Let the torque of the big block do it's thing and keep the gears, just my opinion of course.

The bottom line is... at what rpm's do you feel most comfortable on the highyway and at what speed do you want to maintain those rpm's...then gear accordingly.

Tony