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DCharger68
DCharger68 Reader
5/18/14 12:43 a.m.

I went and sold my 1977 Camaro LT project in favor of saving up for a Dodge. Apparently Dodge Darts (the old ones) and Plymouth Scamps are going cheap around here now. How hard would it be to make a B block fit one of these? And how much power is a B block good for compared to something like a 5.9 Magnum out of a truck?

oldopelguy
oldopelguy SuperDork
5/18/14 8:00 a.m.

If you are talking Scamp instead of Valiant you must be thinking 70's instead of 60's? There are kits for big block A bodies, usually with fender exit headers, so difficulty level is determined by your wallet.

I think that vintage has room in the tunnel for a TF727, which is pretty much the only transmission available for a big Mopar that doesn't suck or cost cubic dollars. Without overdrive you will want to build for torque and keep a relatively tall rear end for highway driving, which won't be a problem with those motors.

Type Q
Type Q Dork
5/18/14 8:12 a.m.

For a minute I was concerned you had bought a Maserati Bi-Turbo.

Rob_Mopar
Rob_Mopar SuperDork
5/18/14 9:21 a.m.

In reply to DCharger68:

OK, now you are talking my language.

I'm guessing you are looking at '71-76 Scamps and '67-76 Darts. The '73-76 ones will usually cost less than their earlier counterparts.

Back in '98 my buddy released the book Chrysler Performance Upgrades and covered the swap in one of the chapters in there. The book is out of print, but used copies can be found.

The B-motors (361-383-400) fit better than the RB (413-426-440). The lower deck height of the B-motor works better in the A-body engine compartment.

There are a few more options for doing the swap today than there were in '98. The easiest is the Schumacher conversion motor mount kit. It will let you drop a 383 or 400 in there on the factory K-member.

Exhaust can get expensive. The good headers start in the $550 range for TTI shorties, to $733 for long tubes. Schumacher's Tri-Y headers fall right between them price wise. Uncoated can be a little cheapter, but if you are spending that much on headers, get some sort of protective coating on them.

I have a buddy running a 496" B-motor (stroker 400 block) in a 4200 Lb Charger. With 3.23 gears and 30" tall slicks he runs in the upper 11's at the track. Stick that in a 1000 lb lighter A-body and Woo Hoo!

For a milder budget build B-motor, you can use '60's C-body log manifolds if you angle mill the driver's side manifold to roll the exhaust outlet in toward the motor a little more. It's covered in Frank's book.

With all that said, it's going to be cheaper to go with a 360 Magnum. Good used Magnum motors are still easy to come by. Good used B-motors are a little harder to find, and usually will need a full rebuild. The Magnum with a 4bbl intake, a cam swap (Comp 264HR-12), and cheap headers (buy the good ones later when you have the budget), you can be having a blast running 13's in the car with highway friendly gears. If you want more than that, it's just a gear swap away.

chandlerGTi
chandlerGTi SuperDork
5/18/14 9:26 a.m.

Not sure where you are but my friend has a 70 dart basket case in Danville il for sub-challenge money.

Fr3AkAzOiD
Fr3AkAzOiD New Reader
5/18/14 10:09 a.m.

My high school car was a '73 Scamp with slant six picked up in '95. My Dad picked it up from a dealer for $400. Kinda wish I still had it.

ebonyandivory
ebonyandivory Dork
5/18/14 10:21 a.m.

Go all GRM and build a turbo Slant-6 like a fabricator acquaintance of mine...

slantvaliant
slantvaliant SuperDork
5/18/14 1:42 p.m.

Lots of info on big block A-bodies HERE

DCharger68
DCharger68 Reader
5/19/14 9:20 a.m.

You guys are awesome. I wasn't expecting this kind of help on a mopar. I already have a 383/400 (not sure which it is yet) lined up to grab. But if a 360 magnum will hold up to any kind of boost I'd be interested in finding one.

MadScientistMatt
MadScientistMatt UberDork
5/19/14 10:01 a.m.
oldopelguy wrote: If you are talking Scamp instead of Valiant you must be thinking 70's instead of 60's? There are kits for big block A bodies, usually with fender exit headers...

Which are difficult to do well on an A-body. They're not like a Chevelle, where the inner fenders are splash shields. Darts use the inner fenders as the frame rails. While I won't say that you should never cut them, if you do, don't use sharp angle corners, and think hard about how you'll put the chassis stiffness back in. Better to use an underchassis exhaust if you can.

slefain
slefain UltraDork
5/19/14 10:13 a.m.

