thats (500WHP) the point were they start splitting'em. i have not had personal experince with either. but they can split with less. there are people who claim they have run more than that with out problems. either way it's a gamble. when you get that high in power, you have to remeber that these blocks were never designed for it. if you have concerns about it, you might want to start looking into aftermarket blocks.

 

Of course the cheepest aftermarket block I found was the sportsman and that goes for around 800-900. It is a 302 with more material in the webbing and whatnot. Rblocks and Dart are the way to go if you have the money. Those babies will take over a 1000hp without blinking. I am building a 331 out of a stock block and am trying to keep the hp just over 400 NA. You can do a search this friggen block topic comes up every couple of weeks if not sooner.

 

So are the stock blocks good to 500 hp or 625 hp at the crank? Are we talking rwhp or fwhp? I've never gotten a straight answer on this. I have around 280 at the rear wheels which figures to about 360 at the crank. I was thinking about adding Nitrous this winter and figured a 125 shot would be pushing my block to its limit. 485 fwhp.

 

Depends on the build, the harmonics induced in the block, the duration of the abuse.
A combination with a turbo, that builds to that level of Hp in the 4800 RPM range will probably survive at 500 crank HP for a while. A system with a belt driven blower can split well below that. The fact that most belt driven blower systems aren't building peak pressure and there peak boost/peak HP until well up in the RPM window, causes the owner to run the engine in the 5000+ RPM range more often and for a longer period of time. On "STOCK" bottom ends, the balance is abysmal, and will lead to terrible harmonics in the block, easily beating the thing to death at the lower 450hp range. Aftermarket crank and internals with a quality balance job, and again we might look at something closer to a 500 crank hp threshold of failure. It isn't like a switch, where the first time the thing hits that mark it cracks, its a preriod of time at a certain vibration, and stress that causes the failure. Some people build 600hp combinations, and never really run the engine at a state where it makes the HP. Putting around on the street....... sure they have a 600hp combination in a stock block that lasts years, because they never turn any RPM, nor impart the stress.

 

Thats something to think about. I usually drive my car on the weekends and sometimes after work. Since I blew the first head-gasket, I dont really take it to maximum boost anymore. I am going to the track once, maybe twice when I get my blower back from Vortech just to see what it will do in the 1/4. Hope it doesnt split then.

 

Understood. I'm more concerned with the times I take the car to the track and run it to 6000 rpm. On the street I rarely see 3000 rpm. The bottom line is, we're talking fly wheel hp, not rear wheel hp. This is what I thought all along. Thanks for the reconfirmation.

 

That boost cooler will definitely put you over the 500hp mark. I have it on my car, best mod i've done besides from the supercharger

 

Stock roller 302 block, stock crank 50oz, decent pistons and rods. OTB TW's with Street Heat intake Vortech SQ 6.87 lower with 3.33 upper made 545 RWHP on a dynojet. Never had any problems at this level.

Andy

 

I run a stock 5.0 roller block with my combo which puts out 500+hp to the flywheel. I use a single turbo with a liquid to air intercooler and run 15-18 psi of boost.
Propane is my choice of fuel as it is rated at 105 octane and is relatively cheap compared to gasoline and it burns clean. I use two mixers (carbs) to get the required cfm that I need. I did experience one block failure but this was due to a defective harmonic balancer which threw the engine out of balance resulting in the crankshaft breaking in half and cracking the block beyond repair.
A good balancing of the rotating assembly is a must and I always o-ring the block and use ARP head studs with quality head gaskets for a good seal of the heads for the boost pressure.

 

just as long as its a safe tune 500-550 is a good place to stop on a stock block.. Friend of mine split a block in half pushing about 600 to the wheels with 20lbs of boost

 

You have to also remember that with a S/C you wont always be making 600fwhp. S/C's build their power with rpm. So as long as your not twisting the motor out you won't be make block splitting potential hp. So keep the rpms low and rev it out only when you have to and the block will hold up just fine.

 

I snaped a stock crank into 2 pieaces and it broke the stock block into two pieaces also.........Had a GT-40 intake with a set of Fully Ported Edelbrock Performer heads with a Crane cam and a V-1 T trim making 18-19lbs of boost......The motor lasted 3500 miles after putting on blower (6yrs ago)

 

i am at 473rwhp with a stock 302 block. I have a 3.33 pulley on my SC and i was thinking about changing the stock pulley to a smaller one to see if i can hit 500rwhp. I also have a main gridle and good internals, but it's a gamble with the stock block. I'm just going to wait and safe some cash to get a sportsman block and put all my good internals on it.

 

I split mine around the 450-500hp mark


Tyler

 

600

As of two weeks ago I had mine on the dyno.

601 rwhp and 558 rwtrq.

Yes, thats at the ground with a stock block,crank and rods.
All ARP bolts with a good balancer and only a windage tray.

89lx, dart iron heads, crane 2030 cam, holly systemax,
mac longtubes, 3" x-pipe, t-trim w/cogs @ 22lbs of boost.

The car ran 10:80 @ 134mph scalding the slicks.
2 people in it with a full tank of fuel @ Spokane raceway,
3200 ft elevation.

It may be a grenade but its been together for about two years.

A friend of mine made 520 to the ground with a similar combo
and split the block. It was a 60k mile stock block with no bolts
or balancer.

The tune and the balance is very important!!!!!!!!!!

 

Thanks for the input guys. I went to the dyno with a buddy of mine today and he made 558 rwhp as a base run. Fore some reason his a/f ratio went sky high @ 5k rpm and he never got to tune it or adjust timing. He has a 347 using a stock block. I know he has more power to make, but he has to figure out what the problem is. I think his Mass Air Meter pegged out or something. I have ARP Studs in mine. I'm going to take that chance anyway. If it splits, it will give me a chance over the winter to rebuild to maybe a 331 or something. Thanks fellas. Info. greatly appreciated.......

 

There are many people above 500rwhp on www.turbomustangs.com with stock lower ends.

Basically, don't detonate, don't spin over 6k rpms, and you can survive at 500rwhp for a long time unless you have a crummy block. Some people get over 600rwhp; however, the stock blocks don't seem to have very long life expectancies at that power level.

Of course, in a SC application you can subtract the power to spin the blower from the RWHP figures I am stating.