I am thinking of building my next engine? Could anyone elaborate on the advantages or disadvantages of a 496 verses a 540? I am thinking a 540 but what is the dollar per horse power difference? And would it be a noticable difference between the 540 and the 496? I want to go solid roller and 11.5-1 comp, Aluminum rectangular port heads and so on. What would be the difference in HP and Torque? Would it be worth the money difference? Or is there any difference? The 496 would be a virgin 454 4bolt main, and the 540 would be a dart block.

Thanks

The big bore of a 540 or larger really unshrouds the valves and breathes much, much better than a 489 or 496. The aftermarket blocks are so much stiffer to help hold things in place at high revs and they're made out of a much harder metal so they don't wear hardly at all. You could probably sell the virgin 4-bolt block for about half of what it would cost to get into a Dart block. IMHO, that would be one of the smartest decisions you could make.
"Build it as big and strong as you can or you'll wish you had".
I know where there's a Big M that's available at a good price, PM or email me if you're interested. Good luck with whatever decision you make.

All else being the same, cubes are free torque/horsepower. I'd go for the Dart Block and 540 cubes.

can the car hook up the 496 let alone a 540, the rest of the car may be the limiting factor. Jim

For starters....there is a 46 cube advantage! You will feel that. And as mentioned, the breathing capabilities step up and if you go with the better block....youve got more chance to make bigger power easier.

I do agree though a lot of it might depend on the intended useage. With the quality of stuff out there anymore...you can make huge power with a 468. About another hundred cubes and things can get unreasonable if you take advantage of the inches(not that there is anything wrong with that). But if you build it to take use of the 540 inches....it can definitely make loads of power, and potentially a lot more than you need for whatever reason.

So this is just my opinion...but if this was just a street car that you want to be fast and race here and there....your probably just fine with the 496. It can be built to make way more power than most street tires/suspensions can deal with anyways. If the goal is to go as fast as possible and use that power at the track....the larger 540 has the advantage.

If you think about going big, i'd bore the bigger Dart based block out to 555" as that will make even more power than the 540 and cost almost the same as well as make the combination about 6-8 lbs. lighter from the extra bore. If you put in steel rods you can even put a 4 1/2" crank in and get 588" which will melt your tires in a hurry. The difference between the 540" we had and a 588" is substantial and the cost isn't much different. The big motor can tolerate way more cam, bigger heads and still be drivable. My son's big motor easily makes an extra 100+ H.P. over the 540 and is about 7-8 MPH faster in the quarter.

What is your intended uses? My car is primarily street. 540 is overkill and costed about twice as much. I was impatient and couldn't find a reasonable mark iv block. If it is a street car I would go with a 496. Also, I would use the Merlin III block over the dart if doing a 540.

Also, I would use the Merlin III block over the dart if doing a 540.

Why is that?

Thanks!!

If you think about going big, i'd bore the bigger Dart based block out to 555" as that will make even more power than the 540 and cost almost the same as well as make the combination about 6-8 lbs. lighter from the extra bore. If you put in steel rods you can even put a 4 1/2" crank in and get 588" which will melt your tires in a hurry. The difference between the 540" we had and a 588" is substantial and the cost isn't much different. The big motor can tolerate way more cam, bigger heads and still be drivable. My son's big motor easily makes an extra 100+ H.P. over the 540 and is about 7-8 MPH faster in the quarter.


Harold, is your son's 588 built on a low deck block or a tall deck block? I figure that a 4.375 stroke would be about max for a low deck.


Randy

How about something in between like my 511. Use a stock block with a 4.310 bore and a 4.375 crank. More cubes, same stock block. Not any cost difference.

Not any cost difference.

Except the custom pistons...

I think its pretty much a simple comparison. 540 = power, performance, strength, etc. 496 = cheaper, still great power.

This is a no brainer......as long as you can afford the better block. Agree also, go even bigger than a 540.
Don't worry about what the car can handle. Just make it work. If it won't handle a 540...it likely wouldn't handle a good 496 either.
Ron

If you start with a Dart Big M block and Dart aluminum heads and build a 540 you can make 700 hp and 650 lb ft of torque without too much strain. The dyno showed a nice wide band of over 600 lb ft from 3500 up to 6000 rpm and the best thing is the motor will run nicely on 93 octane pump gas.

Just getting ready to put it in as soon as the car gets out of paint jail. The motor has nice enough manners to be an awesome street car that with proper hook up we figure will run low 10's or maybe even dip into the 9's.

Yes, for a BIG ENGINE that still look's small for stealth, I like the 4.625" b x 4.375" s = 588" engine.

But if you don't wanna bore her all the way out the first time, build a 4.56" b x 4.375" s = 571.6" engine and it can be bored several times later if need be.

I'd use a 9.8" tall block along w/ custom, 6.45" long rods and needed pistons.

Should be a real winner, imho!!

pdq67

I'd be interested in a Big M block if the other guy wasn't ... RH

Very good thread. I also have many of the same questions. I have a Gen 5 454 4-bolt block that I'll be turning into a 496. I've also considered building it into a 540. After reading the other posts I'm wondering if a factory 454 block is good enough to do a 540. You folks with experience with this please let me know what the potential of my factory block really is. I know of several guys running my same block doing 496's with no problems, but do I need another block to safely go bigger? If so I'll stick with the 496 plans. Let me know before I buy a 540 kit. Thanks in advance. Doug.

I run a 11.5/1 540 merlin, afr335's, solid roller. Luv it but the gas mileage is ridiculous (prosystems dominator?).
If you plan allot of street a 496 with a 4150 and NOS sounds better to me.
If mileage means nothing, then go big displacement.
2cents

Davis95, you can't go that big with a 454 block. You'll need something with siamesed bores, a 502 block at the least. I wouldn't bore your Gen 5 block more than is necessary, they don't have quite as thick of cylinder walls as the older stuff. Every one I've seen has made a safe .060 over but at .030 over, you'll have better cylinder wall thickness for improved ring seal.
RonH, PM sent.

Very good thread. I also have many of the same questions. I have a Gen 5 454 4-bolt block that I'll be turning into a 496. I've also considered building it into a 540. After reading the other posts I'm wondering if a factory 454 block is good enough to do a 540. You folks with experience with this please let me know what the potential of my factory block really is. I know of several guys running my same block doing 496's with no problems, but do I need another block to safely go bigger? If so I'll stick with the 496 plans. Let me know before I buy a 540 kit. Thanks in advance. Doug.

You'll need a 4.5" bore capable block. A 502 production block, bow tie block, or aftermarket Dart or World products.
A 454 block is 4.250", and at most if sonic checked may take a .100" overbore. Which you could build a 505. I'd stick with a 496 and possibly leave a little room for rebuilding if needed down the road.

Bigger is better, the cost difference is negligible if you have to buy everything anyway. Go for it, be happy.

Thanks for all of your info Gary and Brian. I've done quite a bit of research on my engine build neglecting one of the most important variables...block limit. Now I know exactly what I'm doing with my block. This was a great heads up for me.