572 / 720 Info

[RDavis]

I'm trying to find out how much extra HP using nitrous the 572 H Beam connecting rods will handle. I want to set up this engine with a NOS system direct port for a 200 shot. I have my 572 in my 1969 Camaro drag race car. If anyone knows what company makes these H Beam rods for GM Performance that is used in their 572 / 720 engines, would be a helpful start.
Thanks,
Bob

[jamz]

Bob .. thanks for posting on here as well. I'll see if I can get an answer for ya.

[pontiacjeff]

Why does anyone need an additional 200hp when you have 720hp in a 69 Camaro? You already should be in the 9's, I hope the car is set up for it! LOL! If you plan to run the NO2, I suggest a Carillo or Lunati billet rod. It is likely the "stock" rods are forged off-shore items like Eagle or Cat/Scat, machined by GM or someone for GM. They should be good for 800hp.

Really, though, the rod is more stressed by RPM than HP or TQ. I am running a stock cast Pontiac rod in my 750hp turbocharged 455, but it only turns 5500rpm and has lasted just fine. That same rod would snap in a heatbeat if it saw 7000rpm at stock hp levels.

It's all about piston speed (stroke vs. rpm). With a stroke of 4.375, the 572 shouldn't be turned over 6500rpm racing, nitrous or not (the engine peaks at 6250rpm, as advertised). If you keep it down below that, the "stock" rods will likely be fine, even with the nitrous. A set of Lunati or Carillos will set you back 1200 bucks or more, plus installation and re-balancing.

[RDavis]

Hello Everyone,
I appreciate all your help with my nitrous question with my 572. I do shift it at 6300 rpm because I know the max HP is reached at 6250. My Camaro weighs in at 3200 with driver. All motor and foot braking the car with a 456 gear we ran 6.00, 6.01. at 115 / 117 in the 1/8 mile with a 1.27 60 ft.
If I decide to change and run twin turbos instead of using the Nitrous, What engine changes would you all recommend? I know I will have to change the rear gear to a 410.
I want to run my camaro in a heads up class and it seems that I need to be in the 7's for the 1/4 mile class I want to run in. Any help with this issue will be greatly appreciated.
Thanks,
Bob

[BlackJack]

pontiacjeff is right. Nothing like stretching rods and slamming the pistons into the valves/heads. Things to look for with machined billet rods. Check that they're cross-grained caps with ARP studs, and decide on if you want floating pins or bushed, and also use Spiro-lock wrist pin keepers.

If I were switching to TT, I'd start with dropping the CR a little, but not too much, you still want some low-end power. Just remember, the turbos are adding compression just the same as having higher CR pistons.

Since you're wanting to give the turbos spool-time, make sure you get a TC stall speed that will get you into boost as your launching rather than halfway through your 60'. Example. My turbo spools at 3,500 RPM, so roughly 3000 stall speed is good for me. I dont want to be spooling while I'm staged or I'll start snapping shit. However, it only takes 500 RPM to get into hard boost, which is easy soon as you drop the brake.

I like your idea of switching from Nitrous to TT, nothing sucks worse than knowing you have to pay to fill up bottles every time you turn around, but the turbos cost you nothing extra for HP once you get them.

Are you planning on running them sequential or independent banks?

[RDavis]

Ok, I appreciate all the info. For the 572 / 720 create engine. If I do go with a twin Turbo setup, probably from Precision Turbo model #Garrett GT-5591 or the 5488, What rods, pistons, and crank would be best suited for 2100-2500 Hp? I have heard that a Sonny Bryant crankshaft is worth the wait which at this time seems to be aprox 16 weeks. What company would match up best with rods and pistons if I decide to go this route? Also, if propertly turned, How much hp will the 572 block with stand? This is a very impotant guestion and a must find out prior to doing any twin turbo setup.
If anyone can help me out with this info, I would really appreciate any help with this decession.
Thanks,
Bob

[RDavis]

Ttt

[RDavis]

Ok, Yes try this one. Since I can't find enough info to go twin turbo with the 572, Is their anyone out there that knows how much Nitrous the 572/720 engine can safely handle with a direct port system? I have heard a 200 shot works nice but how much more????

[The Big Al]

200hp shot is not a issue with the 572/720

Just for the record. The 572 Series engines have 100% ARP hardware.