Custom Build Crate Motorhome Motors (455 & 403)
We think this is the best motor for the money for your vintage Motorhome
We at the Co-op spend our days making the classic GMC Motorhome the best they can be. More than just a repair, our focus is the total renovation of this machine to a reliable, comfortable, state-of-the-art road rocket for today's use. We do not build hobby toys, if you want a coach that will take you places, be a part of your life and the enjoyment you seek, our products are what you are looking for.
And to that end, a motorhome cannot do its job for you if it can't move down the road economically, reliably and in a way that makes you feel confident in its abilities.
In the past few years the Co-op has "been to the mountain" in seeking out parameters for a reliable, strong power plant to motivate our 26 foot, 12,000 pound antique hot rods (with plumbing). We're not dragging a 4,000 pound 4 wheeled car, oh no we are bringing with us every component of that car plus everything at your house save the grass. Motors placed in a motorhome have double duty, they are under extreme load every moment your foot is on the gas pedal. One weak component will spell disaster.
So you want a race car motor --- right?
Oh no! A race car motor is designed for short runs of high RPM driving,
punishing that's for sure but we punish a motor in a different way in our
coaches. We fire our coaches up in the early hours of a cold morning, pull
out onto a hilly winding road and hammer down for 6 hours to pick up a load of
regular gas and hit the open road again. Long periods of comparably low
RPM (around 2600 RPM) high torque pulling sessions without the benefit of high
octane fuel.
This is extremely difficult for a motor to withstand and this is exactly what we
have designed our motors to do.
Trying to understand what goes into a motor that will reliably take this abuse, we have discovered the balance of performance parts, custom machine work, engine building techniques, installation processes and warranty backing needed to rely that your motorhome will have as is possible.
It takes a combination of factors, not just a race car motor, to have a power plant for a GMC. Oh sure, we want to impress people on the highway by wizzing past them pushing the speed limit but I sure don't want to be overheated sitting on the side of the road while those cars you blew off pass you back. Day in and day out, strong reliable performance is what you need and what we deliver.
We have found some performance components enhance low RPM high Torque performance and others do not. Here are some of the features that make are motors very different and custom for the GMC motorhome:
O We use double roller timing chains to offset the high friction valve train characteristics of the 455 Olds motor.
O Performance valve train components, new springs, multi-angle valve job, performance rocker arm parts all figure in to a long lasting highly reliable engine. Because of the new reformulated oils now available, we now incorporate a roller cam design to reduce valve train friction which will allow our motors to run with the ZDDP additives removed. You can no longer rely that a flat tappet lifter engine will stay together long term-- or even short term for that matter without the ZDDP additive which has recently been removed from our oil supply.
O We use high RPM Federal Mougle lower compression pistons not for a high revolution motor but for superior heat dispersion characteristics and for use with lower Octane fuels.
O The heart of any motor is its
cam shaft. The cam is to a motor what a program is to a computer, you can
have the best computer in the world but without a program loaded into it to tell
it what to do--- you have a blinking blip on the screen. Our "Kryptonite"
cam design effectively lowers the operating power band of the motor making it
more efficient in the RPM ranges we require our high torque power in and this is
a key to strong performance for our coach.
O Other critical components of the motor such as fuel system (whether it be the original carburetor or the new technology fuel injection), ignition systems, cooling components, exhaust and belt driven accessories are all renewed to a reliable state and then this performance drive motor is installed with great care to be sure it will do its job well.
O Our custom machine work includes, Kolene salt bath cleaning, Serdi 3 angle valve seat machining, Machine square decking, line bore and electronic balance of rotating components, Torque plate honing, oil hole chamfering and polishing and the attention to the details you need.
It takes all of these components (quality parts, meticulous machine work, assembly with an eye for detail, comprehensive installation and one more component that should be of the utmost importance in a drive train component such as a custom built motor-- warranty.
Your local engine builder will usually say, "bring the motor back to us if there is a problem and we will fix it". But wait, our motorhomes were not meant to stay within arms length of home, you want this puppy to take you places you have never been. So what happens when you are clear cross country and an issue with your motor comes up? You end up somewhere at "Bubbas Auto Emporium" and Scooter, Bubbas head mechanic, explains that he never saw a front wheel drive motorhome before! And he is your best shot within 500 miles of getting your coach fixed! What now my love? No, you need a nationwide warranty, one that assures your motor was put together well and is working as promised and if there is trouble, you need someone close to where you are to help out. Our Custom performance build GMC motors carry a full year parts warranty which includes a 6 month warranty on labor if the motor needs to be repaired or replaced.
Most performance motors carry little to no
warranty, they cannot. Most motors built by the performance people are
used in race application where warranties are a foreign word. There is no
guaranty on a race motor, non whatsoever. Usually people that give
warranties are production stock engine builders and they are usually loaded with
disclaimers and requirements that make it difficult to feel confident in your
purchase. We feel so strongly that our motors will perform well for you that
we guaranty our work, nationwide. Now that should give you the confidence
in our work and our motors you are looking for, thats because we care and we
feel we know what will do the job. 