I measured the engine bay of my '75 Duster. A LSx will fit no problem...

SEADave
SEADave Reader
5/19/14 10:24 a.m.

Sorry to hear that you sold the Camaro, I was looking forward to having more 2nd gen content on the board. It sounds like you will have plenty of Mopar guys to help with the new project.

DCharger68
DCharger68 Reader
5/19/14 10:38 a.m.

In reply to SEADave: Well the good news is the girl I sold it to is a good friend of mine, an awesome body worker, and has deep enough pockets to bring the old chevy back to life. So I may still post pictures of it

DCharger68
DCharger68 Reader
5/19/14 10:45 a.m.
slefain wrote: I measured the engine bay of my '75 Duster. A LSx will fit no problem...

Those don't belong in a Mopar

slefain
slefain UltraDork
5/19/14 11:25 a.m.
DCharger68 wrote:
slefain wrote: I measured the engine bay of my '75 Duster. A LSx will fit no problem...
Those don't belong in a Mopar

I'm already running a GM HEI ignition, a Ford coil, and a Volvo cooling fan. And since it is a '75 Duster nobody will never scream that I ruined a nice car. I may throw Mustang wheels on it at some point.

Gasoline
Gasoline SuperDork
5/19/14 11:25 a.m.
DCharger68Reader said: I've done the unthinkable...

No....This is doing the unthinkable:

Vigo
Vigo PowerDork
5/19/14 1:06 p.m.

So just exactly how much power are you planning to make that you doubt a magnum 360 can take it?

Stock engines can almost always make a crapload of power on boost, but they vary wildly in how little detonation they can withstand. Most upgrades you do to a boosted motor have more to do with living through hiccups than they do with 'holding power'.

So, how serious are you about tuning? How much power a Magnum 360 can handle directly correlates to that answer.

DCharger68
DCharger68 Reader
5/19/14 4:41 p.m.
Vigo wrote: So just exactly how much power are you planning to make that you doubt a magnum 360 can take it? Stock engines can almost always make a crapload of power on boost, but they vary wildly in how little detonation they can withstand. Most upgrades you do to a boosted motor have more to do with living through hiccups than they do with 'holding power'. So, how serious are you about tuning? How much power a Magnum 360 can handle directly correlates to that answer.

I run around with two 700+ horsepower Chevelles and a 1000hp Nova. I'd like to make at least 600-650 at the crank

gofastbobby
gofastbobby Reader
5/19/14 4:53 p.m.

Doing that with chrysler parts is gonna cost.

Vigo
Vigo PowerDork
5/19/14 5:58 p.m.

Rpm costs money. If you want 650 n/a you're going to have to spin it faster, which means porting the heads, completely replacing the intake, probably getting a set of rods, probably getting higher compression pistons so your cam works worth a crap at low rpm with the carb you'll probably swap on. It's not going to be any kind of cheap to ger 650hp n/a on a 360 magnum.

If you boost it, you wont need as aggressive of rpm mods, but you'll probably end up porting the heads and replacing the intake and running a bigger cam anyway unless you want to try to make 650hp at 4500 rpm in which case you just need race fuel and a stock motor at 20psi.

DCharger68
DCharger68 Reader
5/19/14 6:29 p.m.

In reply to Vigo:

If I did go with a 360 I was gonna port the heads anyway, change to a 4bbl carb, swap a bigger cam, and throw on a turbo. The guys that have those high horse Chevies know how to build a blow through carb fairly cheap. But how reliably would the stock internals hold that kind of power?

Appleseed
Appleseed MegaDork
5/19/14 10:10 p.m.
slefain wrote: I measured the engine bay of my '75 Duster. A LSx will fit no problem...

You shut your whore mouth!

DCharger68
DCharger68 Reader
5/20/14 1:28 p.m.

Here's a thought. What about a 5.7 Hemi?

Appleseed
Appleseed MegaDork
5/20/14 1:44 p.m.

Yes. Dooo eeeet.

Rob_Mopar
Rob_Mopar SuperDork
5/20/14 1:54 p.m.

5.7 Hemi would work, but gets expensive too. I'd start with a 6.1 Hemi and go from there. None of it is going to be cheap, but the 6.1 has a few advantages over the 5.7.

If you are serious about that kind of HP, I'd go with the big block. Go with a 400 B-block, then a forged stroker kit to get you into the 500 CID range. 496" is pretty common with the 400 block based kits. Some good heads (Indy, etc), then add forced induction of your choice. Turbo in a big block A-body will be tough to plumb, but an ATI Procharger should fit just fine.

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