2 bolt main block

I'm trying to figure out what a 2 bolt main block can take on nitrous. Will be in a foxbody and run 1/8th mile only. What I would like to do is build around 600hp and spray 250-300. Is that just unrealistic for a stock block? If so what are your opinions on adding the 4 bolt mains or would it be best to go with the a460? Thanks for the help or any info links you might have.

any of um as long as the tune is happy.

The best option is to go with the A460 Block, because you never just stop with only XXX Shot.......... But the factory block will get it done if you are good tuner and keep an eye on things at the level you talking about now.

^^What these guys said. If you are building from scratch, and can afford it now, the A460 block is worth the investment and piece of mind. However, I sprayed my little 466 with 250-275 tune ups quite regularly and had no issues until I got slack on my tune up. Then things went bad quickly  This was on a 2 bolt mained D1ve block. I've since sleeved that cylinder, filled the block and it's back living life in my new 488 A headed motor  

I have a 521 with 400 nx Gemini plate. Low compression 10.5 runs 5.71 121 1/8 1/4 is 8.93 151 3300 # 2000 mustang 1.29 60 foot on 275's

Thanks for the info guys.

521 I just went a 5.17 its a dove-a block with 4 bolt conversion

nitro717 wrote:521 I just went a 5.17 its a dove-a block with 4 bolt conversion

sounds nice! what the combo? 

Steel crank and rods good pistons 12.1, out of the box A-heads with a good vakve job. Stock suspension mustang on 275s. Just have to stay on top of your tune ups

Found out today the block we have now it a D1VE. If we decide to use it, would it be best to fill it and add the 4 bolt mains?

How big are you trying to go? Spraying a 521 is one thing with a stock block, spraying a 557 with a stock block is another. My 488 is a .060 D1VE block that I cracked, then put a sleeve in. We filled it just for the piece of mind with the spray. If it was all motor, I would have just ran it.

I'd like at least 521, maybe bigger. Don't want to go over what the block can handle.

Others will speak up, but me personally, if the block soni checks on the thick side of life, with a larger hit o nitrous, I would go up to at least .060 bore. I'm sure others have gone .080 safely with a conservative tune, but I'm just scared and feel like I'm living on borrowed time at that point.

I'd only bore it to whats required to clean it up, more metal is better than the little bit of displacement IMO

Sorry, didn't mean at least .060, meant max of .060. As Dave said, do the minimum for bore cleanup and see where you are. A 521 will be nice

The machine shop said it would take .040 to clean it up.

Going by the ci chart .040 over gives me options of a 503, 523, 547, or .060 over is 552.

Do you have any of the rotating assembly now? If you have to buy all the parts anyway, migt as well get as big as you can afford now. Wether it's a 4.3 or 4.5 stroke crank, price for forged will be close, then good rods and forged pistons.

Going by the ci chart .040 over gives me options of a 503, 523, 547, or .060 over is 552.

No parts yet.. just planning it out right now.

Then go big or go home

Id really like to do a 547 or 552 if the block will last.

A 552 with that 2 bolt main block will live a while, just be careful on your tune and not running on the ragged edge.

nhracer427 wrote:Id really like to do a 547 or 552 if the block will last.

I just built my 552 last winter it is a d9 block 2 bolt main .060 over,  4.5 stroke, 6.7 h-beam rods going to hold the rpm to 7000 to 7200 haven't run it but one time my trans was not up to the task it blew right throw it. It should be making some where around 750hp n/a I running alky no spray

can anyone elaborate on "be careful on your tune"? pretty generic statement, not being a wise acre, really like to know what to watch out for and what specifics to pay attention to.