Suggestions welcomed

[CSL DART]

I'm still in the game planning stages (mostly because I'm broke lol) of beefing up my 71 Swinger and I've finally decided on an earlier Magnum block 360 that should make between 450-500hp when it's done. I'm trying to build everything right just one time and end up with a bullet proof street car that I can drive the hell out of every chance I get and not break, maybe it's wishful thinking lol! I currently have a 904 transmission and will be beefing that up as well. My question I guess is more about the differential and the rest of the chassis. I'm inclined to do complete overkill on everything even if it takes longer to get the money to do so, just to build the car as strong as possible. Dana 60? I'd love to get some suggestions.... thanks in advance!

 

[KickDown]

Personally I think a Dana is too much for a relatively light car like the Dart. I would go for an 8 3/4 with 3.23 gears & an Eaton True Trac. That would give you a nice drivable street car. Also a beefed up 904 with 5 clutches in the high/reverse drum & a TF-2 will put a smile on your face.

 

[CSL DART]

Personally I think a Dana is too much for a relatively light car like the Dart. I would go for an 8 3/4 with 3.23 gears & an Eaton True Trac. That would give you a nice drivable street car. Also a beefed up 904 with 5 clutches in the high/reverse drum & a TF-2 will put a smile on your face.

Thanks for your advice! Yeah I've been reading and researching since posting the thread and all indications agree with you that the right 8 3/4 should easily handle the horsepower range I'm working in. Also seems like the 3.23 gearing will better suit my needs as I love driving on the freeway without a high revving engine. I'm slowly checking off all the different parts that will best work for my needs. I've also been considering a different transmission with overdrive to help get the best of all worlds. So far the only way it looks possible with a 904 tranny is by spending a fortune on gear vendors overdrive unit..... I'm sure there's cheaper options? Thanks again!

 

[67Dart273]

If you can't put an 8 3/4 in it put a Ford 9" in there. They are very strong, and VERY available. You can easily switch gearing just like an 8 3/4 and they "look enough" like a Mopar that most people will never know.

 

[AJ/FormS]

I have a first year LA360 that was built in 1999, and now has over 100,000 hard miles on her. But she's estimated at only 400/425hp.
It has an A833 with a GVOD and an 8.75 with 3.55s. To survive, it needed 1350 joints,U-bolt straps,and a modified CFII, with a regular 340 disc. I also installed a second mainleaf on each side, eye-to-eye. Yes the disc has a short lifespan, but it absorbs a lot of abuse.
The engine, with oiling mods, is bullet-proof, even with a FTH cam.
If you decide to try a manual trans;
Resist the urge to go A833od.I blew 3 of those up. Two were my own fault,as the OD gears are incredibly fragile. But on the third one I unzipped the input/cluster drive teeth,and was instantly walking.

 

[rumblefish360]

Another option besides the expensive gear vendors OD bolt on unit? SURE! But you still may not like all that is involved, so...

The Chrysler A-500. It is a 904 with an overdrive unit on the back end of it. It requires some cutting and minor hammering from what Ihave read here by the "Who has done it" on this forum. Do a search, you'll find it.

The GM 4 spd auto transmissions are also used by some. Also expensive with adapter plates for trans to engine.
Also done by a few on this site. Again, do a search and you'll find it.

 

[CSL DART]

Build A 500HP Capable 360 Magnum Short-Block On The Cheap! - Hot Rod Network. These guys at IMM are about an hour East from where I live and this build sounds about as good as I've found for what I'm looking for out of the car. The car was originally a slant 6 225, so I'm guessing there's not a lot of heavy duty anything from the drive shaft on back. Haven't pulled the numbers off the differential yet, but I'm going to soon. The 360 I have in there currently is a 79' block with a Holley 770 avenger carb, a Weiand 7510 intake manifold, the exhaust manifolds came off a 340, no headers but duel exhaust with an H pipe and turn down exhaust. It definitely has a cam that has the classic rough idle, but I don't know the specs yet. The 904 is a 75' and has supposedly been rebuilt recently. In short the car is fun as is but definitely has more bark than bite as far as performance goes. I'm definitely grateful for what I've got, but like so many of us, I need a little more punch lol! I appreciate you guys so much on this site for sharing your time and experience with a newbie like myself! The one thing I can tell you is I've been obsessed with Mopars since my first one ( 71' Challenger) I bought as a kid in 1987. Since then I've owned all A bodies: 69' Dart, 72' Dart Swinger, 73' Duster, 74' Dart Swinger and also a 76' Scamp. I'm thrilled to have my 71' and actually hang on to it this time as my life finally settled down about 6 years ago.... Thanks guys

 

[CSL DART]

If I searched for an early Magnum 360 block between 93'-95' would I be able to find one already married to an A500 tranny with overdrive? Just wondering if someone can help me narrow my search and possibly kill 2 birds with one stone... thanks!

