Drive Train Upgrade Suggestions

[Mopar Virgin]

Just purchased a convertible '68 Barracuda with a Slant6 as a project car sight-unseen.

Up-front, I am not a mopar specific enthusiast and this will be my first full resto-rod project that a friend (not a mopar guy either) who's done a lot of car projects will be taking on with me. Thankfully we have a common close friend who is a mopar fanatic and will help us a great deal, but I'd like to get input from as many people as possible.

I anticipate the Slant6 engine is under-powered and would appreciate people's thoughts on engine alternatives that don't make the car difficult to control or dangerous (e.g. no 440 block for me). Likely will put an automatic transmission with it so my wife will drive it on long trips.

Intending to lower the stance, hot-rod it a bit, use non-traditional mopar paint color, and will put some meat on the rear end (e.g. not taking a "restoration" approach). Might be open to a fuel injected engine and modern transmission too. Appreciate any input people have on the drive train related to balancing power with the reality that burn-outs, fish-tails and street racing are a thing of the past ... but we still sneak it in once-in-a-while !!!

 

[jazak5]

being your starting from "scratch" can't go wrong with a 408!! with a warranty! rest of the parts mare somewhat reasonable beside the 8 3/4 rear...
QA1 K frame with rack and pinion steering
and up graded brakes

solid modern upgrade...

just keep in mind were not fords or chevys our stuff takes more time to find and $$$

IMO
Chrysler Compatible Crate Engines

 

[69cudaownr]

Oh oh, You didn't give a budget. My thoughts would be a 5.7 Hemi drivetrain to an 8 3/4 rear, (you likely have a 7 1/4 rear in there now). Stock 8 3/4 rear can handle 275/ 40R17 which is a fair bit of wheel without customization. Make sure you have large bolt pattern axle in the 8 3/4 for better wheel options. Small bolt pattern wheels are scarce and expensive.

 

[Projectile Dart]

A. Welcome to the site
B. Maybe give some ideas as far as your budget goes/time you expect to complete it. These cars can fit just about any motor ranging from your slant 6 just a little warmed over to a really hot stroked small block (people have stuffed monster hemis in A bodys but you said you don't want to go big block so I'm assuming no hemis either)
What are your expectations or limitations

P.S. If you take a look at the photo garages here you can find a lot of inspiration if you aren't even sure what you are looking for now

 

[74Scooter]

being your starting from "scratch" can't go wrong with a 408!! with a warranty! rest of the parts mare somewhat reasonable beside the 8 3/4 rear...
QA1 K frame with rack and pinion steering
and up graded brakes

solid modern upgrade...

just keep in mind were not fords or chevys our stuff takes more time to find and $$$

IMO
Chrysler Compatible Crate Engines

Shame Blueprint stopped doing LA's... all their SBM items are Magnum based now.

 

[rumblefish360]

Shame Blueprint stopped doing LA's... all their SBM items are Magnum based now.

It’s just to hard to keep a supply of good cores to build from. There not littering the streets and junk yards anymore but the Magnums are!

 

[rumblefish360]

@Mopar Virgin LMAO! Welcome aboard!

If it were I going this route, a 5.9 fuel injected pirated from a low mileage wreck would be the power plant. Look for a 2 wheel drive truck as the transmission is something you can use and fit into an A body. There are threads on that well documented here.

I’d keep the fuel injection. So get the computer.

As said above, the 8-3/4 is pricey. Some have used the Ford 8.8 instead. (Comes with disc brakes already!)

As far stance and tires used, if you like’em wide out back, a spring relocation kit & mini tub kit to move them into the subframe rails will allow a lot of room for wide rubber.

Cal track split mono springs can be ordered an 1 or 2 inches up or down or stock. But! If you use there bars, they need to know if your running the springs in the stock or moved in location. While the QA1 front is an interesting upgrade, IDK if I’d spend that kind of money.

 

[Krooser]

GE J-47 jet engine

 

[James Clews]

Get an aussie 265 Hemi six. The latest engine on the dyno produces about 450 rear wheel horsepower normally aspirated and that guy is building a stroker version out to about 290 cu ins and will put out a shed load more hp. They take up so much less room than a V8 and are way lighter.

 

[Ted265]

Get an aussie 265 Hemi six. The latest engine on the dyno produces about 450 rear wheel horsepower normally aspirated and that guy is building a stroker version out to about 290 cu ins and will put out a shed load more hp. They take up so much less room than a V8 and are way lighter.

