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Author Topic: Time to upgrade to a stroked SB  (Read 533 times)

Offline cuda346pk

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Time to upgrade to a stroked SB
« on: April 07, 2017 - 08:53:20 am »
Haven't been active for a while other than research. Car developed a couple problems and I have been buy working on my house to sell. However I can't stand the car to just be sitting right now.
Car is a 72 340 Cuda 4 speed, manual drum brakes, manual steering, no console, standard dash, B5 blue. I do have build sheet but no fender tag. I have some history of the car from its life in Mass..
Someone started restoration before I got it. It was advertised as non matching number motor which was fine as I have always planned to build it to drive hard. However once I got a vibration in neutral that goes away when I depress clutch. Then the motor started smoking a little I parked it and decided to clean the engine VIN to post in case it went to someone's e-body. Low and behold it does, mine. Obviously the guy I got it from didn't have any idea someone had tracked down the original engine for it. So now kinda unfortunately for me it is a complete numbers matching car, however nothing I can tell that was particularly special or rare on it.
Anyway I was going to build a 416 from the motor in it but an questioning that now as it is matching, I am also on the list for a Passon 5 speed - Hopefully this fall. and I plan to narrow my 8 3/4 to b body length and relocate springs to fit more tire.

Main question right now is opinions on which way to go motor wise. Find a hopefully good 340 block? Maybe a roller cam LA 360 to save cost and possible problems on converting 340 to roller? I hope to get as close to 500 rwhp as I can manage and a planning to use the 6 pack EFI from F&B/Fast with the Fast ignition also.

The car is in pretty good condition but I don't think I could get enough out of it to sell it and start with a different one as I have already done a lot of upgrades, which is ok as I never planned to sell it.
Firm Feel stage 3 P/S, 1.06" TB's, 1 1/4" fr sway bar, adj, strut rods, HD shackles, repaired all gauges, rebuilt 6 pack, clutch (may be my transmission vibration), vintage air a/c, viper front disks and generally lots of refurbish, clean up and got all odds and ends working.
David - In Georgia

1972 'Cuda In-Violet 340 6 Pack 4 Speed 3.91 Sure Grip - Finally, after 27 years of waiting and dreaming it is real. Now the fun begins!




Online 7212Mopar

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Re: Time to upgrade to a stroked SB
« Reply #1 on: April 07, 2017 - 10:56:54 am »
Power wise should be about the same and look the same. 416 sounds better than a 408 though. It also depends on the condition of your 340 block and if it has been bored before. You will not know until you open and test it. My 416 was just finished a few days ago and pull good numbers.
1973 Challenger Rallye, AT with 1971 340
2012 Challenger SRT8 392 YJ,  6 spd

Offline Bullitt-

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Re: Time to upgrade to a stroked SB
« Reply #2 on: April 07, 2017 - 12:56:55 pm »
I'd bag the OE stuff just in case & put in the Magnum block & whatever.. 
Being a '72 I doubt many would question your upgrade's & if the do WTH cares...LOL   
Wade  73 Rallye 340..'77 Millennium Falcon...13 R/T Classic   Huntsville, AL
Screwed by Photobucket!


Offline cuda346pk

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Re: Time to upgrade to a stroked SB
« Reply #3 on: April 07, 2017 - 01:04:27 pm »
Thanks Bullitt, Pretty much what I was thinking too. Also why I went with a 72. Am I better off with a Magnum block or the last of the LA's that were set up for a roller cam? I would prefer to use shaft mounted rockers I believe, although it won't be a high revving motor so maybe not as crucial of a point. I am pretty sure you can use LA heads on a Magnum block as long as you deal with the valve oiling situation.
David - In Georgia

1972 'Cuda In-Violet 340 6 Pack 4 Speed 3.91 Sure Grip - Finally, after 27 years of waiting and dreaming it is real. Now the fun begins!

Offline Bullitt-

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Re: Time to upgrade to a stroked SB
« Reply #4 on: April 07, 2017 - 01:59:09 pm »
I've never heard of using LA heads on a Magnum .. these guys don't think it's the thing..
http://www.hotrod.com/articles/hrdp-0804-small-block-mopar-engine/

They got 448HP with minimal upgrades.... (doesn't read like it's even stroked)
Don't know why you want 500 unless your going racing or just Hate your rear tires...

I'd be looking for max torque as early as possible for a street motor that's not gonna be revved over 5K
 Torque is what turns the world & gets you goin quickly not HP.
« Last Edit: April 07, 2017 - 02:02:07 pm by Bullitt- »
Wade  73 Rallye 340..'77 Millennium Falcon...13 R/T Classic   Huntsville, AL
Screwed by Photobucket!

