Had Gromm Racing do some work on my LS3 and couldn't be happier with how it turned out. We went with a set of his ported heads and ended up exceeding our horsepower goal. The work was done right and the turnaround time was great, which is a huge plus. Really happy with the results and would definitely recommend Gromm Racing to anyone looking to get more out of their setup. read more

I'd give 0 stars if that was an option It pains me to speak negatively in this setting as we have never shed any light in belief it comes back around. However we have publicly supported this company, and sent many others in their direction therefore I feel it is my responsibility to caution others to be extremely careful when choosing who to trust with your business. We've had repeated issues with engines from Gromm Racing, with four consecutive failures occurring in less than five hours of runtime each. Despite thorough investigations, including sending oil samples for analysis (which returned clear results), we've been met with deflection and accusations. Gromm Racing claimed the oil analysis company was lying to protect their product's reputation. Our data logs confirmed that the engine operated within proper parameters, yet the failures--in some cases attributable to wear or fatigue--remain unexplained. Gromm Racing's primary excuses for these failures are that they were caused by driving on the limiter and a lack of oiling--claims that our data logs directly contradict. The logs show the engine was within proper parameters and had sufficient oiling. Upon further inspection, it was found that the main bearings were clearanced too tight, resulting in excessive crank damage, while the rod bearings showed no signs of heat or wear. Additionally, an oil sample revealed high volumes of aluminum, indicating significant piston wear, which was also evident upon inspection of the cylinder walls. To make matters worse, we've had countless issues with Gromm Racing losing hardware, engine drive accessories, and even valve train components. On one occasion, valve train parts had to be pulled off an employee's personal car just to complete our engine. Spare parts he deemed "not reusable" would be boxed up and taken to a storage room where we would have to request for them back. Additionally, a nitrous plate that was shipped with an intake was never found or returned, adding yet another layer of frustration to an already disappointing experience. Gromm Racing's lack of support and transparency further compounds these problems. They refuse to provide part numbers, engine clearances, or even replacement parts, claiming these are "trade secrets." Instead, we're told to "figure it out ourselves." Two years ago, we ordered billet main caps for an LSX block, paid for them, and never received them. The claim "I never billed you for a dyno session" was what we were met with when inquiring about them, however we were never invoiced and the main caps are still needed. The $4,500 block sat at their shop improperly stored and was allowed to rust, despite my repeated inquiries. Upon arrival to pick it up, I was told, "I would've cleaned it if I knew you were coming." Additionally, the blower engine was taken to Gromm Racing for a teardown, inspection, reassembly, dyno tuning, and return over two years ago. Despite countless missed deadlines, we still don't have the engine (it is now ready but not complete nor correct in terms of the injection lay out that was improperly redone nor the intake issue addressed). This repeated failure to meet commitments, coupled with an inflated ego and lack of accountability, is unacceptable. read more

Too busy rarely answer the phone in person. Turn around too long Never done on time as promised read more

Oh my 3rd project with them and every time they've overproduced from my expectations. I tend to overbuild for the type of HP I put to the pavement for reliability and this has been the place. Have a 4th and 5th in line for a reason. Motor guys are unique individuals so don't inquire if you get in your feelings. They are straight to the point and are here to talk HP, not your psychiatrist. Can't wait to install this next pig, along with the 2 after. If you want go fast that can take the abuse, I've had no failures this far and one of my builds is 5 years old and twin turbo. read more

I went to Grom to get some engine work done, heads/intake/cam swap. Everything came out amazing! Super honest, and super professional there. Very high attention to customer satisfaction, Semir is the man! I highly recommend anybody looking for engine work/performance go to them! read more

Gromm Racing - Gen3 5.7Hemi w/a few bolt on's! - Auto Parts & Supplies Near Me - San Jose, California

Worst experience I've ever had from start to finish. Took an engine there that was vibrating and Semir diagnosed it as unbalanced and quoted me for a rebuild. Said it would be internally balanced, and then later found out he externally balanced it without consulting me or even telling me. After a total of 10 months and telling me it would be done in 2 weeks for 6 months of that he finally "finished" my 347 and it was put back in the car. Many bolts and the distributor were loose and upon first start up the cam gear snapped and so it was sent back to him to fix. Once it was finally fired up it seemed like it was misfiring and the valve train was very chattery so it was sent back to him again. He gave me a whole line of bullshit about how it was my electrical system and he went back and readjusted the rocker arms. Got it back, still had loud valve train noise and felt like it was vibrating. He then said it could possibly be a clutch that was out of balance, but that was very very rare. So put in a new clutch and in got a little better, but still seemed like it was misfiring. Got a new efi harness, injectors, and maf going off the assumption he had properly adjusted the rocker arms, but still misfiring. Had a tuner look at it a the passenger side bank was significantly leaner than driver side so I had the intake taken off and valve cover and what'd ya know there were metal shavings all over cylinder two rocker arm and valve which the intake manifold is over. On top of all that I found a metal chunk in the oil pan during the first oil change and was told to run 20w-50 by Semir instead of the 10w-30 he recommended to fix a low oil pressure problem that appeared after less than 100 miles of driving. He then basically tried to blame me because the clutch wasn't balanced and said that somehow could've caused the metal chunk in the engine because it was so bad and to kick rocks. Did a clutch also cause the rocker arm to not be adjusted properly from the first start? C'mon. At the end of the day Semir is so cocky that when it was sent back twice he wanted to blame everyone, but himself instead of spending the hour it takes to remove the upper intake and adjust the rocker arms. Now I'm left with a motor full of metal shavings I can't run, he won't return an email and won't answer his phone. I've even offered to pay the labor to remove the motor so he can fix the problems, and he's too full of himself to even respond. I'm sure a ton of people have had good experiences, but he completely screwed me and now I'm out thousands of dollars with a motor and car I can't even enjoy. This is the problem with shops that promote themselves on social media because they can block and delete all the negative posts and comments, but the truth is if he's not even willing to own up to his mistakes and simply fix the engine he built for me it could happen to any one else and there are no repercussions for him. read more

