I just aquired a low mileage 6.4 block and crank. This is my first new hemi. I have a few questions:

How much horsepower can this block and crank handle?

This will be driven on the street-

What heads should I look for?

What compression Ratio?

How big of a cam can I run?

Can I disable the VVT?

How much can I expect a max effort new hemi make without a power adder?

Thanks, I am an old guy and am learning the new stuff.

Lots of power added guys doing 1000+. Max effort heads, look at Thiteks. Factory rockers are good for .650 ish lift I think, after that it gets very expensive, T&D are probably the best but pricey. Drag Pack intake and lots of $$$, please do a build thread!
Here's one that Hughes did using 5.7 heads:

http://www.hughesengines.com/TechArticles/21740hpgen3hemi.php

They made 740 hp with 13:1, DP intake and a 260ish @.050 cam. With Thitecks and more compression maybe 800? Cam er up and turn the piss out of it!

If your doing a max effort build, you should be near or exceeding 900HP.

There's a guy on here tha posts a lot on LXForums, has a very well built 440" (or is it 462"?) Gen III but I can't remember his handle, hopefully he chimes in.
BTW, to the OP, what does max effort mean to you? 15:1 compression? Max out heads etc?

Edit: Found his name, goes by 462Hemi. He's got a 462" Gen III that's daily driven. He uses Thiteks that flow 400 cfm@.6" lift.

Sixpackgut has a stout Gen III, I think 72Swinger does as well, they'll chime in shortly I'm sure.

Thank you both for the answers so far. I guess my max effort is not as much as everyone elses!

Let me put this on the table:

As much compression as pump gas (93) will allow


Large, radical cam for the old sound

Hellcat power without the blower.


Help me spec this out! Will the block and crank live at 700hp?

The Hughes Engines article above will give you exactly the power you want and can probably attain that at a reasonable rpm.

Set the crank aside and get a 4.05. Heads you want 6.4 or Thiteks in the 380-390 @ .600 area. Find a 6.1 or Drag Pack style intake,the right intake can make or break these things.

Okay, I have two questions:

I have been looking at intakes and the drag pak interests me as well as the 6.1. Could you cut down the carb base of the drag pak to make it fit under a b body hood?


Does anyone have a cam recommendation? The hughes article did not go into detail.

Call Eric Storms at BFNY, if hood clearance is a priority it's either a 6.1 or a Wilson.

Hey bud. Ok, here's my 2 cents for what it's worth. I drive my car every day on pump gas. I also have a lot of camshaft in it and am not scared by a rough idle.

The block will handle 1100rwhp, past that you will need billet main caps.
Mine was a max effort naturally aspirated motor that was really a little too far for daily driving. My motor dynos approx 700hp to the wheels through a automatic. That is on pump gas.
By my calculations that should be at least 850 flywheel hp. I run a hogan sheet metal intake on my motor. If I were in your shoes i would have the block sonic checked(most 6.4 have very thick cylinders and will take a 4.125 or some even a 4.155 bore). I would run the same crank I'm running now, a Callie's 4.200 stroke crank. This will give you at least 449 cubic inches.

The next step would be to call lsm and have a custom grind....they are one of the few that has a blank that will allow them to make a cam with real specs. Duration would be in the high 250s on the intake, high 260s on the exhaust. Lift should be .640-.650 depending on if your going to use a thitek or a Apache. The thitek is a superior head and will gain approx 20hp over the apaches. But you might find a deal on some ported apaches, that would be good too. Intake manifold.....I would use the Ritter racing/ muscle motors intake, dominator flange, tall plenum. I would NOT cut the plenum down. It's a good way to lose considerable hp on a hemi. Make it fit somehow. Compression ratio with a cam like that should be in the 12.8 to one range. With a cam that large the cranking compression will be low enough to work on pump gas with no problems. For reference, my motor is 13.1 to 1. This setup with a 2" header should easily get you in the same ballpark as my motor. Sorry for all the run ons. lol....

Rockers.....run stock or t&d.....the t&d are nice, but also $2500
Lifters, run the Johnson hylift oem replacement lifters.
You don't want the drag pack intake, it is cast small and requires lots of porting to make decent power. The Ritter racing comes cast much larger and will require little porting.
Timing chain.....stock, the only thing available.

This should net you at least 800hp and probably more. Let me know if I can help

Do you have any pics of your set up 462hemi?

Also how fast have you been?

I will post some pics of it tommorow evening. I'm having my buddy's shop reconnect the nitrous solenoids from the old system, but will have it back tommorow.

I made one trip to the track, hit 8k in the burnout box, ticked off the transmission control module and ultimately killed the trans. I have since replaced the trans and converter. I have not been back out yet, but on motor I expect it will go bottom 10s and lower 9s on the 300 shot. The car is 4375 with me in it. She's a big ole gal

WOW. 462 Hemi you have a pm

D-50.......That lil d50 in your sig looks nasty!! 1.33 short time??? Smallblock, pump gas and radials? Nice!!!!!!!!!!

Thanks, 462hemi... I just got the new M/T 315/60 Pro Radial tires I ordered a couple months ago, I hope it picks up some this weekend. May have to wait till fall.

Good information here. I don't want to hijack the thread but I do have a question of my own.

If someone built an engine like the example above, only with 392 cubes, how much power do you think it will develop?

Ported apaches, ritter intake, LSM cam of the above description, etc. All the same except for less cubes.

Typical gain from cubic inches is giver or take 1hp per cube. So you would take 59hp or so since the 392 is really 390ci. If you we're trying to get hp up with less cubes, you could run more camshaft duration and spin the motor to a higher rpm. There is folks turning these motors 8k with a hydraulic roller. Of course that does mean driveability and streetability would suffer......

462 Hemi, Whats your take on FI and 6.1 intake with boost? Would you be better to keep the cubes down?