.903 Graziano Drop gear set order

Joel K

Supporter
Just an FYI out to the community. I’ve been discussing the different options for gearing on the Graziano with John B. For my needs I am going with a .903 drop gear set which is a custom order. So, if anyone is interested in that specific ratio please reach out to him since the order is going in soon
 
Ken - I think John May have a set already on the shelf. I’d contact him directly and he can give you exact pricing and whether a set is available.

I’ll say this - I wish I had done the drop gear mod BEFORE I finished my car. The hassle of changing it out now is serious. At my next major service/clutch replacement I’ll be installing my gears. The current gearing is livable but I think it would be a more comfortable street car with a set of drop gears.

As an FYI my LS376/525 doesn’t really like being below 2krpm for very long, I definitely wouldn’t want to cruise at that engine speed. Factor in what your typical highway speeds are and be sure you’re north of 2k if you have this motor.
 

Ken Roberts

Supporter
Did you buy a set yet Cam for later install. What is your recommendation? 1.04 or these .903

My engine for this transaxle is a 720hp LS9 build.
 
I have the 1.04; I think for my car with the 525hp motor I wouldn’t want to go much more than this. With the current gearing I’ll say this - I wouldn’t want more hp, but I wouldn’t want less either. The gear change is going to make the car feel a bit slower so I’m a bit bummed I’ll be losing out on some of that torque so I don’t want to go too far. Cruising speed with 1.04 is going to put me at about 2500rpm, very livable.

The issue with this trans is all 6 gears are so tightly spaced. There’s no overdrive gear. So while I would like to have a better ratio for highway, I definitely don’t want to sacrifice gears 1-5 just so 6 works better. I think the 1.04 is the right compromise for me.

With more hp it might nudge you closer to the .903 but I suspect your car will be heavier which points to the 1.04. Safest bet would be to go with the 1.04 - highway speeds in Canada are lower and your engine speed at 110-120 kph will be very livable with the 1.04. If you’re going faster than 120kph then you won’t care how loud things are anyway ;)

Maybe ping Granville for his thoughts. I think he’s about 750hp, has a heavy stereo, and has the 1.04 gear ratio in his Graz.

My main desire to re-gear isn’t necessarily for fuel economy or because the engine is being stressed at 3300rpm - it’s the noise. Engine and exhaust noise at 3300rpm are a bit much for a multi-hour drive. Then again my drive up to LA a few weeks ago went just fine while I was wearing noise canceling headphones ;).

Fuel efficiency was about 15mpg with the occasional high speed squirt and AC running. Cruising speed was about 80mph otherwise.

Edit - I forgot, this is going into the GTR. I don’t know what the weights are on those.
 

Dan Carter

Supporter
I have the .903 gears. I only have 51 miles so still getting comfortable with the car. I have the LS3/480. Like the 525 the 480 gets a bit choppy below 2k. I have only driven city driving so far, but the .903 does keep the car quieter by holding RPM down. Honestly I don’t like the GM hot cam. Over the summer there is a good chance it’s coming out. I want street manners with a little attitude. So the .903 will be perfect for my application, a non race car that’s easy to drive light to light or while cruising. The .903 does require very slight shaving of one corner in the Graz but has zero impact to structural integrity. If you compare the .903 to the 1.04 there really isn’t a whole lot of RPM difference. I would think the best price for purchase and install might be the tie breaker.........
 

Ken Roberts

Supporter
The highway cruise speeds seem to be much lower here in my area. 65 to 70 mph at the most. I'm trying to decide which gears to use with my LS9 build (720hp). It will still have good driveability at 2000rpm. We just don't have 75 to 80mph cruising here.

Those GM hotcams and ASA cams were developed in the 90s for the First gen LT1's. Less than stellar design for the LS3 heads. There are a few good choices for LS3 engines on Corvetteforum or do as I did and have one custom spec'd for your combination. The ASA cam makes power in the higher revs due to it being designed for road racing use. It has poor lower rpm performance (less than ideal for drop gears). Ideally the cam should be spec'd with a good broad curve and higher low rpm torque to compliment the drop gear upgrade. They will be much easier to tune as well with little to no bucking at 1800 to 2000rpm.

Search on the C6 tech section on corvetteforum for the "spinmonster" cam. Highly recommended. You get about 490hp with fantastic street manners all with only a cam change. Also the Katech LS3 torquer is a great cam in my opinion.

Get your cam spec'd from this gentleman (PatG). He is famous on the LS forums. It costs $25. He has exotic modeling programs and thousands of dyno pull files under his belt. Even for the entertainment factor. See how far off your current cam is from what he chooses for you. I had mine spec'd by him. Then Comp Cams ground it (bought on Summit Racing). https://www.guerragroup.com/camshaft-help
 
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