 

[j par]

As far as Transmissions if you want bulletproof to beat on for fun you want a four speed! The 904 should just be rebuilt with good parts $120. Maybe a few things in there to beef it up for a few dollars and like was said at least a t2 if not at t3 transgo shift kit.
Here's the problem with an eight and three-quarter, it costs less or just the same to do a Dana 60. Because they're not so sought after or popular or whatever. And as far as being able to change your rear end gears yes it would be easier but nobody really does it for the most part. Now you will get one or two Knuckleheads on here they say they do but probably not too often. Really the only major easier part about doing that is you don't have to reset the Lash you can just put a different pumpkin in with different gears. Found a Dana 60 with good 4:10 gears that I'm currently using for $160 on Craigslist. I bought $75 end caps from dr. Dif. $300 35 spline axels with green bearings in any size shape or form. the nice part is this is something you can do slowly on a tight budget. For eight and three-quarter it's going to be hundreds and hundreds for anything even just a housing. And in the end you get a weaker rear end. If you want to ask me how I know after I blew up my 489 case 8 and 3/4 rear end that I just rebuilt 20 a quarter mile passes before. They do break or anything can be broken.

 

[CSL DART]

As far as Transmissions if you want bulletproof to beat on for fun you want a four speed! The 904 should just be rebuilt with good parts $120. Maybe a few things in there to beef it up for a few dollars and like was said at least a t2 if not at t3 transgo shift kit.
Here's the problem with an eight and three-quarter, it costs less or just the same to do a Dana 60. Because they're not so sought after or popular or whatever. And as far as being able to change your rear end gears yes it would be easier but nobody really does it for the most part. Now you will get one or two Knuckleheads on here they say they do but probably not too often. Really the only major easier part about doing that is you don't have to reset the Lash you can just put a different pumpkin in with different gears. Found a Dana 60 with good 4:10 gears that I'm currently using for $160 on Craigslist. I bought $75 end caps from dr. Dif. $300 35 spline axels with green bearings in any size shape or form. the nice part is this is something you can do slowly on a tight budget. For eight and three-quarter it's going to be hundreds and hundreds for anything even just a housing. And in the end you get a weaker rear end. If you want to ask me how I know after I blew up my 489 case 8 and 3/4 rear end that I just rebuilt 20 a quarter mile passes before. They do break or anything can be broken.

Thanks for your time jpar, I've read hundreds of your post on numerous topics and while I'm no expert, it's obvious that you're one of the more knowledgeable active members on this site. Honestly, all I've been doing since I got the car back in February is reading and more reading. Partly because I'm not yet financially able to do much of anything with the car and also just to aquire as much information as I possibly can. While I'm always the first to admit I'm not a mechanic I am old enough and smart enough to realize that not every thread I read is 100% fact. It is nice however to get several different opinions and come up with a reasonably accurate conclusion. I also realize nothing will replace hands on experience, but I'm just simply taking my sweet time enjoying the game planning phase I'm in at the moment. As I've mentioned in some of my post, the car is a lot of fun to drive in it's current state. What bothers me the most is on the freeway at 70 mph it is really working hard, wish I had a tachometer! Obviously smarter to hit the track, but I love to fly down the freeway at ticket speeds when it's not rush hour lol! It's like therapy for me and it always has been when I'm in a Mopar. I've gathered the 904 with the right parts would be just fine for the 450-500hp I'm shooting for, I just want some top end without beating the hell out of the engine, and came across the whole overdrive idea thinking I could have the best of all worlds. I was just noticing yesterday while reading and researching exactly what you're saying about the price difference or lack thereof between the Dana 60 and the 8.75 differentials! You're right again LOL! I've read a lot of guys also mentioning that the Dana 60 is too heavy for my little 71 Dart Swinger. I'm not worried about shaving seconds off my quarter mile time, I just want to build it right and build it once.If it costs more and takes longer, I'm okay with that. Thanks for your time!

