Cancel

    Open app

    Search

    JGM Performance Engineering

    4.2 (24 reviews)
    Closed 8:00 am - 5:00 pm

    Services - JGM Performance Engineering

    Auto customization

    Engine customization

    JGM Performance Engineering Photos

    You might also consider

    Recommended Reviews - JGM Performance Engineering

    Your trust is our priority, so businesses can't pay to alter or remove their reviews. Learn more about reviews.
    Yelp app icon
    Browse more easily on the app
    Review Feed Illustration

    Reviews With Photos

    327 CI Built by Ryan at JGM

    This is a true, custom engine building performance shop. If you are looking for extraordinary performance enhanced engine experience... Look no further. Ryan is meticulous with his attention to detail with respect to machine work down to expertly engine assembly. Ryan and his staff have built and dyno tested two engines for me. My first engine was a 327 CI Chevrolet which produced over 450, reliable, HP! No full engine build leaves his performance center without being fully blue printed. He highly recommends for all engine builds to be dyno tested which is done in house! On my second engine build, 327 CI punched to a 331 CI, made over 600 HP. However, when initially dyno'd, it made roughly 575 HP. This is where Ryan and his staff really shine! They take the time to expertly tune the motor and find "extra" horsepower and torque due to their years of experience with engine tuning! Don't ever settle for a crate motor. JGM will build a custom engine to your specific needs and have the experience to gain you the maximum horsepower for your hard earned dollar!

    Brandon B.

    Ok building my BBF for my boat as we speak, Ryan the Manager of JGM is awesome, I'm a pain in the ass customer and even though he is beyond busy he still has time for my questions and thoughts. Motor is not done yet but they get 5 star for putting up with me lol. I will update after the motor is done. Thanks JGM / Ryan!! Update!!!! Motor dyno I was expecting 500-600hp and about the same torque. It made 671hp and 700lbs of torque This motor is going to be fun!!!! I can't thank JGM enough

    Engine dyno

    Took our BBC 454 jet boat engine in to be completely rebuilt. Ryan and his team did an amazing job with a constant line of communication with any questions we had. Always felt encouraged to ask any questions. We also had the engine dyno'd at the shop as well. Everything was done in house, great customer service, and definitely will be back. Would recommend to anyone and everyone.

    S W.

    These guys are the best. Not only is Jim Grubbs a great honest guy but probably one of the most knowledgeable in the business. Their customer service is top notch. They have been doing great work on my 61 corvette engine and I wouldn't trust anyone else.

    351W by JGM
    Jeff K.

    I was driving my 68 Mustang today with a 351 Windsor that was built by Jim Grubbs and had to come home and post on here for the first time in my life because it is so deserving. I have been beating on this motor and listening to it scream to 6700 rpm since 2002. Still runs like a champ and I couldn't be any happier listening to my engine rev over and over and over and over. Thank you Jim for making my car the fun of my life since 2002. I will stop by and rev it for you to enjoy as well.

    Robert G.

    Great shop and great engine builders. I had a badly damaged pushrod and rocker arm. These guys helped me out above and beyond. Thanks guys for everything. I'll will be returning soon...

    A perfect 5-star rating for the guys at Jim Grubbs Motorsports! Terrific Family operation, super knowledgeable, honest and the highest level of integrity! Ryan and his crew did an amazing job building the engine for my 1970 Mach 1 Mustang, I loved the fact that my engine never left their shop. Every bit of block preparation, machining, blueprinting, assembly and the final dyno test was done at JGM. Ryan encouraged me to stop by the shop anytime and would even call me when good opportunities were present to take pictures to help me document my car build. "Old School Customer Service" at its best. When the engine was complete, I delivered it to Ventura, CA where my Mustang is being built. The car builder noticed that the dipstick that was originally in the engine was not the correct OEM dipstick that was supplied by the factory when the car was built. I contacted Ryan to schedule a time for me to bring the engine back to him to change out the dipstick tube in the block. Instead, Ryan volunteered to have one of his guys drive out to Ventura and change out the dipstick tube so I would not have to bring the engine back to him and then take it back to Ventura again. This speaks volumes for how they treat their customers... very rare to find this level of customer service and I cannot thank them enough. Do yourself a favor and trust these guys with your build, you will not regret it.

