440 or stroked Big block
OR
5.7-6.4 modern hemi

Which is cheapest to hit the Hp goal of 650-700HP?

I think there are some build ups in the tech archive that will get you where you want to go.

Yes I have read them just wanting to know dollar for dollar which is the lowest cost option to achieve the goal. Big block or new hemi?

Never built either, but B/RB speed parts have been around for so much longer so my gut tells me it would be cheaper and easier than the hemi to get 650 hp right now.

Used 5.7 Hemi engines are $1500-$2000 on CL, but they don't make 650 hp either. You would need a power adder, or a larger engine as a starting point.

If you post this in the race-only section you may get some more experienced opinions.

Most likely a B/RB. 650 horespower doesn't really have a low cost option. Lol. Or not one that will live very long!

Your goals are achievable with the correct good parts, a good sonic tested 400 block, 4.250 stroke crankshaft kit with the longest forged H beam steel rods you can use, 10.0 to 10.7 to 1 compression with a set of the new Trick Flow 270 CC heads and a matching intake manifold with a 1000 + CFM carb and a good high lift medium duration (245 to 265 @.050 with a LCA from 105 to 110)camshaft and rocker arm kit
My first 400 stroker (511 C.I. 4.375 bore with 4.25 stroke))had 9.25 to 1 compression with a set of mildy ported 906 heads with bigger valves and a low deck six pack set up. That combination made 612 HP at 5500 RPM and 644 Ft. Lbs. torque at 4500 RPM, I put that motor in a 3450+ Lbs. 1971 Duster that ran 10.69 at 124.+ MPH through the complete to the rear bumper 3.0 inch exhaust system on with the air cleaner on
A later change to a set CNC ported Eddy RPM heads picked it up 10.49 at 127+ MPH on Oregon 91 octane pump swill
That was back in the early to mid 2000 so don't ask me about the prices now
I beat the snout out of that motor, I did make a lot of changes to it in the ten years I owned and raced it but it was the same cam and lifters and bore size with the original pistons when I traded it off for my current race car
The cheapest way to make your HP goals may be a used lat emodel Hemi and a lot of NOS, no way to tell how long a stock motor will take 200 to 400 HP of NOS
A decent built pump gas BB stroker motor will make that amount of power for a long time, trust me on that

Personally I'm thinking the 3rd Gen hemi is the way to go. The heads supossedely flow over 300 cfm in near stock trim so they should easily support over 600 hp NA. A turbo or supercharger and you're there.

I'll throw in my two cents. I'd go with a 500CI stroker kit in a 440. Some aftermarket aluminum heads, good intake and carb. I am not an expert at recommending cams, so I will delegate that to someone else. I would think nothing too radical would be needed in the cam area to get to 650 hp. But, if you are going to stroke any block (RB or Gen II hemi), might as well get the most cubes as possible.

After reading it cost $8-10k to build a stock 383 on the other thread, why bother.

You can buy a brand new crate 707HP Hellcat motor for $15k.

https://www.ebay.com/itm/Dodge-6-2L-Hell...m4383.l4275.c10

That 10k figure includes ancillary items as well for building old iron where the hemi doesn't. I just built a 512 and it cost me just a bit over that out the door. That 15k Hemi still needs a harness, fuel system, computer, pan and exhaust. All that stuff being for late model is tons more expensive than it's old school equivalents as well.

Cost parity is coming, but I don't thinks it's there yet.

First question, what's your budget for the "complete" motor?
Carb to pan, headers, distributor, plugs, wires, oil,..... Everything.

Then, is your car currently equipped with a fuel and cooling system capable of supporting a 650hp motor?

If not, are those upgrades budgeted separately...... Or do they need to be included in the "engine" budget?

The question boils down to this. Irrespective of any other factor is it 'cheaper" to build a BB or BB stroker OR new hemi to support a 650-700hp target STREETABLE aka hot rod, restomod or whatever you like (in other words not a full time race car)
This is more of a what if or a bench racing question not a How do I build... question.

I'm pretty sure I'm in the minority here, but a good solid 440 (forged pistons, maybe a girdle and some good heads) with nitrous oxide will get you there. You will be right on the limit of a stock block, but the car can easily be streetable since you won't need a huge cam.

take a look at engine masters they did a show on the 5.7 with mild ported heads and a supercharger with ait to water intercooler that made close to or better than 700 hp frieberger and dulsitch(sic)

"Cheapest" is probably a used 5.7/6.4 with a turbo kit.

