Small block, Big block, or Gen3 Hemi swap

Which engine combo is best NA or boosted

  • small block

    Votes: 67 39.2%

  • big block

    Votes: 45 26.3%

  • Gen3 hemi

    Votes: 59 34.5%
  • Total voters
    171
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zac_F71

zac_F71

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I am probably going to finish up my 71 Demon's chassis this spring, and leave an engine trans combo for when it's done basically

I have -

small block 360 (1979 360block .030" over, nothing else just a block)
68 383 big bock - also ^ the same just no machine work yet - have 440 crank for it

small block 727 that works
big block ^ that is getting a stock refresh w/ a shift kit

Both of the above will be turbo'd ^ but run NA for a season or 2 while a turbo setup is built

I have a few friends trying to convince me to go 5.7 hemi in it with a turbo

but after pricing a full ^ swap ($6,000 with a GOOD fuel system) it costs more to do so than a built small or mild big block - and you have a stock 5.7 runner with 100k on it, making 320whp, as where the LA big block would make 350+whp - and bolt in with a mechanical pump, and swapping a few wires around

For stock, for stock, for stock the Gen3 hemi will make the most power - short of a 340 or 426 hemi - but either of those are out of the question as they cost to much when I already have the above parts
 
If you keep talking this out with yourself, you may come up with the answer... Keep going...

Looks like you've already ruled out the gen 3 Hemi...
 
340 or 360 nothing like spanking big blocks with a small block..not a fan of the gen 3(mexican hemis..
 
That's what I friend has (650+hp 408 small block w/ nitrous) says he smokes big blocks all day..

I am really set on the big bock for mild power building, lower rpm range, and wow factor (with a turbo)

I wasn't a fan really either til I seen SharaDon Performance make 750whp w/ a basically stock gen3 5.7 (regapped stock rings, SRT8 intake), 78mm turbo, and E85
 
If you are into turbos, check out moran motorsports....
 
whatever seems to really be calling to you... go with that even if it is not the cheapest option.... best to build what you actually WANT and even if it takes longer its usually cheapest to build it once
 
Everyone has me convinced 5.7 at a the moment - lighter, better harmonics control in high hp applications (like I want), - truthfully every build will turn out to about the same cost -

with the big block being the most $$$$ adding aluminum heads, and such..

I plan to run 6cyl torsion bars as well..
 
zac_F71 said:
Everyone has me convinced 5.7 at a the moment - lighter, better harmonics control in high hp applications (like I want), - truthfully every build will turn out to about the same cost -

with the big block being the most $$$$ adding aluminum heads, and such..

I plan to run 6cyl torsion bars as well..
Click to expand...

i think you have your answer then lol
 
I know one of the guys at SharaDons and he's being pretty open with the build which is sweet

Use FAST EFI, GM style cable drive TB, 80lb injectors, SRT8 intake/rails, just need to figure out manifolds to make a turbo setup.. as theirs is all custom made to fit in a Mitsu Conquest
 
IF and that is just an IF

if I was building my car from scratch now with what is available and I hadn't spent all the money I have on my 340, headers, March pulleys, be cool radiator I would definitely put a 5.7, 6.1 or 6.4 in my Dart

If you plan on driving it you can get a 5.7 with low miles at a decent price in a wrecking yard or might even be able to by a whole vehicle that has been wrecked but drivetrain good

The small block or big block can make great power but gas mileage and parts available for the gen 3 will be much better in the future

It is your choice and your MONEY

When I built my car they were not available and I went with a 1971 340 instead of the 1976 440 I had and even had most needed parts to install.

Even today I'm thinking I should switch to a gen 3 Hemi but just hate the thought of what I have spent on my 340. It will come out this year or next to get aluminum heads and different cam so it will run on pump gas instead of needing to add 110 to the 93 pump gas to make it happy

Spending your money get a 6.4 crate and be happy, GO BIG OR STAY ON THE PORCH
 
what type of car is this?
do you want a car that rides handles and stops safely or is this one 1/4 mile at a time?
 
ir3333 said:
what type of car is this?
do you want a car that rides handles and stops safely or is this one 1/4 mile at a time?
Click to expand...
It's a 71 Demon - setup will be street/strip drag suspension, bigs and littles, 6cyl torsion bars, no cage full stock interior, stock FAST EFI 5.7/ manual shifted A727/ 3.23 B body 8 3/4 and a single 76-80mm turbo

Don't care much about MPG's - just want daily driveability with a ton of power
 
OK, here is my opinion. While big block A bodies are cool, I think for all around driving small blacks are best, You can easily get 450 HP out of a stroked 340 and still have a very streetable engine. I keep secretly hoping my 340 will blow up so I can put a stroked small block in mine.
 
I voted big block for the simple reason, there's no replacement for displacement. Example a turbo/supercharged 360 may make X amount of power, at some point, you do run out of cylinder space, so a 440 has much more maximum potential. I see this a lot, particularly in sled pulling which i follow closely, most mopars ran there that aren't 628 hemis, are 505 and 545 RB blocks with 14-71 super chargers, those 545s are making roughly 100 to 200 minmum more than the 505s, and they run the same class.
 
If you are going to turbo the car you are going to want to consider which engine will take the most power. I mean if all you want to do is make 500-600hp don't bother with turbos.

If you are going N/A the big block is very hard to beat, especially if it is going to be a street car.

harrisonm said:
OK, here is my opinion. While big block A bodies are cool, I think for all around driving small blacks are best, You can easily get 450 HP out of a stroked 340 and still have a very streetable engine.
Click to expand...

So your opinion is that a big block cubic inched small block is better for all around driving than a big block. I agree that a large displacement engine is best on the street. But why is the large displacement small block better?
 
The 5.7 hemi can take the abuse - plus I'm looking at it from a blown up engine point of view - as in do I want to spend another $5,000+ rebuilding a small/big block or $1,800 or so on a running motor..
 
Considering that stock new gen heads flow better than most aftermarket sbm bbm heads. It would be rediculus to run anything else. 6.q crank good rods and forged pistons with a mild cam is worth 1000rwhp out of a new gen hemi easily. Ported heads or thitek aftermarket heads and your way past anything not big hemi breathing abilities could touch. The wedge is a beast but drivability or mobility for gas mileage will cleary be much less with the old design engines.

Look into holley hp efi over the fast xfcry stuff. Really user friendly over the most others.
 
I couldn't answer because the poll didn't include a choice for the slant six.
 
I pulled the slant 6 out (still for sale).. I was thinking turbo the 6 but you have just about the same money into a 6 as a small or big block and have to turbo it to get any decent power out of it...
 
If you put a blower on stock 5.7 you will need head work and new rods I believe. I love driving my barracuda with a 5.7 I have no regrets, during the swap I had them every day
 
loganscuda said:
If you put a blower on stock 5.7 you will need head work and new rods I believe. I love driving my barracuda with a 5.7 I have no regrets, during the swap I had them every day
Click to expand...

Depends on the power level. Check out prochargers site.
 
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