😎 Sir, with all respect to you, there are better choices available.

 

They are junk. As mentioned there are much better choices than a GM crate engine.

 

Texas Squirrel,
Such as?
Doug

 

I think they come with a truck oil pan that likely will not fit.
That's a $400 addition or more if you need a different pump.

 

No complaints here. I bought a GM502 long block during the COVID fiasco mostly because it was readily available. Paid Summit on a Thursday, crate in my driveway the following Tuesday. Installed a 6 Quart Moroso pan and crowned it off with the wares in my sig below. Are there better engine builders? Always. Can they meet your timeline? Maybe. IMHO the GM 502 long block is a stout and reliable foundation for a 600HP build.

 

Initial problem was that they used low tension oil rings plus poor gaskets and stamped steel rocker arms. A friend of mine picked up a used one fair price and still using today no issues. He had the rings replaced with STD tension rings during a check a fresh up of used engine. Blueprint and Jones are real good choices and are for less then GM.

 

Four years next month for my Mark Jones Big Block, runs great very satisfied with my purchase, not one drop of oil on my garage floor.

 

Such as what, better choices? Take your pick, as long as it's not a GM crate engine. Members here are having great luck with Mark Jones engines for one as well as Blueprint Engines. GM is bottom of the barrel.

If I am correct the Blue Print 502 has a steel crank not a forged steel crank. that is a deal breaker for me
Doug

I think they come with a truck oil pan that likely will not fit.
That's a $400 addition or more if you need a different pump.

If you buy the Low HP 502 it is a truck motor, The 502/ 502 HP is a performance motor.
Doug

 

If I am correct the Blue Print 502 has a steel crank not a forged steel crank. that is a deal breaker for me
Doug

How many crankshafts have you seen broken?

 

No dog in this hunt but I would like to understand specific issues with the GM crate engines. Some pretty strong feelings here but really no facts so far other than low tension rings.

 

There has been many threads here over the years, specifically about the 502 and quality issues related to them. They seem to have the worst reputation. I dont think other GM crate engines have been nearly as bad. My zz383 has performed great over 10+ years.

 

One man’s junk another man’s treasure…

Long block specs below:

Site Maintenance

 

BP long block. Specs in link.

GM Big Block Compatible 502 c.i. Pro Series Engine - 627 Horsepower - Long Block

BluePrint Engines 509 c.i. big block GM style proseries crate engine - longblock. Includes 30 month / 50,000 warranty & BPE Dyno Promise. Part #: PS5091CT

blueprintengines.com

BP all 502 offerings.

GM Compatible Big Blocks - 502 c.i.

We give you more than just an engine — but engineering at its finest. And those who drive it, know it. The fanatics. The families. The thrill riders. The joy riders. And everyone in between. No matter who we serve, we share a genuine passion that unites us all on these streets, strips, or any...

blueprintengines.com

 

Suggest also looking at CNC Motorsports short blocks. If I had a do over I’d probably opt for their 509 or 532ci short block.

 

I bought a 540 short block from Shafiroff Racing over four years ago and have over 20,000 miles on it. Zero issues. They use Dart Big M blocks and forged rotating assemblies as the foundation for all of their builds and top quality name brand parts as well. They don’t just throw parts together and call it an engine. They final machine the blocks in house and blueprint the assemblies. All of the machine work is performed with Rottler equipment. You get what you pay for. I would buy from them again in a heart beat. You can roll the dice with a GM crate engine. There are success as well as horror stories about GM crate engines. IF, you got a bad one, how much more time and money would you have to throw at it to make it right on top of the original purchase price of the engine. I agree with many above, there are better options out there.

 

There are success as well as horror stories about GM crate engines. IF, you got a bad one

I believe the GM crate engines are rebuilt from outside sources, NOT GM, GM just sells ‘em

 

Quality concerns aside, it’s just a lot of money for the amount of horsepower.

The blueprint 502 for example, has 100+ more hp, for a couple thousand dollars less. And a much more robust and accessible warranty.