The LS guys make more than that with used 5.3's with turbos on them.

Kid at work has a 6.4 challenger one day we were looking at the kenne bell for it. Seems to make good power like 750 or something like that. For a minute I thought that would be a cool setup in an old car, and maybe cheaper than a hellcat crate? But those G3 cost so much to get setup in the car it's crazy. I say for 10 grand you can do a bb with 440 source stroker with trickflow heads and intake. All new parts, make hellcat power. Of coarse it won't have efi and the driveability.

I did a mild, street driver 505" 440 for right at $7,500.
Molnar crank and rods, Mahle pistons and CNC Stealth heads. It's just under 600 HP but more than enough for the street and a blast at the track!

You save a lot of money if you can build it yourself.

I think MarkM hits the nail on the head first. Older car will cost so much more to wire it up with the proper harnesses, etc. to support the newer Hemi.

Next I agree with Cab Burge. Stroked 400. The more I read about stroking a 400 the more I like!

I would think a a Gen 3 with a turbo kit also, but you could also easily run the bill up to equal or far more than your basic B/RB would be to make the same power. It all depends on your approach. But I think it can be done cheaper. The main disadvantage that you have with a B/RB is its already going to need a rebuild unless you find a good engine for a song. Everyone thinks their junk 440 that burns oil and has 100 psi cranking compression is worth what those 5.7s on CL cost...

the real question needs to be how much work can you do yourself? can you weld up a turbo kit? have access to a cnc? have access to tuning software? have a box of carb jets and lots of free weekends?

I think you're looking at the b/br combo to be your best for the buck. plenty of used speed parts on the market to get you to 650hp.

Gen 3 for sure. Just because you can pick a complete one out of a wrecker and more less supercharge it etc. Look at the ls swaps. Nobody is picking 350’s anymore to hotrod.

I know that it wasn't in the options above, but why not a well build 5.9 LA or magnum and turbo or supercharge it? I wouldn't think that you would to far away from the goal of 650. Plus parts for these are cheaper and more plentiful then the Gen3 parts.

I don't have the answer. I just started looking into Gen III stuff.

I think if you are working on an older Mopar, Then a stroked big block may be easiest because it will fit the stock K-member.
I think either option may be close in a hp per dollar for the engine, with many differences in fitment, accessorys and drive, and fuel system.

If you want modern EFI, coil near plug, serpentine belt drive, with high output alternator, A/C, and power steering, I think starting with the GenIII will save money, but fitting the engine to a old car and the computer/electronics may add to the costs?

A big block with carb, and minimal accessories likely will be less expensive, but converting the old big block to modern accessories and port EFI can be expensive.

In my case, I overspent converting the 505" stroked 440 in the convertible to port EFI and Billet Specialities Tru-Track.
The Tru-Track serpentine belt system was over $3,000 plus all the lines, remote reservoir(s), and other stuff likely an additional $500?
The Edelbrock XT EFI was about $4,000 and I ended changing out the ECU, fuel pump and such to about all I really used with the intake, TB, and sensors. The total cost got out of control likely an additional $3,000 on top of that for the FAST XFI 2.0, dual sync dist, wiring, EFI fuel tank and such.

On the other hand, I picked up a 80,000 mile 2008 6.1L Hemi with NAG trans off E-Bay for $4,000 with all the accessories, manifolds, stock wiring harness and computer. I think I spent $200 on a new electronic accelerator pedal and transmission shifter. I haven't decided on what to do with the electronics yet as more options are starting to come out. Looking at the Holley Dominator EFI?
The conversion K-Members are a bit pricy. The RMS alterKtion K-member / handling suspension kits are around $5,300+ brakes at $700 to $2,000.

Original scenario said for a driver with part time strip use.

Just how "driveable" do you think a stoker 440 with high compression will be?
Gen3 on the other hand would make the Power Tour with no issues.
Gonna have AC on that stroked 440?

I think it will depend on what you have available to start with. If you have a base of anything, the trip to 650 HP will cost about the same money. Being able to actually use the 650 HP may change everything, and how you intend on using the 650 HP also has to be accounted for. How long you expect the motor to live will have a dramatic effect on the cost, regardless of what you start with.