Nice idea but probably not practical or economical in this case, cost of importing the engine and trans (better get a few spare boxes haha) would probably outweigh the cost of dropping a 318 or 360 in. Good engines for sure, but probably much cheaper to build a small block in the US and you can have the same grunt with much better street manners.
Are they Chris's engines your talking about?
Is it a custom crank? I don't know if you would be able to get 290ci with offset grinding and boring, maybe honda size journals and thin bores?

I'd go with a 318/360 magnum swap, maybe even a turbo/blown slant if there's one already in the car.

 

[abodyjoe]

would appreciate people's thoughts on engine alternatives that don't make the car difficult to control or dangerous (e.g. no 440 block for me). Likely will put an automatic transmission with it so my wife will drive it on long trips.

nice stock 318 will do the job.

starting from scratch? if it were me i'd go modern hemi and be done with it.. use all the efi stuff too..

and for the record, a 440 will not make it "difficult to control" or "dangerous"...

 

[AJ/FormS]

Appreciate any input people have on the drive train related to balancing power with the reality that burn-outs, fish-tails and street racing are a thing of the past ... but we still sneak it in once-in-a-while !!!

360/5.9M, alloy heads, small-cam, hi-DCR/185psi
A500, 3.73s, 65=2080; or
A999LU, GVod, modest stall, 3.55s, 65=2240
narrowed 8.75, Trac-Loc, offset springs, lightweight slapper bars
period kidney-slot alloy wheels; 235/60-14s on the front ; 295/50-15s on the back
1.03bars, 1.125Hellwig, frame-ties, adjustable shocks
seats and belts to keep you behind the wheel, grab-bars
P/S, P/DB, re-engineered Proportioning, line-loc, small steering wheel.
slush-fund for all the tickets you will be getting

This is a clone of mine, except mine is a manual-trans
Tons of low-rpm power, the right gear at the right time, rubber almost anytime.

 

[Mopar Virgin]

Everyone ... Many thanks for the input and ideas. A couple people asked about budget, which will top out around $25K for the restoration work, net of what I paid for the body. The car arrived this morning and appears the body prep work will be minimal). This will be driven significant distances to events, errands and joy-riding. It came with a 225 Slant-6 from a '68 Dodge Dart. If an engine swap was made, are there any that would not require mount fabrication? Also found this YouTube video () of an optimized 225 that seems pretty amazing as well. Would need to assess costs of this option that would require a full tear down and rebuild of the engine + the weber carbs versus a new drive train as-is. Wanting to get the drive train determined se we can measure and make any needed changes before we take the body off to strip/prime and send to the paint shop. Additional comments welcome ... thanks!!

 

[diymirage]

LS swap it

With a ferd 9 inch rear end

 

[69cudaownr]

I believe you’re asking about the K frame for engine swap. The K frame for a /6, also works for the small block engines 318, 340, 360. Just need different engine mounts. I’m not sure about the 5.7 Hemi fitting the small block K frame, but that will be mentioned in a 3rd gen Hemi swap thread discussion.
Big block engines require a change in the K frame.

 

[furrystump]

Easiest would be any small block/904/8 3/4” rear. You could install a stock rebuild 318/340/360/Magnum and have a great cruiser. If in the future you want more power, you can build that small block to the point that you REALLY need to pay attention when driving it or you can get in trouble. Once it is a small block/904/8 3/4” it can be mild to wild.

 

[74Scooter]

For a cruiser you'll be putting miles on... if the /6 is not trashed rebuild and reuse it. If the /6 is is anchor iron.. get whatever SB LA is avail and affordable and call it done. I had a /6 in my 72 Dart Swinger and I loved it.

 

[OldmanRick]

All i can say is Welcome to Fabo.

Just too many choices/directions this could go for me to comment right now.

My main advice would be to take your time and look/research other Cuda's you like and make a plan from there. Spring is right around the corner, so maybe attend some Mopar get togethers in your area if available and talk to some people. Might give you a idea of where you want to go with the car. Good luck, and again, welcome to the best site on the net.

 

[harrisonm]

A slant 6 is not enough power, and a 440 is too much. There is a LOT in the middle. If you REALLY want a lot of streetable power, a 408 as suggested by @jazak5 would be hard to beat. Next step up would be a stock 318. That would give decent mileage and decent performance. Or you could easily warm up the 318 with a mild cam, good intake, headers and dual exhaust. That would give good performance and decent mileage. The next step up is a warmed over 360. They are easy to find, and 400 (+) HP is easy to get. Performance will be up, and mileage will be down. If you want to drive it a lot on "long trips", a fairly stock 318 with highway gears would be great, but it may not have the performance you want. The decision is yours. Only you can decide what level of performance you want, and what level of drivability, noise and mileage you want. So what do you want?????

