Kurt Crosbie

I've got a 355ci pushing out 400rwhp.

My question....

What size gear would be most beneficial for my application? 3.42, 3.73, 4.10, 4.56?

cmking26

Wow 400 rwhp thats awesome. As far as gears that depends on how you drive it. If you like to cruise I would go with 3.73 if not then go with 4.10 or higher. Im not sure about 4.56 I dont know anyone with them. If you search theres formulas out there to estimate rpm at a given speed in a given gear.

1racerdude

4.10's

TransAmGT94

4.10 is also my answer

TransAmGT94

Im also in the process of building a 355 would you mind sending me a list of the parts you used and a guess on how much $$$ it cost so i know how much more ive got to spend

Kurt Crosbie

You know I can't let out that kind of info...

mebanditws6

Good luck making 400rwhp with the CC305 cam unless you get some aftermarket heads like AFR's that flow around 300 on the intake side. Why not get a GM 847 with that forged rotating assembly? Seems like a waste to me.

Jason

GreenDemon

People always want to go overboard on their cams so they can push out that last bit of power on top, but in reality, for a daily driver/Sunday cruiser it would be nicer to have a strong overall powerband. I wouldn't mind a cc305 w/ some nice aftermarket heads.

Kurt Crosbie

I have stock heads. They're just ported. And as for the cam...

My engine builder said the purpose of using the cc305 was to make the engine "streetable".

383Z4ME

There are calculators to figure this stuff.

https://www.camaroz28.com/calcs/index.shtml

has lots of useful calcs.

I figured 4.10 was a little tall and would force me to a 28" tire.

kostya_f

Depends on what you are looking for. On 275 street tires 4.10 will be too much. On et streets they will be ok.

Capn Pete

It depends on where your engine's red-line is going to be. For a relatively stock car (~6000 rpm red-line) running 26" tires, 4.10's are the perfect ratio IMO.....you end up crossing the line between 5500 - 6000 rpm (running over 100 mph, but not much more than ~110 - 112 mph).

If you're making ~400 rwhp, then you'll be doing more than ~110 mph, but chances are your engine's red-line would be higher (probably ~6500 rpm at least? ) which allows more speed in top gear (upwards of ~120 mph). Any faster, and yeah, you'd need 28" tires, or a higher gear ratio.

Try out this calculator.