Who builds our motors? Do we have Grandpa in the back room polishing cams or Bubba over at the speed shop dunking blocks in a 55 gallon vat of tune dip? Our engine program has been an evolutionary discovery, along the way we have learned what goes into a performance engine for the GMC motorhome. Also, we have spent much time and money building premium motors to select this component compliment. Today, our motors benefit from that attention to quality. We have looked for a quality engine recycler, one who has years of experience, one that will build our motors to our specifications, one who will stand with us to warrant that your Co-op performance build motor will do its job and one who can keep up with our turn around requirements. We have found such a builder through the Custom build performance division.
of
Jasper. Yes, this company has proven itself a quality member of the
automotive industry since 1942. Their production division builds thousands
of engines a year and their totally separate Performance products division has
built to specification performance application power plants in their exclusive
custom plant in Indianapolis In. for many years. They are the arm of
Jasper you may not ever have heard about, they are the ones building motors one
at a time anyway the customer specifies and warranting them through their
nationwide dealer network. This is the best of all worlds for reliable
custom built backed power plants specifically fitted for GMC motorhome
application. I am proud to be a part of this program, we have worked hard
over the years to get to this point and worked hard with Jasper to design and
build a superior product "Just for" the GMC.
Here's the good news! Pricing
"How much" is always the big question. I tell people we can do anything with "cubic dollars" so the question is not can it be done--- no, the question is how much will cost me and here I think we have some good news! You can always find "Bubba" out back under a tree that says, "Yep, sure-- did work on one ah dem fancy front wheel drive gizmoes once"! I can do the work fer ya CHEAP! And thats where you're going to take your motor? Why make a decision to take your motor anywhere, just think how much fun it will be finding a tow truck and a shop out there willing to take your money and "do what to the motor?"
Why not be pro active and get your drive train in shape before IT puts YOU in the poor house. Its a fact that a fresh motor performs better than one with wear. Its getting harder to find core blocks so if you have notoriously low oil pressure, Anything under 10 PSI is grinding away the bearings, maybe you should think about having your motor brought up to better than new condition now.
Our Custom build, Dyno Designed 455 or 403 long blocks currently run $5,500 with your good long block as a core. This new crate motor is built with our new roller cam design using our "Kryptonite cam specifications. Of course bolt an acc. like water pump, fill work on the intake, carb. etc. are additional. If you compare this price with other similar performance designed and built motors you will find this extremely competitive. Of course if you compare this to Bubbas production shade tree job, it will be more but is that the sort of motor you want to have pulling your home-- excuse me-- motorhome? Remember, this is not a stock car motor, this motor was built to our specs. using our selected components. This is not a "flat tappet lifter" motor, it is a "roller cam" motor. This custom built Jasper performance crate motor can only be purchased through the Co-op--- why? Because it is actually our spec. motor! Listen to all of the boasting of others but in the end, rely that the Co-op will provide you with the best for your application.
If you have other questions concerning our
performance Jasper Project, give me personally a call on our toll free line
1-877-275-4462.
Interested in one of our "Co-op Motors" for your coach but you do not live
nearby? We are now rolling out an "in the field" installer program for our
new motor. Go to field installation
for the details.
I would like to thank Drew Koba
for his efforts in bringing this project to market. Having his expertise
and experience has made a difference and I appreciate his efforts for the GMC
community. Drew is still working with us on parts sourcing and motor
enhancements. We all get by with a little help from our friends and
together we can make a difference.
Specs
Our Co-op Performance Build designs have been dyno tested and pedigree proven to be the motor we want it to be. Here are the dyno results you should expect from our motors. Each motor is built to these exact specifications and would dyno to the results below. Each motor is dry run to assure accurate assembly and operation and to "run in" the cam. This is the ultimate to assure you are getting what you pay for-- no excuses!
Click here Flat tappet spec for the latest engine dyno specs. from the last flat tappet lifter crate motor from the Co-op. Afterward, we will be building only roller cam motors so this information here will be most important to assure consistent performance from our Co-op crate motor program. Take a look and compare.
Fuel consumption graph
Power/ Torque graph
464..6 ft. lb. of torque at 3000 RPM is fantastic. The torque curve is very flat across the board & so is the HP! You don't see that on a production built unit!
Yes, we used a Stuska
dyno-- yes, "Dyno Dave" did the pulls himself
-- and best of all yes, we are happy!
Here are independent "chassis" dyno specs on one of our Jasper built "Co-op Motors". A 455, you should expect similar performance from out package. Not the torque output at the useable RPM range our coaches turn. This test takes into account pumps, transmission loss but of course not wind resistance.
Just completed is our engine dyno spec. on our 403 "Co-op crate Motor", take a read
And now a comparison chart of horse power & torque on our 455 and our 403
The 455 (red line) has19% more torque and HP but even at that the 403 did well. These are actual engine dyno specs. being compared. The curves are both similar showing our cam specs. work well on both motors. Take your pick, either motor will do a great job in your coach.
Want to know more about why our crate motors work for the GMC? Take a read on a pretty involved "white paper" on the GMC drive train and what you should be looking for when re-powering your coach. Go here http://www.gmcws.org/Tech/Final_Drive_Ratios.pdf for a look at some real world test results. Thanks to Chuck Botts for all of his hard work putting this information together.