    My Ford 501 V8 Stroker motor Jim built for my '96 Ford F-350

    See all

    2 months ago

    Helpful 0
    Thanks 0
    Love this 0
    Oh no 0

    7 months ago

    Helpful 0
    Thanks 0
    Love this 0
    Oh no 0

    11 months ago

    Helpful 0
    Thanks 1
    Love this 0
    Oh no 0

    7 months ago

    Helpful 0
    Thanks 0
    Love this 0
    Oh no 0

    9 months ago

    Helpful 1
    Thanks 1
    Love this 0
    Oh no 0

    2 years ago

    Helpful 0
    Thanks 1
    Love this 0
    Oh no 0

    2 years ago

    Helpful 0
    Thanks 0
    Love this 0
    Oh no 0

    2 years ago

    Helpful 0
    Thanks 1
    Love this 1
    Oh no 0

    2 years ago

    Helpful 0
    Thanks 0
    Love this 0
    Oh no 0

    8 years ago

    Helpful 0
    Thanks 0
    Love this 0
    Oh no 0

    5 years ago

    Helpful 0
    Thanks 0
    Love this 0
    Oh no 0

    6 years ago

    Helpful 0
    Thanks 0
    Love this 0
    Oh no 0
    Photo of S W.
    28
    112
    9

    9 years ago

    Helpful 0
    Thanks 0
    Love this 1
    Oh no 0

    11 years ago

    Helpful 1
    Thanks 0
    Love this 1
    Oh no 0

    11 years ago

    Helpful 0
    Thanks 0
    Love this 1
    Oh no 0

    7 years ago

    Helpful 2
    Thanks 0
    Love this 0
    Oh no 0

    7 years ago

    Helpful 0
    Thanks 0
    Love this 0
    Oh no 0

    9 years ago

    Helpful 0
    Thanks 0
    Love this 0
    Oh no 0

    6 years ago

    Helpful 0
    Thanks 0
    Love this 0
    Oh no 0

    10 years ago

    Helpful 0
    Thanks 0
    Love this 0
    Oh no 0

    6 years ago

    Helpful 0
    Thanks 0
    Love this 0
    Oh no 0

    12 years ago

    Helpful 0
    Thanks 0
    Love this 0
    Oh no 0
    Photo of G H.
    0
    7
    15

    11 years ago

    Helpful 0
    Thanks 0
    Love this 0
    Oh no 0
    Photo of Gary M.
    0
    132
    1

    10 years ago

    Helpful 1
    Thanks 0
    Love this 0
    Oh no 0

    Ask the Community - JGM Performance Engineering

    Review Highlights - JGM Performance Engineering

    Ryan is meticulous with his attention to detail with respect to machine work down to expertly engine assembly.

    Mentioned in 12 reviews

    Read more highlights

    You might also consider

    Verify this business for free

    People searched for Auto Customization 528 times last month within 15 miles of this business.

    Verify this business

    Xtreme Autosports

    Xtreme Autosports

    (348 reviews)

    I highly recommend coming here. I called to have 2 front windows tinted and they got me in the…read moresame day. Quick turnaround around and was done when processed. Worth the money. Thanks Tony for such great service and work!