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Update - about 10 years into this build with many track events. Engine is running great. These folks did an awesome job! read more

Gromm Racing - Auto Parts & Supplies Near Me - San Jose, California

I went to Gromm to get a vortec head that I pick off the chevy Tahoe. I brought to Gromm to get it deck and check. But I decided to change my route because it will cost too much money for me to upgrade my Chevy 350 tbi to a vortec head. The cost is the tbi manifold which only GM makes and they cost. I called Gromm three days later to see if I can cancel my order and they were very nice about it. I would recommend people here because they are honest which is hard to come by these days. I would total come back if I need any machine done to my engine head or etc. read more

Semir and crew went above and beyond for my cars performance . The precision machining and tuning service provided by Semir ,Dave and Gabe led too successful start to Finnish hp tq and drivability. I can appreciate the time and knowledge Theses individuals put forth to excellence. Semirs recommendations proved to be The right ones. Thanks to the Gromm Racing crew for your dedication to keeping the performance alive . I highly recommend this business. read more

Gromm is where its going on!!!! An actual gear head! Knows his shit both old school and new school Semir is the last of the machinists in town with integrity. Let him build your beast from mild to wild and ill bet you smile so hard your back teeth fall out. read more

I purchased a truck that had paperwork from Gromm Racing in it showing they built the motor. 30k miles and 17 years after they built the engine it still runs great and sounds even better. I called for an oil recommendation and the man I talked to gave me more time and information than he realistically needed too. Not only was he a wealth of knowledge but he was very friendly and willing to share it. Excellent customer service and it's very obvious they know what they're doing. I need to have them build me an engine soon. read more

This is the place to go for your machine shop needs. Bob is a very nice and knowledgable guy. He will take the time to explain the good and bads of all your machining needs. A bit expensive but definitely worth the piece of mind to know your getting a professional job. I've personally taken 3 motors to him and recommend him to all my friends. read more

Bob Gromm is great! Helped me with flow measurements on pseudo-AFR SBC Heads, and then did balancing on my crankshaft. All work was excellent. Always on-time. Always polite. Always professional. Not cheap. You get what you pay for. In this case you really DO get what you pay for. If you want the very best . . . read more

i was looking for a machine shop to do some cylinder head work on my 20V and called up gromm. explained what i needed done, told them i needed a valve job and assembly. he asked what kind of vehicle, i told him it was an audi turbo head, he said "no! i don't work on those, i only do high performance american cars!" and hung up on me. very unprofessional and disrespectful. my car is high performance and i am building the motor to handle a rather large turbo setup, but apparently if you don't own an american muscle car, this guy wont bother to do any work on it. called around and every other machine shop i called was happy to do the work for me. read more

Bob has a wealth of knowledge in heads and engines. He tries to stay up on the current trends and separate truth from fiction or rumor. His attention to detail on head, block and component prep is excellent. The only downside of his operation is the timeline. Unfortunately expect 2-3x what he quotes. If you stay on top of him it gets done a little quicker. read more

I guess I should have written this years ago. Bob's knowledge and helpfulness in building an engine is five stars. My BBC has been running strong for many years. I push it hard, running it in a competition 4x4 pull truck. Bob and I have tweaked it a few times over the years, adding some parts to improve performance. This place isn't a hack shop or cheap, so do not go in thinking your going to get great motors cheap. read more

Worst experience I've ever had. Gave them a reverse rotation sbc short block to rebuild for my boat. Installed it in my boat to find out they put a bigblock oil pump drive in the sbc. Had to take it out again to replace. Tried to fire and found out they put a standard rotation cam in a reverse rotation engine. Had to take out again. These guys don't have a clue. read more

I have Know Bob Gromm for well over 40 Years , He is a Good as it gets . If You want a Top Quality Job He is Your man . Bob is Very Knowledgeable and keeps up with all the latest Technology. You get what You Pay for and a lot more . read more