If your starting with no motor, but have a drag car chassis available, you use the motor/trans that fits the easiest in the car. It would be much more easy to get 650 hp hooked up going down a quarter mile strip then it would be to get 650 hp hooked on on the street while expecting to drive across the country. 650 hp looks a lot different if you put that into a car on a NASCAR track, or a mud bog truck.

Otherwise, have fun. Gene

there is no right answer. Built to take the power with maximum amount of reliability for the street would probably be a turbo of some sort. They only make power when you tell them to. LA motor with a turbo would be cheapest probably.

I will add it depends on what character you want the car to have.

The gen 3 hemi can make the power NA. The heads have the flow potential and the block can take it. You just have to spin it up... torque is limited by displacement.

The BB stroker can have lots of mid range torque aided by higher displacement. It may feel stronger in normal driving.

Turbo or supercharger options on either one can increase both torque and power. I do not think these are budget options however. Also there may be trial and error involved (eg. trashed long block) which can increase cost significantly.

That makes a huge difference if you can do your own work. I have to laugh at some of my friends who are mechanics for a living. They seem to be happy being the parts replacing mechanic where they slam parts on cars and make all the money they can but as soon as a real problem job comes in their shop they say.....take it to the dealer. And they pay a machine shop to built their complete eng ??? Why would you have a trade as a mech and pay someone else to build your engine ?? Myself I became a mechanic/tech so I could learn to do everything on a car and I sure as heck did not become a tech for a living to not build my own eng. I can see if your not a tech/mechanic but I do all my own work that I can which is most other then some machine work or head porting which I have done but I am no pro head porter and I now have back problems that mess with bending over a bench.
But if your are able to do most or all of your own work you will save a ton of money. I know for my stroker kit , cam , heads and little things I spent at least 7k and that's just parts. If I had payed to have the eng built that's most likely somewhere from $1500 on north.


The other question is are you talking naturally aspirated eng or do you plan on a power adder as that makes a big difference. If N/A I think the bigblock B/RB stroker is one of the best bets. But if you are including power adders heck a stock 5.7 to 6.2 Hemi with a supercharger on it should be right there.
Or look at what DVW's son (I forgot his handle) has done with a mild 360 and twin turbo's on his 62 Mopar. I don't know how much he has in it but his car runs mid 9's and makes a lot of power. Myself I like the N/A bigblock stroker eng but I grew up in a world where you just did not see power adders that much on muscle cars. But in todays world you can make big power fast with power adders and the new Hemi eng seems to be strong enough to stay together with superchargers slapped on them that are basically stock.
Its close without added up all the figures but I would consider just what car and eng combo you like and what you plan to use the car as. Me I love the 60's and 70's muscle cars with naturally aspirated engines and that's the way I would and did go but you should consider what type of car/eng combo you like also. Good luck with it. Ron

Instead of 650Hp would a better question be what is it going in, and how fast do you need to go? 11.50 and faster requires a cage and other stuff that can make the car a pain on the street.

My observation with power adder cars is that no serious bracket racer here seems to use them. Too sensitive to heat fluctuations and harder to dial in. Cars that do have them are fast, but seem to struggle going back to back on the same dial in. Most of the guys who have turbos, blower, + nitrous are the test and tune guys who just want to let it rip once every few weeks for fun. The guys who are more race than street all have simple single 4 barrel big blocks. If it breaks they can get it going again before the next race with minimal downtime and expense.

I have a 645 hp 500" 440 that will be street driven, it has iron heads so it has a stout cam and I know it will probably get less than 3 mpg on e-85. This combination has been together for twenty five years but if I was to start from scratch it would be a gen 3 turbo. It would be nice to have more drivability....10 , 15 miles per gallon in addition to more power.

What iron heads are you running at that power level?

An old pair of 915s, 2.18/1.81. 67cc

Nice!

You can build an Indy head stroker for under 10K that will last forever if you do your own assembly carefully. It can be done with a flat tappet cam but a roller would make the 650 number easier and possibly live longer. The roller would probably bump the price over 10K for the package to support the roller.
You don't really need external oiling with the correct rod and crank choice so that would save a bunch of dough.


Gus