    Do not go here. I say this as someone who used to be a loyal client for NINE years and who has…read morespent tens of thousands of dollars at this shop. This used to be a good place. Not anymore. If you look through my review history, you'll see that I originally gave Xtreme AutoSports 5 stars back on October 18, 2016. Even in that very first review, I noted that the work was not done correctly the first time and had to be brought back to be fixed. That has always been the pattern here: jobs rarely done right the first time, and customers expected to keep coming back until it's "acceptable." About four years ago, the issues started getting significantly worse. I initially gave them grace because of COVID and the stress everyone was under. That was a mistake. Almost every time one of my cars went in, it came out with new problems. One of my cars was rare, and every issue was met with excuses about how "difficult" it was to work on. I eventually took it to a specialist, who immediately identified that the engine mounts had been installed incorrectly by Sam, which explained the shaking. Instead of fixing his own mistake, Sam tried to sell me a new timing chain. That's when I stopped trusting him and took that car elsewhere until we sold it. Then the same pattern started with our other cars--high-end vehicles, but nothing exotic. The excuses continued: "Do you know how complicated your car is?" "We don't have the right tools." "Bring it back again." One especially egregious example: new brakes that would not stop squeaking. When I complained, I was told, "Well, what do you expect? You live in a dirty area." So a high-end SUV supposedly can't handle dirt? That's when I knew the excuses had turned into lies. I took the car to the dealer and two other mechanics. All confirmed the same thing: the cheapest possible brakes had been installed. One even showed me the exact model--about $140 worth of brakes. Sam had charged me $440. When confronted, he claimed the dealer and the other mechanics were all lying and just trying to make money. At that point, I moved most of our cars to another shop. Unfortunately, our two work trucks were still with Xtreme AutoSports. One had a battery that kept draining. Sam kept replacing the battery. The real issue? The alarm system Sam installed was draining it--something another mechanic figured out immediately. This was on a 2002 Chevy Tahoe, not a complicated vehicle. I also brought in our sedan for a brake warning light. What Sam didn't know was that I had already taken it to the dealer and another mechanic. Both confirmed the brakes were fine--the issue was the sensor. Sam still tried to sell me new brakes. At this point I would have pulled every vehicle, but our final car--a 1995 Chevy Blazer that was my first car and my late father's car--was still there because Sam had broken another part and I had to bring it back. During that visit, he claimed the AC dial was broken. Since it was an older car and parts were hard to find, he told me to order a replacement from eBay, which I did. After I delivered the AC controller and the vehicle to the shop, the part went missing while in Xtreme AutoSports' possession. Sam initially claimed the part was there, then claimed it wasn't, then stopped returning calls entirely. Over a period of more than a month, I called nearly every business day. Not once did Sam return a single call. Employees admitted parts are frequently lost at the shop. Despite being given a formal 14-day period to locate the part (documented in writing), it was never found. To make matters worse, I later learned that the part returned to the seller was not the one I purchased, but a broken part removed from my vehicle. Sam ultimately denied responsibility, dismissed my concerns, and refused to compensate me for the lost property. To add insult to injury, my AC was still not fixed, and I had to pay another mechanic to complete the repair properly. I filed a complaint with the Bureau of Automotive Repair. When contacted, Sam lied, claiming I had lost the part--despite his own employee admitting parts regularly go missing and despite Sam previously saying the part was in the shop. If you research this business--including the Better Business Bureau, where they are not accredited--you'll see a clear pattern: sloppy work, cheap parts, repeated excuses, and a refusal to take accountability. Sam has become someone who appears interested only in making money, even if it means screwing over long-time customers. I am no longer a client. All of our cars and all of our money are now elsewhere. Learn from my mistake. Do not go here.

    Genesis 1 Auto Concepts

    Genesis 1 Auto Concepts

    (119 reviews)

    I went to Genesis 1 Auto Concepts after another shop totally ruined the clear PPF on my Rivian R1S…read more Genesis was recommended to my by my brother-in-law who had wrapped his Porsche Taycan with them. I was fortunate enough to deal with the owner Jay who was simply amazing. He showed me how the other shop charged me for XPel PPF and installed super cheap and sticky crap. Genesis took care of my vehicle, carefully removing the old PPF and working with me to select a gorgeous Profection Diamond Blue PPF. Jay is an honest guy who definitely earned my business for life. His staff is a total reflection of him and they truly care about what they do to your car. I went from the cheapest and worst experience (hair in my PPF, no paint correction done, and total con job to the pinnacle in quality control and care that is Genesis 1 Auto Concepts. Thank you Jay!!!!!

    DONT GO HERE I spent over $5,000 on repairs and upgrades, and the experience was deeply…read morefrustrating. Despite multiple visits, they never resolved the issues I had, and I had to return multiple times without any fix. It sucks because I spoke so highly about them to everyone I knew and also recommended them to others, on top of that they even installed a grille incorrectly. A part I ordered through them took nearly a year to arrive, way beyond the promised timeframe, and they tried to charge me an extra $300 after the part arrived which was never disclosed upfront they messed up and said tariffs but that should have been disclosed upfront they're exact words was "if we take a hit you take one as well" so I'm supposed to pay for there mess up ? Additionally, communication was poor they took forever to get back to me. They performed an oil change but forgot to reset the maintenance light, which is a basic step for a professional shop. Overall, their work felt rushed and unprofessional, and I strongly advise caution if you consider going there. They will try to Up charge you for the smallest things.

    JGM Performance Engineering - autocustomization - Updated May 2026

    Loading...
    Loading...
    Loading...