Newer vs Older

-
O

opus65

Well-Known Member
Joined
Jun 3, 2012
Messages
77
Reaction score
13
Location
Indiana
Been looking into a slant six project for a while. Came across a middle 80's version at a good price. Would listen to opinions on whether later slants are better, worse, no difference compared to earlier versions. Is there a year/version that has more things going for it compared to other years of "Old Reliable".
Thanks
 
unless you can find an aluminum block, i'd say they are all the same
 
Be aware there is a transmission interchange issue between 67-and-earlier and 68-and-up. So if you already have a transmission in mind, stay in that year range. You can get an adapter for later engine/early transmission, but not the other way around.
 
Somewhere in mid ? 80's they went to hydraulic lifters, which is no big deal. I think the last slant came in a 88 pickup?? You will find some things like the super six (2 bbl) to be pretty common in , later 70's, also the exh man had ribbing starting in 70 something ?? that gave it better strength. Basically a slant is a slant IMHO.
 
I recommend this book: Chyrsler Performance Upgrades, 1999, Frank Adkins ISBN 1-884089-40-2

In there he lists the differences. From memory:
1) Aluminum block: early 60's I think? It had many issues.
2) 190 vs 225 (and was there a 170 too? Maybe I just made that up)
2) forged vs cast crank (they are not interchangeable) Changed in the late 60s?
3) transmission mating (they changed the flange or something) in the early 70s?
4) Hydrophilic lifters in the late 70's or early 80's?
 
170, 198 and 225. I assumed he was only interested in a 225, but maybe not...
 
The 67 and older have a smaller crank shaft register.Thus flywheel and torque converter snout sizes differ from the 68 and later.
Around 1976 they went to cast crankshaft and the block/crank is different.1980 was the last year for a solid cam.
Not sure but around 1974 the head changed and the spark plug tubes were no longer used.The new head is commonly called "Peanut Plug" because of the 5/8 hex plug.
 
Darter6 said:
The 67 and older have a smaller crank shaft register.Thus flywheel and torque converter snout sizes differ from the 68 and later.
Around 1976 they went to cast crankshaft and the block/crank is different.1980 was the last year for a solid cam.
Not sure but around 1974 the head changed and the spark plug tubes were no longer used.The new head is commonly called "Peanut Plug" because of the 5/8 hex plug.
Click to expand...
My 1980Volare had hydraulic lifters; my 77 had solids.
I thought 66 was the last year of the old-style convertor snout?
 
I have read the hydraulic lifter slants did not run as well and were problematic........no direct experience, so that may certainly not be the case.

@slantsixdan would be your best bet to answer this. Maybe he will chime in.
 
I should have stated that 1980 was a "transition" year as my 1980 Volare' had solids. Mopar was good at using what they had till they were gone. Either way it was about 'round that time.
 
Thanks or all the input so far. I think I am going to look up some stock camshaft numbers covering a range of years. See if cams were at all bumped up when lifters went hydraulic. If not, that may be the reason for Rusty's comment to have some truth behind it.
 
Ha! After looking at the puny cam numbers I decided to send mine to Oregon Cam for a regrind. Stock was .375 lift IIRC.

Mine's still mild but it's somewhere between stock 318 and 340 specs.
 
Main thing is IF you prefer the body styles in the late 70's, early 80's OR the earlier bodies. I have some of all and I see things I like in all of them. I doubt you see much difference in year slants in stock form. I have a 79 volare with a 2 bbl, the gear is the main factor.
 
barbee6043 said:
the gear is the main factor.
Click to expand...

What he said;
I know you didn't ask for this, but here are some examples;
get yourself an A999 and BIG gears, and save a boatload of cash and endless frustration.
The slant just can't cover all the bases, so choose one or two and call it done.
As a city car, you might want 3.73s and a 2400/2800TC to go with that 2.74-1.54-1.00-locup transmission. In first gear; this will far far FAR out perform just about anything you do to the engine if you keep the 2.73s back there, short of supercharging it. And quite possibly/very probably, thru most of second as well.
Here are the final drive,torque-multiplying, road gears, with tire correction;
First the 3.73s and A999 with 28's; 8.76-4.92-3.20, and
then the 2.73s and A904 with 26.5s; 6.05-3.59-2.47
First gear is Plus45%, second is Plus37%, top gear is Plus30%
Draw your own conclusions.
What's it gonna cost to build your engine to match those numbers?
barbee6043 said:
the gear is the main factor.
Click to expand...
3.73s will get you 60 mph @~4340 at the top of second gear,with tall-boy 28s.
The starter gear is 10.22, before tire correction.
28mph will be 1930 cruising in 2nd, and 3600 in first at WOT; Kapow!!.
Forget the cruiser gear; this is the sacrifice you have to make with a NA stock-slanty. If you gotta know; 65~2910......60~2685
If you do the math on stockers, and I'm gonna guess a little;
The 318@1850/904 with 2.73s, is putting down about 1200 ftlbs on the start line.
The 225@2800 /999 with 3.73s maybe 1800. Yur gonna need a "posi" And
The 225@1850/904/2.73s,about 700. If you hop it up with; more compression,a bigger cam, a 4bbl, and a free-flowing exhaust? still about 700, maybe 770tops,lol.
barbee6043 said:
the gear is the main factor.
Click to expand...