 

[j par]

Thanks for your time jpar, I've read hundreds of your post on numerous topics and while I'm no expert, it's obvious that you're one of the more knowledgeable active members on this site. Honestly, all I've been doing since I got the car back in February is reading and more reading. Partly because I'm not yet financially able to do much of anything with the car and also just to aquire as much information as I possibly can. While I'm always the first to admit I'm not a mechanic I am old enough and smart enough to realize that not every thread I read is 100% fact. It is nice however to get several different opinions and come up with a reasonably accurate conclusion. I also realize nothing will replace hands on experience, but I'm just simply taking my sweet time enjoying the game planning phase I'm in at the moment. As I've mentioned in some of my post, the car is a lot of fun to drive in it's current state. What bothers me the most is on the freeway at 70 mph it is really working hard, wish I had a tachometer! Obviously smarter to hit the track, but I love to fly down the freeway at ticket speeds when it's not rush hour lol! It's like therapy for me and it always has been when I'm in a Mopar. I've gathered the 904 with the right parts would be just fine for the 450-500hp I'm shooting for, I just want some top end without beating the hell out of the engine, and came across the whole overdrive idea thinking I could have the best of all worlds. I was just noticing yesterday while reading and researching exactly what you're saying about the price difference or lack thereof between the Dana 60 and the 8.75 differentials! You're right again LOL! I've read a lot of guys also mentioning that the Dana 60 is too heavy for my little 71 Dart Swinger. I'm not worried about shaving seconds off my quarter mile time, I just want to build it right and build it once.If it costs more and takes longer, I'm okay with that. Thanks for your time!

I know I get pretty active on here but please don't let it mislead you into believing that I'm anything more than an adventure hobbyist. Basically just learning as I go along and maybe just a little bit better of the budget to allow me to make more mistakes. But I can tell you the car I have now came with a 7 and a quarter that I never ran because I already had four speed aspirations. I started off with a 8 and 1/4 that never broke with 355 gears in it but after I put a stroker motor in it I figured that was it. I sold it while I was still in good repair. And built that eight and three-quarter for over $1,200. And blew that up as I said within 20 passes. And I was right at about $1,200 with this Dana 60. I can personally attached that once the housings are all separated and all the axles are out and you just have an eight and three quarter housing with the part that holds the gears and all it's probably only a 20 lb difference at the most. The actual part that you're going to use. And mind you that way is right over your back tires where it's needed for traction anyways. I also forgot to mention that $160 Dana that I started with I was able to sell all of the brakes and axles for the truck stuff for $40 so it only ended up costing me a hundred and twenty. And I'm just saying this because you said bulletproof and doing it once the first time not 4 times like I did. If you don't mind that I don't go back and correct my voice command for the few things that I said wrong there I'll continue? If you like freeway driving with a tad of snappiness I would say 3:23's. A big Cam that makes vacuum. Refresh cheap home job rebuild on that transmission. That's probably the easiest part. once you tackle that easy Boogeyman it's all downhill...

 

[j par]

Remember once the Dana 60 is hollowed out and chop down it's really only bigger because it's that much stronger. The biggest hardest thing to research out find where you're going to do it and cost-wise is just getting the old ends chopped off and the new ends well done. Correctly! Once you got that solidified you're good to go and I wouldn't go any other way or suggest that to someone looking to do it right the first time and never look back.

 

[j par]

Youch the voice command killed that one too.

 

[CSL DART]

I know I get pretty active on here but please don't let it mislead you into believing that I'm anything more than an adventure hobbyist. Basically just learning as I go along and maybe just a little bit better of the budget to allow me to make more mistakes. But I can tell you the car I have now came with a 7 and a quarter that I never ran because I already had four speed aspirations. I started off with a 8 and 1/4 that never broke with 355 gears in it but after I put a stroker motor in it I figured that was it. I sold it while I was still in good repair. And built that eight and three-quarter for over $1,200. And blew that up as I said within 20 passes. And I was right at about $1,200 with this Dana 60. I can personally attached that once the housings are all separated and all the axles are out and you just have an eight and three quarter housing with the part that holds the gears and all it's probably only a 20 lb difference at the most. The actual part that you're going to use. And mind you that way is right over your back tires where it's needed for traction anyways. I also forgot to mention that $160 Dana that I started with I was able to sell all of the brakes and axles for the truck stuff for $40 so it only ended up costing me a hundred and twenty. And I'm just saying this because you said bulletproof and doing it once the first time not 4 times like I did. If you don't mind that I don't go back and correct my voice command for the few things that I said wrong there I'll continue? If you like freeway driving with a tad of snappiness I would say 3:23's. A big Cam that makes vacuum. Refresh cheap home job rebuild on that transmission. That's probably the easiest part. once you tackle that easy Boogeyman it's all downhill...