Online 7212Mopar

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Re: Time to upgrade to a stroked SB
« Reply #5 on: April 07, 2017 - 03:46:43 pm »
Need to have both TQ and HP. You don't want to get passed after the car starts moving.
1973 Challenger Rallye, AT with 1971 340
2012 Challenger SRT8 392 YJ,  6 spd

Offline Chryco Psycho

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Re: Time to upgrade to a stroked SB
« Reply #6 on: April 08, 2017 - 08:07:48 pm »
I would use a 360 roller LA head block stroked to 408 with Air Wolf heads & a roller cam  :2cents:

Challenger - You`ll wish You Hadn`t

Offline xtopfuel

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Re: Time to upgrade to a stroked SB
« Reply #7 on: April 08, 2017 - 08:59:31 pm »
I agree store the 340 build. 408 out of a 360

Offline cuda346pk

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Re: Time to upgrade to a stroked SB
« Reply #8 on: April 12, 2017 - 11:28:22 am »
I would use a 360 roller LA head block stroked to 408 with Air Wolf heads & a roller cam  :2cents:

This is the route I was leaning towards going, I totally destroyed 1 340 block years ago when I was 16 so I would prefer not to risk another one.

Bullitt I know 500 is a lot of HP  but I plan to build it like you are saying, lots of torque down low and not have to run it over 5000 rpm. It is a street car but will play some at both dragstrip and Road Atlanta, plus the mountain roads too!
David - In Georgia

1972 'Cuda In-Violet 340 6 Pack 4 Speed 3.91 Sure Grip - Finally, after 27 years of waiting and dreaming it is real. Now the fun begins!

Offline Bullitt-

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Re: Time to upgrade to a stroked SB
« Reply #9 on: April 12, 2017 - 04:17:26 pm »
 :2thumbs:      :burnout:
Wade  73 Rallye 340..'77 Millennium Falcon...13 R/T Classic   Huntsville, AL
Screwed by Photobucket!

Offline burdar

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Re: Time to upgrade to a stroked SB
« Reply #10 on: April 12, 2017 - 04:32:07 pm »
If you are going to store the original drivetrain and start from scratch, I'd seriously look at a new hemi swap.  I don't think there is a huge price difference.  I think you can still hook up your 5-speed to the hemi as well.  You can make stupid power with a new hemi and still have good mileage and street manners.  Doesn't Mopar Performance have a new hemi crate motor coming out soon?  I think it comes with the computer and wiring needed for the install.

If I was starting a new project, I don't think I'd waste my time with an old SB or BB.  :2cents:

Offline cuda346pk

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Re: Time to upgrade to a stroked SB
« Reply #11 on: April 25, 2017 - 03:20:02 pm »
If you are going to store the original drivetrain and start from scratch, I'd seriously look at a new hemi swap.  I don't think there is a huge price difference.  I think you can still hook up your 5-speed to the hemi as well.  You can make stupid power with a new hemi and still have good mileage and street manners.  Doesn't Mopar Performance have a new hemi crate motor coming out soon?  I think it comes with the computer and wiring needed for the install.

If I was starting a new project, I don't think I'd waste my time with an old SB or BB.  :2cents:
I briefly thought about this, but first problem is my current 23 spline 4 speed wouldn't handle it and I am being told probably still 12 months out on the 5 speed. Then I am not sure the Hemi will fit with stock style front suspension and I don't really want to go coil over and rack/pinion. I will start looking for a good candidate LA/roller 360, 89-91 if I remember correctly. Maybe I can find one with its serpentine drive still in place to convert to at the same time.
David - In Georgia

1972 'Cuda In-Violet 340 6 Pack 4 Speed 3.91 Sure Grip - Finally, after 27 years of waiting and dreaming it is real. Now the fun begins!

Offline kielbasa

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Re: Time to upgrade to a stroked SB
« Reply #12 on: May 01, 2017 - 10:41:03 am »
go 360 LA roller block, BPE 4.125 crank (with his rotating assembly) and his heads......you will have a hard time beating that combo bang for the buck........

Offline burdar

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Re: Time to upgrade to a stroked SB
« Reply #13 on: May 01, 2017 - 12:40:26 pm »
Engineswaps.com has mounts that will mount a new Hemi to the stock K-member...

Offline Chryco Psycho

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Re: Time to upgrade to a stroked SB
« Reply #14 on: May 02, 2017 - 09:16:36 am »
gen2 or 3 Hemi is easily done & yes the "weak" 23 spline trans will be fine

Challenger - You`ll wish You Hadn`t