They decked and completely rebuilt the heads for my 454 and they were reasonably priced. The work was super high quality and they are a great resource as far as build advice goes. I have to give Rex special thanks on this build as he has been my primary source of advice, and he has never moved me in the wrong direction. I highly recommend this place.

Greeley Automotive Machine built my 331 stoker for my 1965 Mercury Comet. I paired the engine with a T5 5 speed manual transmission and a Crites Restoration ram air fiberglass hood. I could not be happier with the work that was done by Greeley Automotive Machine.

This place is amazing if there where 10 stars I would give them all my business any day thank you all

Good shop got my project done quick and correct.

They cleaned, crack checked, bored, honed, balanced crank, rods and pistons and complete head work. I assembled this 360 then dropped into my 85 RC and it started right up. Runs like a freight train. Thank you guys.

Solid and trustworthy

I’ve known Danny for a couple years now and he’s been nothing but helpful. Had my head and block worked on before i rebuilt my engine. They had it done pretty quick and their work is good. Danny though goes out of his way to give advice and help any way possible. Only machine shop i’ll go to for as long as i live in colorado.

This place is awesome ! They got all the right stuff in all the right places ! I spent a half a day hittin checker auto , advance auto auto zone lookin fr header flanges . This place had em the whole time . Went in today tryin to find a alternator bracket . Ther it was hangin on the wall at this place ! Killer engine shop ! Thanx fr all yr help guys !

Its great. The guys there are always helpful and very friendly. They always have what you need or will bust there donkey to get it. Great place

Great group of guys. Courteous and professional. Had an emissions test done.

Bruce and the staff are easy to work with and always helpful.

Very friendly and helpful

Bruce is awesome to work with and there work is great 👍.

Awesome shop with experienced technicians.

This shop was a NIGHTMARE to deal with, they destroyed my head.I have a 1987 Mercedes diesel, and I needed to have the head pressure tested and wanted to see if it was warped. That is all I said they could do, and made sure that they understood they needed to talk to me before doing any work beyond this. The car is not worth much and I wanted to make sure it wasnt going to be too expensive to fix.I stopped by their shop and found out how expensive the work was going to be. I said “DO NOT DO ANY WORK until I talk with my father and confirm that we want to do this”. They said “OK!” (This is a super simple concept, and I told them this several times).I show up a week later to find my entire head 100% disassembled and completely broken down. Everything they could have touched, they messed with in direct defiance of my instructions. The head was in good shape (past tense, it is now scrap). I was probably going to bolt the head back into the car as is, but now it is literally in dozens of pieces and is nothing but trash. They gave me a bag of nuts/bolts and valves. I feel this shop really screwed up.

Large selection of performance parts in stock.

These guys are top notch!!

GAM is a lifeline for the area. It is hard to find a quality machine shop that treats customers fairly and honestly. Rex and Bruce always shoot straight with me and they do incredible work. If you need machine or assembly work done these are your guys.

Had 2 Subaru heads redone here, I had both heads valves done, decked and cleaned. Shop was quick and very professional.

I wont call and ask for reference on own motors any other place than machine shop these guys have done me right from the start thanks machine shop

I had GAM balance the rotating assembly for my Chevy 383 stroker and it runs so smooth its amazing! Thanks guys! Great job!

These guys are great. Bored out a head for my jet ski. Great to work with and had it done extremely quickly. Scott and Rex were a great help to me. Ill be back and I highly reccomend!

Quick emissions, friendly. Thank you!

Very good job

Place is a joke. Had my 390 rebuilt here. They bored number 3 hole .60 over for a 460 then put a sleeve in. It never ran right, would overheat and ping. They found every reason as to why it wasnt their fault. Found out later about the sleeve later from a former employee. Questioned them again and was told we wouldnt do that. Well we took the motor apart and right there in #3 hole is the sleeve. I wouldnt trust them to sweep my floor let alone rebuild anything of mine.Work order wouldve been under my fathers name. And Mr Yackey knew what he did

Always knowledgeable and have about most fittings you need in stock

Best machine shop around.dont take your stuff anywhere else!

Not an auto shop. They are a hotrod shop. But they do emission tests on deisles and they saved me a little money on my F-250 over everywhere worse I called. Also nice guys. If you got a hotrod Im sure theyll hook you up.

These guys did a great job and feel pricing was very good, thanks fellas

Speed shop has tons of parts.

Good job

Always prompt service and quality knowledge.

Great place for all your engine needs, very friendly and knowledge staff.

The best machine work and great support for our race car

Great place. Very helpful and great selection of parts.

The best in Greeley. If have a problem they will help you.

Very knowledgeable honest and the work was done in a timely manner.

Excellent work and very knowledgeable

They did good work but took forever

If you need a engine built.....go here and the whole crew will deliver !!

Had a set of aluminum heads cleaned and decked, here. Ive had about a dozen heads that I worked on so far cleaned and decked (its a pretty standard thing to do) by various machine shops around the country, and this was the shabbiest work Ive seen to date. There were small chunks hanging off of the head from the decking, and it was obvious that they didnt attempt to clean them. I had already soaked, pressure washed, and hand cleaned them rigorously prior to working on them - and they came back with the same polish, same sharpee notes Id written, etc. Even a pressure washing would have removed that much. An ultrasonic cleaning would have made them so clean that they wouldnt have looked the same, and instead they were handed to me in the same condition I left them. I was told the $50 cleaning was REQUIRED to have them decked. So I pull up in a nice car, wearing nice clothes, and apparently Ill be easy to take advantage of? Multiple times they told me your mechanic and multiple times I had to say I am my mechanic..The deck job wasnt much better. Ill say itll work, but much worse and Id be asking for the $$ to cover new heads and labor. Theres plenty of options around Colorado. Go find them, instead.

Good place for diesel emissions

I brought my 440 in for a repair and freshen up plus a run on their in-house dyno. Bruce Yackey, owner, gave me the cooks tour, discussed at length their capabilities, and made me feel welcome. I noticed they had a lot of engines and heads waiting to be worked on which is a good sign of a strong business. The work done was very good and I was given advice on pertinent upgrades which I had them do. The dyno was a challenge as a brand new lifter (Comp Cams) let go and ruined the cam, both cam and crank gears, and timing chain. Bruce took care of the damaged parts and treated me very fairly on the labor and dyno time. The engine is back in the car and running great. I would recommend Greeley Automotive to anyone with a high performance motor as long as you dont need it back in a month.

Couldnt even get anyone on the phone for an hour....

Rex knows. If you dont, Rex does

Great service, knowledgable staff

Its the only machine shop I will trust with my classic car engine head rebuild and any other engine rebuild.

Professional team

Got the Race car parts!

Amazing!

Fast

Weird they don’t do engine swaps when the name of their company has the word “engine” in it. I guess engine swapping is too difficult for them. I’d have paid them a lot too. Just weird. Very weird. You’d think they’d be willing to do anything to a car since they’re a car shop. But ok.