 

GM 502 comes in a Gen 6 block. If you want a cruiser there are several oil pans. If you are after performance and windage is a concern, you are very limited because of your crossmember and center steering link. If you chose raised port exhaust, you are definitely in for $$$$.
Personally I would build a 489 - 505 out of a mark 4 block. So many more options for everything and they came in your body. A good 489 will give you more power than you can ever use on the street at a much better price. Save your money on the 502. Build a mark 4 block , even a 468, put the extra money into adjustable suspension, double adjustable shocks and good tires and blow the doors off any stock 502.
Rick

 

Call Blueprint and see if they offer upgrades.

They do have upgraded forged steel up graded rotating assembly.
Doug

GM 502 comes in a Gen 6 block. If you want a cruiser there are several oil pans. If you are after performance and windage is a concern, you are very limited because of your crossmember and center steering link. If you chose raised port exhaust, you are definitely in for $$$$.
Personally I would build a 489 - 505 out of a mark 4 block. So many more options for everything and they came in your body. A good 489 will give you more power than you can ever use on the street at a much better price. Save your money on the 502. Build a mark 4 block , even a 468, put the extra money into adjustable suspension, double adjustable shocks and good tires and blow the doors off any stock 502.
Rick

Thanks for the information, I already have QA1 coil overs front and rear with there dual adjustable shocks and stabilizer bars front and rear, also tubular A arms.
The more I discuss an engine for my 1970 Chevelle the less I think I will do it. There are so many people all with there opinion on a motor, I remember Blue Prink engines years ago when I did a complete frame off restoration on my 1967 ELCO, I ended up with a LS1 stroker motor which put out 500 HP with a carb. That to me makes more sense than going for a BBC motor.
Doug

 

With an engine builder you should be able to select the parts you want for your engine, provided you wait for them to build it. On the other hand the ZZ502 is a take it or leave it meal deal: You take their RINGS, you take their PISTONS/COMPRESSION RATIO. You take their GASKETS. You take their OIL PAN. Etc., etc. Note that the ZZ502 engine comes with extras (Balancer, Flexplate, etc. that you may not want).

For me a big killer is the ALUMINUM HEADS on the ZZ engines are HEADERS ONLY -- Factory exhaust manifolds don't fit, and The Wife hates noisy headers with the 3-inch exhaust.

I have a 454 HO (No, I would not buy it again) and I must admit that it's been bulletproof.

If you really want the convenience of an engine in a short time, you could go with the shortblock version of the 502 and, after replacing the rings, build it up from there using your choice of parts. The CPP 502 block is pretty decent (much better than the CPP 454 block) as a basis for an engine.

 

I am not in a time crunch, My 396 runs fine it has a solid lifter cam that would not be my choice. the motor bucks severely if you let it idle down in 1st gear. I would like a Hydraulic roller cam, one with a not so aggressive grind. I am afraid that if I go into this OEM NM motor I will have to rebuild the complete motor. I am going to put the OEM motor on a rolling stand in the garage, it is worth more to leave it alone if I were to sell my Chevelle.
Doug

 

1st thing I would do with a factory GM 502 short block assy. is take it to a machine shop and have it power honed with deck plates. GM does not do that and I seem a few 502's with poor ring seal by looking at the cylinder walls after a few miles.

 

Why would you do any of that? The best thing to do is not buy a GM engine to start with.

 

I have one for sale, I'll bet it doesn't have 5,000 miles on it. It has a set of Brodix Race Rites on it and a retro hydraulic roller cam. The oil pan got a hole in it and its owner parked it. Low miles. I took it in trade for a 10.5:1 compression 750 HP 489 I had for sale.

I don't have to get much for it, come get it. I can even put a pan on it and run it on a run stand for you, I drove the car it was in before making the trade. It runs, sounds decent, maybe 500 hp. Blowout sale priced.

 

I find it difficult to accept claims that GM’s Factory Crate Motor program, which released its first 502BBC offering to the public in 1991(!), routinely produces a high percentage of grossly defective products but yet remains a going business concern. Are there occasional exceptions? Sure. And if one happens to be bitten by a gross defect would it leave a lasting negative impression? Absolutely! But these unfortunate events can and do also occur with the custom builders. I’m no special pleader for GM or its products nor any other builder for that matter. I do however believe such discussions should be measured and rational.

