Rear End Gear ratio
 

I'm assembling all the "big" pieces to start on my 70 Camaro Pro touring project. DSE front sub and rear quadra-link suspension, 9" Moser rear housing, 4l80e trans, LSA (est 650-700hp). My rear tire height will probably come in around 27". I plan on mostly street use, but may take to an auto cross event now and again. I believe the newer Camaros run a 3:23 gear?? Any input on what gear I might want to run with this power train set-up?? I'm ready to order the center-section/gears for the rear end and can't decide on gear ratio...... I will have trans "beefed-up" but will probably run the stock gear ratios within the trans.

My thinking is maybe a 3:42 but only because that tends to be a good all around gear.

But I'd suggest you get your trans gear ratio's 1 thru 4 and find a online gear calculator (I've used American Powertrain) and plug in tire height and different rear gear ratio's to see what your rpm's are at different speeds. I'd think you probably most concerned about your highway cruising rpm vs speed.

This is what I do when considering gear changes.

Mike

Newer Camaros have a 4.xx first gear, a low 3.xx gear ratio, and a 28" tall tire.

The 4L80 has a 2.48? first gear.

So personally i'd go with a 3.89 or 4.10 with a 27" tall tire.

I was going to recommend a 3.89 ratio

My preferred rule of thumb is that I want to be around 2100-2300rpm while cruising down the highway. I tend to drive between 70-75mph. I go with the gear ratio that allows me to to that. Do your math accordingly.

Andrew