New Gm 620 Hp Engines

[BADASS38CHEVY]

JUST RAN ACROSS THE NEW GM 620 HP ENGINES JUST CAME OUT. CHECK IT OUT. www.gmpartsdepot.com .CLICK ON PERFORMANCE ENGINES AND CHECK OT THE 620 HP AND THE 720 HP ENGINES. CLICK ON PAGE 5 AND GO TO THE BOTTOM OF PAGE FOR THE 572 INCH ENGINE AND PAGE 6 FOR THE 720 HP ENGINE .

[LVjetboy]

Nice engines. But does that 720 rated hp 572 burn dock gas?
:)
jer

[GofastRacer]

Well, at 12 to 1 comp it all depends what they have at the dock!.:D :D

[HammerDown]

$13,600 for the 720 HP Motor...not bad at all. A little to much compression for a river Boat and a change of oil pan would make a great motor....no?
I've got that amount in my change pocket for that Motor.

[Dave C]

I ran a 13:1 motor in my Daytona. There are no gas-docks out here that would fuel that.
So I would drop the mortgage payment at the gas station and haul a bed full of gas cans to the lake.
It was fun though:D

[230Stingray]

I am seriously considering the 620 hp version for my boat. I have chatted with Dennis Moore a few times about this motor. He thinks it would be a great torque monster but the cam is a little wild in it's present state and would probably cause a water reversion problem. He gave me some cam specs he felt would work well in this motor and still produce 575-600 hp and 650 ft pounds of torque and still have a smooth idle. I have run a ZZ502 in my boat for over 4 years now (ever since they came out and you had to assemble the top end yourself) with absolutly no problems. I'm still doing some research on a few things about this motor such as flywheel etc, but I think one of these will be in my future.

[HammerDown]

Why not the 720 HP one and run a thicker head gasket and or a Cam that would bleed of some compression?
With Aluminum Heads and moderate Timing I would think 10.75:1 would work just fine on 93 pump gas...no?

[230Stingray]

Originally posted by HammerDown
Why not the 720 HP one and run a thicker head gasket and or a Cam that would bleed of some compression?
With Aluminum Heads and moderate Timing I would think 10.75:1 would work just fine on 93 pump gas...no?
Interesting thought. Anyone else want to pipe in with some ideas?

[GofastRacer]

Of course it would work but you will make a big sacrifice in the power department!..You get what you pay for!..:)

[Dave C]

That 572 looks like a nice deal.
I had a 10.9:1 in a 502. but I never had the brass nuts to run pump gas.
I think 11:1 is pushing it but I heard it could be done but I did not want to be the guinea pig that tried it. Especially with the load put on by the jet.:eek:

[cyclone]

Originally posted by GofastRacer
Of course it would work but you will make a big sacrifice in the power department!..You get what you pay for!..:)
its a pretty good idea. GMPP has been underrating their engines for the last few years so dropping the CR a bit would probably have the engine making the stock claimed hp. I know my last crate motor showed 40hp over what chevy claimed right out of the crate at two different dynos. I believe Westech also dyno'd one of these motors recently and said that GMPP's numbers were way low.

[HammerDown]

I asked my local Engine builder about that GM/Race Crate 572/720 engine for $13,600. I belive he may have been offended some what. (I know him very well)
Either because he knew he couldnt build something equal for that price or he knew it was a good deal and made the comment "there cant be good parts" in that block, and ya get what you pay for.
I dont belive for one minute GM would put out junk...just look at the list of parts in that Motor.
PS. I did'nt go into his shop with the attitude why buy yours when I could buy this....just asked him what he thought about it.
Unless I'm missing something here...but that motor for that price sure seems like a good deal.

[BADASS38CHEVY]

Here are some more specs i found on this engine. the price on a long block for the 620 hp is $10.600 less carb, distributor, water pump,and intake.the price is getting better. GM’s most powerful Street engine ever produced will make your Street Rod or Muscle Car the envy of the neighborhood. The ZZ572/620 is built around an all-new Gen VI tall deck race block, filled with a forged, 4340 steel, 4.375” stroke crankshaft, shot-peened rods, and forged aluminum pistons. The newly redesigned rectangular port aluminum cylinder heads result in a pump gas friendly 9.6:1 compression ratio. Also included is a .632” lift, hydraulic roller camshaft, roller rockers, dual valve springs, single-plane intake manifold, and an 850cfm Demon carburetor. A GM HEI ignition feeds the ZZ572/620 all the electricity it needs to yield 620hp and 650 ft. lbs. of torque! ZZ572 / 620 Technical Information ·HP: 620 @ 5500 RPM ·Torque: 650 Ft. Lbs. @ 4500 RPM ·Compression Ratio: 9.6:1 ·Bore: 4.560” ·Stroke: 4.375” ·Block: Bowtie Tall Deck with One-piece rear seal ·Crankshaft: Forged 4340 Steel ·Connecting Rods: Forged 4340 Steel, H-Beam style, Shot peened ·Pistons: Forged aluminum with full floating wrist pin ·Piston Rings: Plasma-moly rings ·Camshaft: Hydraulic roller (.632” / .632” lift) (254 / 264 duration @ .050”) ·Lifters: Hydraulic Roller tappet ·Cylinder Heads: Aluminum Rectangular Port with a 118cc combustion chamber ·Intake Valves: 2.25” Stainless Steel ·Exhaust Valves: 1.88” Stainless Steel ·Valve Springs: Dual spring (1.540” diameter) ·Spring Retainers: Hardened chromemoly steel ·Rocker Arms: Aluminum Roller Rockers, 1.7:1 ratio ·Push Rods: High Performance (1-piece) ·Windage Tray: All new Screened and Louvered design ·Damper: High RPM torsional damper ··Ignition Timing: 36 degrees total advance ·Spark Plugs: R42XLS ·Fuel: 92 Octane

[TIMINATOR]

If you want to spend that kind of cash on a motor thats not machined or balanced to aftermarket specs,doesn't have a boat specific cam,and is not clearanced to run in a boat, GO FOR IT!!
When the customers bitch to us about the performance or lack thereof of the factory crate motors, we just smile and give them the estimate to remachine, balance and recam their new toy! We get about half of the work we estimate,and have had NO COMPLAINTS!! The comments usually run along the lines of "I'll never buy one of those again!" It seem that the only people we know of that are happy with the factory stuff are the guys that have never had a custom engine built or have had nothing to compare it to. Yeah, the guy that replaces his worn 454 with a crate 572 will be happy because he doesn't have any basis of comparison to what a custom engine would do. Also keep in mind that the factory engines aren't "seasoned", they are machined before the block takes a "set", the clearances will only get worse when that happens. The dyno specs are done while the engine is too new to take a "set", it goes downhill from there.... When the factory "seasons " the new blocks,lets you pick the cam,type of valves and clearances, and machines the motors to good aftermarket specs, maybe then I'm outta business, but not so far! :D TIMINATOR!!