 

I find it difficult to accept claims that GM’s Factory Crate Motor program, which released it’s first 502BBC offering to the public in 1991(!), routinely produces a high percentage of grossly defective products but yet remains a going business concern. Are there occasional exceptions? Sure. And if one happened to be bitten by the defect would it leave a lasting negative impression. Absolutely! But these unfortunate events can and do also occur with the custom builders. I’m no special pleader for GM or its products nor any other builder for that matter. I do however believe such discussions should be measured and rational.

Fair point. In fact, I bought a 454HO new, after a "builder" botched my 396 rebuild. Then, I had to disassemble the new 454HO and plate hone/re-ring it as it was an epic oil burner. Didnt notice until warranty was way expired.

About the same time my neighbors GTO's 400 spun a rod bearing after an expensive rebuild by a very reputable shop. Again, way out of warranty as the car is rarely driven.

This is why for me, warranty (that is actually honored) is of the utmost importance.

 

So what about buying a complete LS or lt are they also bad? Or just 502's? The 502 was really only made for boats and I really never hear of problems. I had a 470hp 502 efi in a boat where it belongs and only had springs wear out.

 

Never heard the story about "The 502 was only made for boats" but that shouldn't make any difference. They would be just as bad if not worse in a boat with them having to work harder. The ones I have seen many of are the 502 and the 427. With all the better choices out there I don't know why anyone would buy a GM built engine. But hey, don't let me stop you.

 

GM does make several models of the 502 CID,. Truck, performance and marine application's.
Doug

 

A GM 604 Crate engine makes between 397 and 403HP from GM. It is used in sanctioned racing series. We have a customer that builds 40 to 45 of these a year as freshened engines. He took a new one apart, dyno'd it at 400HP. He brought the block to us and we used the honing technology of today that is on our Rottler CNC hone and put the RVK RK and RPK number that have been developed by Rottler and Total Seal along with the cross hatch angle. All of which wasn't used 40 years ago. We also decked the block on our 4 axis Rottler CNC to no more than .009" removed per rule book. He then assembled the engine with same rings and same bearings and put it on the same dyno. Gain of 23HP. That is a 6.5% increase in power with hone and decking. He then took the engine apart and blue printed the oiling system and the cylinder heads to the rule book. I am not allowed to give out the actual number but you can double the the first increase. So using the latest in technology, good equipment, and truly blueprinting a build netted a power increase over stock GM stuff of 13%. This is at a higher build cost, BUT his engines run longer between freshen ups than others so it is money well spent over the longterm.

 

That is the kind of detail you don't get with a GM crate engine. Some people are okay with sub par quality.

 

I think we’d all agree —superior workmanship, better technology and materials, more time, effort and dare I say money, often create superior results. That’s what can separate the excellent custom builders from mass factory productions. But that doesn’t necessarily relegate factory engines to the junk pile. I applaud those who buy factory blocks and “upgrade” them AND those who buy superior custom builds and forgo the “unnessary hassle.” I get it. I also get why some folks “refresh” their tired old engines in their own garages knowing good and well that the end result will be far from optimal. It’s all good gents, keep’m rolling.

 

I have 502 blowout priced with low miles. Brodix Race-Rite heads and a Comp retro hydraulic roller. I was gonna build it but I started thinking all I will use is the block, why tear apart a running low mile engine, for the block? I thought, someone can use a running big block with a hot rod rough idle. The cam has a rough hot rod idle, I drove it before taking it in on trade for a 750 HP Ripper Wrench 489.

I don't have room for it at the moment, so it's blowout priced, doesn't come with any accessories on the front of the engine or brackets, or intake. Everything off the front of the engine is going on the 489.

Come get it, Florida, I'll even pitch in on gas money to get here.

 

I wish Florida was closer!

 

I can process credit cards on the spot through Bank of America online terminal as well. Does that help to make Florida seem closer by chance?

I have a gantry crane it'll be like a drive thru window, and I'll pitch in on the gas money too!