_________________
I built a similar combo in ~1978 with a 69 Barracuda 904/2800 mind you and a recently remanufactured chain-store-bought, stock spec, 225. And had a hoot of a time for around 3 years, until some younger kid (I was just 25 myself), made me an offer I couldn't refuse. It wasn't 340 fast obviously, but it was sure fun hearing those 6 cylinders screaming out the back, in two gears.
 
Last edited:
'I have read the hydraulic lifter slants did not run as well and were problematic........no direct experience, so that may certainly not be the case.

not to knock the old guy, as usual RR is spouting something he does not have really good info on,
hence what he says is just noise,,RR,, if you really don't know, maybe you should say you will,,, find out, get some experience, then post. Why blow smoke?

From a person that does know, I have a hydraulic 83 D150, engine- motor- chassis- all 100% gone through,
ran before and runs now,,,and runs strong
set up to be a low RPM tow vehicle,,runs great, no complaints. Hydraulic lifters and all.
Nice thing about slant hydraulic lifters, top oilers with plenty of preload range capability.
no here-say,, done it and did it and it works,
 
Last edited:
As to which is better IDK.
I have had a 65,a 69,a77, and an 80hydro; mostly stock slugs.
>The 65 was an oil-burning POS from day-one. I didn't have it long before I replaced it with a JY340. I bought that car in~73, so that slanty was 8 when I got it.
>The 69 was tired but ok when I got it in 75, I replaced with a store-bought unknown year remanufactured engine, about 3 years later.I sold it to a kid, car and all, after I drove it for about 2/3 Years. About 3 months later, I seen the kid, walking again. Seems the engine lost it's oil and it threw a rod. No he didn't blame me,lol. I think up to that time, he had wrecked every engine in every car he had had; three IIRC. Nice kid.
>The 77, I had custom built with more compression, and a slightly bigger SOLID cam, plus the SS setup.This 77 was rebuilt in 94, and still fires right up and burns no oil. I'm pretty sure it has over a quarter of a million miles on it. Still on the original chain and all-steel gears I think, as I don't recall ever replacing it. Hmmmmmmmmmmm, that's pretty good EH?
>The 80 didn't last long for me, the PO ran it pretty hard.
They were all "good".
 
Last edited:
My experiance has been the early forged crank solid lifter slants. However, I recently got a 84 D-100 with a hydraulic cam. I have no Idea how many miles are on the engine. All emission devices and "lean burn" have been removed, and a 2bbl carb added, along with a larger exhaust system. It does have some oil leaks, which I will address this fall/winter. It has the A-833od trans, and someone upgraded the rear to a 8 3/4 with 3.91SG. I towed my race car from Florida to Tenn, and back, two weeks ago. I was moderatly satisfied, with the way the truck ran. It could use a little more power, as I needed to down shift on the long grades, and go to 2nd gear on some of the steeper hills. I never did excede 3500 rpm. Cruising on the highway was approx 65 mph, and 2200 rpm. Biggest problem I had, was starting from a stop, on a fairly steep hill. The small clutch did not want to fully grab, and would slip pretty bad.
 
My experience with later slants is like Charrlie_S there. I had a '88 I believe, maybe last yr for the slant, 4 spd 833 OD no idea the gears this was bout '92, a super clean nice truck. It had no emissions stuff, maybe taken off or whatever. I would pull the trailer with a b body down the highways probably 60 tops, but the hard part was getting going. Clutch was weak for the load I was trying to get rolling. I drove it maybe 6 mo. and picked up another 3/4 t.
I personally would not be afraid of any slant.
I have heard people argue the virtue of forged vs cast canks eeven in big blocks, and have seen many racers run the cast crank hard with no issues. I hear same discussion with the crank in slants, but their bearings are size of the 426 hemi. Hydraulic lifter engines, I have no idea.
 
RustyRatRod said:
I have read the hydraulic lifter slants did not run as well and were problematic........no direct experience, so that may certainly not be the case.

@slantsixdan would be your best bet to answer this. Maybe he will chime in.
Click to expand...

That would be due to the Lean Burn system that was ran on the hydraulic lifter slants but the actual engine itself was fine. Remove it for a conventional setup and there's nothing wrong with the engine at all.
 
I was told by a member here that ~1974 were the strongest blocks and still had a forged crankshaft. I haven't heard of wild cams for the 1980's hydraulic lifter engines. I recall posts on converting them to solid lifters, and fairly easy. It is harder to go to hydraulic. The later (~1980's) heads dropped the spark plug tubes, and I think went to smaller body plugs. Those are termed "peanut heads". The main disadvantage is that you must remove the head to change the lifters. Also, the tubes make it more like a Hemi engine for bragging rights. Indeed, some parts on the crankshaft (oil seals, ...) interchange with the 426 Hemi. SlantSixDan was an expert, but he has mostly left the forum (no slant car anymore). You can find much more tuner info at www.slantsix.org.
 
All the same better heads were from 68 and up, later motors are almost the same only difference is how low the piston is in the hole giving the engine lower compression ratio, earlier motors were less in the hole than later but either way, mill the head is a must on these engines. Cast crank motors were a little lighter and came with the peanut heads.
 
You must log in or register to reply here.
-

Back
Top