Engine will be mega block 4.150 stroke 7.100 brooks aluminum rods. Compression will be flat top 13.5 Indy 440-1 heads, will have them flowed. What flow do we need? Davinci 1050 carb. Probably will be 4.375 or 4.400 bore what ever works more effeciently. Any and all help appreciated. Thanks Brian W.

There are a couple of books written on the subject. Might be a good place to start....

850HP from those pieces is easy...

Go with the bigger bore. Why not 4.5" ?

I would also consider a 4.25" crank for 540 cubes to use up all of the 440-1's potential. You could use the 4.15 stroke and wind it up higher if you have the right valvetrain, but a lower rpm motor usually lasts longer.

On the heads, Modern cyclinder head has a 345cc CNC port job that flows 382" at .800" lift.

Solid roller cam with around .750" lift and 284/288 duration at .050" should be enough. Could go alittle smaller on the cam if need be.

that should get the job done at 13.5 to 1 compression.

Andy's advice is good. Read a good book to understand the relationship between all the parts.

My 540 goes on the dyno this week, and should do 875HP or so with similar build, just a little more compression.

Cheers,

Arnie

http://www.mendezmotorsports.com/

ran 8.60 in his valient

lots of 10.0 cars with his power

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Go with the bigger bore. Why not 4.5" ?

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imho you're using up the block pretty quick going right to 4.5 but to each their own. i went 4.44 and this is with a KB that you can replace the sleeves in.

I guess that depends how many passes you get to make in a year, or if it sees a lot of street miles??

What is max safe bore on a typical Mega block?

For me it depends on whether Max power or max life is the priority...

Cheers,

Arnie

850 hp with -1's is not easy, but it is possible. I went with a 4.440" bore, 4.5" stroke and the heads flow in the 360 range. It's 15:1 compression, a good cam, headers and vac pump. 850 hp with b1's is easy

max bore...dunno guess it depends on the block. i know people go bigger than 4.5 but imho you're pushing it. at 4.5 you have less than 3/8 of an inch between the bores. wasn't really saying that for wear so much as damage if you should happen to get something in the bore, scuff a piston or the like. not that it will always clean up at 4.5 just that you have a better chance. for most people's application i would think the difference in HP would be worth not having to sleeve or trash an expensive block.

My 2002 build 4.39x4.15 503?! 440-1 1150 dom made 820hp 718tq. Thx Lynn Bakek...still leaks 5 and 5.

Hey Big cube, don't you think another 20cfm head flow would make 850 a little easier??

JameSC, I hear you on the damage aspect... Mine is a sleeved block, so i didn't worry about that, but you raise a good point on the megablock.

If you use a vacum pump and low tension rings, wear should be minimal, and i would rather buy custom pistons and only bore what is needed to get round again instead of taking .030" jumps during rebuilds.

Having said that you are right that he does not need to go all the way to 4.5 to start.

Cheers,

Arnie

When I first put the motor together I had it dyno'ed at Ritters. I had a dyno sheet that said 830 hp. The car ran a best of 9.16@147 carrying 2900#. The wallace calculators showed 745 hp by the ET and 757 hp by the MPH. I took it up to Dwaynes with no changes and his dyno showed 775 hp. I made a few changes to the motor and also added about 100#. I dyno'ed again at Dwaynes and got the 850 hp sheet posted above. That was a cold water, big number pull. At 150 deg it was more like 830 hp. The car ran a best of 8.94@151 with 3000#. The wallace calculators showed 830 hp by ET and 849 hp by MPH. I know I'm giving up some ET with my 60'.

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IIRC you were dynoed by Dwayne and he's posted HP and ET correlation for many combos in the past

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Numbers are all relative, the numbers that count are on the timeslip

That's pretty stout for -1 Indy heads. I'm not buying the flow numbers though. I hear so many on this site talk about huge flow numbers from these heads 415 from cab? My B1's flow about that much and that motor makes 1030HP on the dyno. I'm still testing a dialing it in, but it has run a best of 7.43@180.69 and it's 1850lbs. I think I'll be able to get it in the 7.30's but it doesn't confirm the dyno numbers, however, that was at 3650 corrected alt. Numbers are just that, numbers. ET and MPH counts.

oops!

My 528 build pushed the 3000 lb dart to 8.78, which I believe is about where you want to be.
I have a vacuum pump, but would go with a 4 vane instead of the 3 vane I have. I have 1.55 jesel rockers, but a better choice is 1.7 or higher.
Shoot for an installed height that will allow high lifts,(+.800) figure that out first.
The cam I had in the motor when it ran 8.78 was an Isky RR735, 280/288/110 with a gross intake lift of .765 intake with the 1.55 jesel rockers. I had it in at 110.
Guys are going faster with the more lift they put in the motor, so build it to a level you feel will live.
Valve springs ,lifters and pushrods have all come a long way, and parts will live longer at high lifts than in the past. You will need to do a lot of home work to come up with a good combo.
Terry Manton and his dad, who is a spring engineer, opened my eyes to a lot of information, as well as what I had been doing wrong in the past.
Run the lightest rings you can to reduce friction. I have .043 / .043 and 3/16 low tension rings, takes 22 ft lbs to turn over the shortblock on the stand.
I run alky injection on a 3x intake, 15/1 compression with 64 cc 440-1 heads.
The biggest bore up to 4.5 that you are willing to run will perform the best. I run a 4.15 stroke, 4.5 bore.
2 1/8 headers, designed to go over the chassis tubes for better flow out of the ports, allowing the 2 1/8 tube to work best.
Get some lift built into it, as a gross lift of .800 will really only be about .750 after lash and flex.
Good pushrods are important, and the bigger you can put in, the better. I now have Manton 1/2 inchers, waiting to see how well they perform compared to the heavy wall 3/8 I had.
I beleive a 4.25 with a 2.2 rod bearing, 4.5 bore motor would perform better than mine, based on a little lighter assembly and a few more cubes, pulling the torque a tad lower. This combo will have a torque peak in the neighborhood of 5,000 rpm.
I do run a very loose converter, 6400 stall, and it proved to be faster than the 5600 setup . Mine likes shifts at 7100 to 7200 rpm.
A good sidebucket pan and crank scraper will help you avoid the problems I had with the dragster style pan I started with. I will never run a high hp deal again without going with the best design pan I can find. Too much trouble with windage.
Finally, I had my heads changed to 2.3 intakes, Vs the 2.25 valves in it when it ran 8.78. The flow picked up about 5 percent on the intake, and having to reduce the exhaust to 1.78 didn't hurt at all. Time will tell if this was worth it. But I think If I had it to do over, that is where I would start.

I fretted over what bore to use till my machinist talked to me about all the rerings I could get at 4.500, then as the block wore there are options like .002 bigger pistons, same rings as the first, as they are.005 over. You can do this multiple times, making it a no brainer for me, as I doubt with my low number of runs I will ever get past the first set of pistons, let alone the third set.