I'm not sure if you looked at the build attachment I posted earlier in this thread? I'm just curious to get your thoughts on it and how it would work with the beefed up 904 and the Dana 60 with 3:23's? I have my LA block, but everything points to easier horsepower with the Magnum blocks. We've all got our own taste with these cars and for me it's a little of everything. I generally like a quiet mostly original look (sleeperish) without a lot of frills like hood scoops, stripes or spoilers. As for the rest of the car I want to utilize some of the improved after market technology to get the car to handle, perform and be more reliable while still maintaining the classic muscle car sound....

 

[CSL DART]

I think you've solidified my decision on the Dana rear end! Keep in mind I'm prone to moronic questions from time to time, but I noticed just glancing in my year one catalog they weren't offering the 3:23's with the Dana. Is that only because most guys are generally building for more get off and quarter mile cars?

 

[j par]

I think you've solidified my decision on the Dana rear end! Keep in mind I'm prone to moronic questions from time to time, but I noticed just glancing in my year one catalog they weren't offering the 3:23's with the Dana. Is that only because most guys are generally building for more get off and quarter mile cars?

Likely also like you said a lot of people building for drag racing but even like mine that came with 410 gears they usually come in trucks which usually have those kind of gears. Look on dr. difs website And give him a call he's a nice guy and generally here on the forum easy to talk to and knowledgeable.

 

[CSL DART]

Likely also like you said a lot of people building for drag racing but even like mine that came with 410 gears they usually come in trucks which usually have those kind of gears. Look on dr. difs website And give him a call he's a nice guy and generally here on the forum easy to talk to and knowledgeable.

Thanks I'll do that! I was just looking and couldn't find anything higher than 3:54 gearing for it, but maybe he'll have an answer or suggestion.

 

[j par]

I'm not sure if you looked at the build attachment I posted earlier in this thread? I'm just curious to get your thoughts on it and how it would work with the beefed up 904 and the Dana 60 with 3:23's? I have my LA block, but everything points to easier horsepower with the Magnum blocks. We've all got our own taste with these cars and for me it's a little of everything. I generally like a quiet mostly original look (sleeperish) without a lot of frills like hood scoops, stripes or spoilers. As for the rest of the car I want to utilize some of the improved after market technology to get the car to handle, perform and be more reliable while still maintaining the classic muscle car sound....

It went back and forth over this Magnum thing myself. Now yes if I was to start all over again I would probably start with a magnum block to go ahead and get the roller cam availability that then I'm not any kind of fan of those pedestal rockers like Chevys have and oiling through the push rods. I have no experience with any of that stuff except for of course my wife's Durango LOL I considered it as an option for my truck but really just find out you have to put all your La stuff on the outside of it anyhow. It's like basically you get to the inner long block. Honestly like you said you're going for the old school look and feel and keep things on a budget and not complicated I would just stay with the LA 360. A lot of people will say it's easy to get a used Magnum motor and go from there and I'm sure that's a cheap way to go but also I'm talking from complete scratch also. Really it's a coin toss. And preference but I don't think you're going to get any more cheaper reliable power out of a magnum unless you buy it that way and roll with something thats used.

 

[j par]

Thanks I'll do that! I was just looking and couldn't find anything higher than 3:54 gearing for it, but maybe he'll have an answer or suggestion.

I'm sure you've researched and heard everybody said the same thing that a 3:55 or 3:54 is a good intermediate gear. You can definitely get on the freeway and for a good long time but for someone who's really into the freeway driving I would look for something a little more towards the 323. Again a 355 is a great gear especially for hot rods on the street and could do strip action.

 

[CSL DART]

I'm sure you've researched and heard everybody said the same thing that a 3:55 or 3:54 is a good intermediate gear. You can definitely get on the freeway and for a good long time but for someone who's really into the freeway driving I would look for something a little more towards the 323. Again a 355 is a great gear especially for hot rods on the street and could do strip action.

Hey thanks for your time tonight! I'm sure I'll run across you soon on here... have a good one

 

[j par]

Hey thanks for your time tonight! I'm sure I'll run across you soon on here... have a good one

Don't let my smart assness and jokingness elude from the fact that I am actually trying to help most of time so please take me with a grain of salt.

 

[j par]

I think you've solidified my decision on the Dana rear end! Keep in mind I'm prone to moronic questions from time to time, but I noticed just glancing in my year one catalog they weren't offering the 3:23's with the Dana. Is that only because most guys are generally building for more get off and quarter mile cars?

Also remember this is just one man's experience and opinion I like the fact that you researching and just use what I said is a tool that is any kind of factor guide please. It's been my personal experience I can't build more of a rear end for less than a Dana 60.