> normal, for stock , its been recommended that, a change of final drive
>gears makes a world of difference, I,ll see what the "book" sez.
>One of the guys that I work with has changed his final drive and sez it
>really helps, he's changing them again right now to a higher ratio to see
>if it makes it even better.
>
>( BTW: he's got 2 and a-half rigs, one he uses, and another he is extending
>to 29-30 ft. thats going be some rig...)
>
>
> John & Brenda Szalay
> Louisville Ky,
I really believe that the correct way to fix this problem is to uncap the
power within the 455 itself. These motors were cut WAY down on power with
the emissions standards because the companies didn't really have any
research on making clean power. Using an Edelbrock Performer intake
manifold and Edelbrock Performer camshaft we really increased both the gas
mileage and power of our GMC. This manifold uses a Holley type carb, so we
replaced the Quadrajet with a Holley 4-barrel. We pinned the secondaries
shut to gain gas mileage and still had plenty of power. With this setup,
you will need to have a raised section in the engine cover to clear the
air-cleaner, but it is well worth it. We were towing a race car trailer
that weighed about 6000 lbs along with the motorhome and never had a lack
of power with the 3.07 gears. We were actually considering changing over
to the 2.73 gears for better gas mileage!
After changing over to a two car trailer that weighs in at over 10,000
lbs, we have changed the final drive to 3.42 from Cinnabar. We have not
seen any real noticeable improvement from this change, and the gas mileage
has gotten worse. Our experience with the final drive, however, may not be
fully indicative of what to expect because we have been having engine
trouble (over 100,000 miles towing 95,000 of them). We are rebuilding the
motor this winter (should have done it last winter but decided to paint the
GMC instead).
Zachary Zehnacker
Seemann Bros. Racing
>gears makes a world of difference, I,ll see what the "book" sez.
>One of the guys that I work with has changed his final drive and sez it
>really helps, he's changing them again right now to a higher ratio to see
>if it makes it even better.
>
>( BTW: he's got 2 and a-half rigs, one he uses, and another he is extending
>to 29-30 ft. thats going be some rig...)
>
>
> John & Brenda Szalay
> Louisville Ky,
I really believe that the correct way to fix this problem is to uncap the
power within the 455 itself. These motors were cut WAY down on power with
the emissions standards because the companies didn't really have any
research on making clean power. Using an Edelbrock Performer intake
manifold and Edelbrock Performer camshaft we really increased both the gas
mileage and power of our GMC. This manifold uses a Holley type carb, so we
replaced the Quadrajet with a Holley 4-barrel. We pinned the secondaries
shut to gain gas mileage and still had plenty of power. With this setup,
you will need to have a raised section in the engine cover to clear the
air-cleaner, but it is well worth it. We were towing a race car trailer
that weighed about 6000 lbs along with the motorhome and never had a lack
of power with the 3.07 gears. We were actually considering changing over
to the 2.73 gears for better gas mileage!
After changing over to a two car trailer that weighs in at over 10,000
lbs, we have changed the final drive to 3.42 from Cinnabar. We have not
seen any real noticeable improvement from this change, and the gas mileage
has gotten worse. Our experience with the final drive, however, may not be
fully indicative of what to expect because we have been having engine
trouble (over 100,000 miles towing 95,000 of them). We are rebuilding the
motor this winter (should have done it last winter but decided to paint the
GMC instead).
Zachary Zehnacker
Seemann Bros. Racing