 

[ir3333]

Yup... Best balance of performance, economy, handling and braking will definately be a smallblock.Pick the cheapest one available to you and warm it up a bit.
Now go have some fun.

 

[Topless69]

Easy way to do it: get the slant six running reliably while you sort out minor stuff to get it streetable and look around for a stock or modified running 318 & 904. If it’s stock, Breathe on it a bit (cam, intake, 4 bbl carb, headers, duals) and enjoy for a while until you get bored with the power levels. A mildly modded 318 is plenty for an A body, and doesn’t require more than the lightweight 904 and 7 1/4 rear, so you don’t have to do a ton of chassis, suspension, drivetrain and rear end work just to drive it.
JMO

 

[AJ/FormS]

will put an automatic transmission with it so my wife will drive it on long trips.

This will be driven significant distances to events, errands and joy-riding.

There's only three things wrong with a slanty cruiser; cruiser being 2.94/3.23 gears, namely; lack of power, lack of torque, and a really boring, characterless, snoring buzz out the tailpipe(s).
If you get stuck without an overdrive, and cruiser gears, you need a small block, any small-block. No you don't need one like mine, but if yur gonna rebuild whatever you get, it costs nothing more, besides alloy heads. But the very high cylinder pressure will save you money by driving further on every drop of gas. With my daily driver combo, I estimated that the alloy heads paid for themselves several times over in 125,000 miles, just in fuel savings, and in the meantime, 185psi is a real blast to drive.
Before you call me a slant-hater, I have had several, three of the early ones, and a low compression slug later one, that I immediately pumped the pressure up on. I only recently sold this last one, having driven it for most of 25 years.
The fact is; that normally aspirated, you have to really really love them to spend money on them, cuz any V8 similarly saddled with hiway gears will do everything better than the slanty except bore you to sleep.
With your budget, there is no way I would keep that 6-pot........

 

[Mopar Virgin]

A slant 6 is not enough power, and a 440 is too much. There is a LOT in the middle. If you REALLY want a lot of streetable power, a 408 as suggested by @jazak5 would be hard to beat. Next step up would be a stock 318. That would give decent mileage and decent performance. Or you could easily warm up the 318 with a mild cam, good intake, headers and dual exhaust. That would give good performance and decent mileage. The next step up is a warmed over 360. They are easy to find, and 400 (+) HP is easy to get. Performance will be up, and mileage will be down. If you want to drive it a lot on "long trips", a fairly stock 318 with highway gears would be great, but it may not have the performance you want. The decision is yours. Only you can decide what level of performance you want, and what level of drivability, noise and mileage you want. So what do you want?????

Appreciated the input and not sure if my attempted youtube video post to the group was visible to you. If not, would appreciate your thoughts on this /6 upgrade end-state versus the V8 route -- https://youtu.be/4zHxzHEs14k This seems like an interesting optimized 225 that appears pretty amazing as well. Would need to assess costs of this option that would require a full tear down and rebuild of the engine + the weber carbs versus a new drive train as-is.

 

[abodyjoe]

Appreciated the input and not sure if my attempted youtube video post to the group was visible to you. If not, would appreciate your thoughts on this /6 upgrade end-state versus the V8 route -- https://youtu.be/4zHxzHEs14k This seems like an interesting optimized 225 that appears pretty amazing as well. Would need to assess costs of this option that would require a full tear down and rebuild of the engine + the weber carbs versus a new drive train as-is.

cool little motor but 282hp and 291tq? ill bet there is a ton of money in that thing to get those numbers. mild V8 can easily surpass that snd probably cost half to build.

 

[Mopar Virgin]

Oh oh, You didn't give a budget. My thoughts would be a 5.7 Hemi drivetrain to an 8 3/4 rear, (you likely have a 7 1/4 rear in there now). Stock 8 3/4 rear can handle 275/ 40R17 which is a fair bit of wheel without customization. Make sure you have large bolt pattern axle in the 8 3/4 for better wheel options. Small bolt pattern wheels are scarce and expensive.

Budget is $25K for everything except the acquisition of the car (ie. body-off paint, front-end suspension, reupholster interior, replacement bucket seats, A/C, power steering, wheels/tires, misc.). I could cover another $5000 without facing a divorce. From what I'm reading from everyone since posting this, I'm gravitating away from sinking costs into hi-perf /6 upgrades and likely to go the 318 route to stick with the same K-bracket. Were you able to fit 275s into the rear without modifications?