Slant factory performance

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Jonnylightening

Jonnylightening

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Just recently picked up a running slant from a 67 barracuda for $75. Going to be keeping the bottom end together. As far as bolt on factory parts what would I look for as far as what makes the most power if any? Which heads flow best, exhaust manifold, intake(probably super six)?
 
Mill the head to get about 9.0 compression, clean up the pockets, get a great valve job, Viton valve seals, cam in the 260 - 268 duration range, valve springs to match the cam, double roller timing set, 2 1/4 exhaust pipe, low restriction muffler, OEM 2 barrel intake and carb, electronic distributor with a quick curve, good rings, round and straight bores.
 
First thing to keep in mind. The 1960-1967 slant six (and small block) had a smaller pilot hole in the back of the crank, than the 68 and newer engines. Therefore, you cannot use this engine in front of a 1968 or newer automatic transmission, without a special/custom torque converter.
Head flow and exhaust manifold does not really make enough difference to be concerned about. However, while the head is off the engine, I would have it milled to raise the compression ratio, and get a quality valve job done. Over size valves and some porting will help, but without doing other work, such as a cam upgrade and/or more carburation, I don't think it is worth the money, unless the valves need replaceing, anyway. Factory manifold would be a super six (2bbl) (but they are getting pricey) aluminum if possible. Low restriction exhaust system on the vehicle.
 
Just like any engine they are a basic air pump. The more movement of air in and out the more power they produce.
Just as Charrlie S stated milling the head to raise compression,good valve job and up grade the springs then intake,carb and exhaust mods.
You will be surprised at the difference.I advise a leakdown test to see if the piston rings are sealing good.If so go for it.
Your plan is just what I did to my 67 Dart. Milled the head .100, 340 valve springs, 4 bbl intake, 500 cfm AFB,headers and a 2 1/2'' single exhaust to the back bumper. The stock 225 cam was still in use.2.76 rear gears.In stock form top speed was barely 90 mph.
After the mods it would top out at a easy 115 mph.
 
If staying with the stock cam, the stock springs should be fine, as long as they are set at the proper height when doing the valve job. An inexpensive upgrade are the stock 318 springs (which are the same as replacement slant springs), or stock 340 springs.
 
The cylinder head underwent a few revisions through the years. Leaving OUT the 67 and prior heads, I think the general consensus is that the 68-74? head is best. The 75-81 head had another revision that eliminated the drool tubes, but also makes it impossible to get the lifters out without removing the head.

To me, the biggest two shortcomings the slant 6 had was the fact that the cylinder head, although revised a few times, was never redesigned with the larger 225 engine in mind. It retained the same small ports and valves that was designed for the 170. That's easily overcome with porting and adding bigger valves.

The second shortcoming is that there was no real "HP" exhaust offered. There've been reports of exhaust manifolds with a larger outlet, but even on the Super Six (factory 2 barrel engines) most of them still retained exhaust manifolds with the smaller 1 7/8 outlet, although Chrysler did add a 2 1/4 exhaust PIPE on the Super Six, the exhaust still had to come through that tiny outlet, so it was really a moot point. On mine, I had a friend port my exhaust manifold and also open the outlet up to 2.5".....because he's a miracle worker with a die grinder and I just SUCK. I added the TTI 2.5" full HP single exhaust and that really helped a lot.

I have a small Holley style (Quick Fuel) 450 vacuum secondary four barrel on an Offenhauser four barrel intake. I'm fixin to upgrade THAT to a Quick Fuel 650 double pumper. Bottom end is stone stock with the only two exceptions being a large solid lifter camshaft and a high quality JP (Rollmaster) timing set. The head is stock except it's been heavily milled. Compression is 10.2, and it has valve springs to match the camshaft. It runs surprisingly well for having basically a stock head. But still, it'll never be a V8 and that's cool with me. Coupled with my car's light curb weight (about 2600 pounds) it's very snappy and a lot of fun to drive. Plus everyone who sees it's "just a six" is always blown away. It's been the most fun car I've ever owned and I've owned a lot of them.

The slant 6 can be a lot of fun, as long as you know it'll never be a V8 and you like having something different. There's always EFI, nitrous, turbocharging and supercharging, but I prefer naturally aspirated with a good old carburetor. That's just what I like.
 
Yup. As with anything you will need to check retainer to guide clearance at max lift. That's a fairly stout single spring, so it should handle most anything you would want to run as for camshaft.
 
Screw all that work.

BOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOST

ebay turbo, blow through carb, win races get chicks.
 
jos51700 said:
Screw all that work.

BOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOST

ebay turbo, blow through carb, win races get chicks.
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Actually that is my plans! I have a 2bbl intake that I'm dead set on using. I have a hard on for the holley 2300 sniper so I'm planning on going that route. I was more less wanting to do a low budget build with as much factor bolt on parts....stuff I can find in a salvage yard.
 
There's always supercharging, too. Not cheap, though.

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Good ol' Allpar. Even before it was sold to the moneygrubbing greedbags at VerticalScope who don't know or care jack ѕhit about cars—Mopar or otherwise—because their only interest is clicks on ads, Allpar had a terrible signal:noise ratio, because anyone could write for it and there was no fact-checking or editing unless someone would write in and squawk about errors, then that squawk would get put up in a sort of guy-1-sez-ABC-but-guy-2-sez-XYZ manner. There was some good stuff on there, but it was impossible to tell it apart from the rubbish and nonsense unless you already knew, which kind of defeats the point. Still is, only now more so because VerticalScope.
 
Rug_Trucker said:
Was this your project? I am questioning how the heck the author got 44mpg out of a slant!
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Let's start in the middle: 225, 2-bbl, 0.030" clean-up bore, 0.100" shaved of the ported head, stock size valves, Comp Cams 252M, stock 2.76 rear, and OD 4-speed. I played around with screen under the carb and got a best of 29 MPG. I then bought a (now defunct) product called the Power Plate. It was a 1" aluminum spacer with coolant jackets running through it (had to tap into the heater hoses for that). Each throttle bore had an 8* tapered cone with 20-pitch screw threads. The cones protruded about 1/2" - 3/4" into the intake plenum. With the Power Plate, it was like I pulled the /6 & dropped in a 360 2-bbl! The power was simply amazing! Oh, and I was able to squeeze a 44.7 MPG 55 MPH run out of it. It would deliver high 30's normal driving.
powerplate1.jpg


powerplate2.jpg
 
mpgmike said:
Let's start in the middle: 225, 2-bbl, 0.030" clean-up bore, 0.100" shaved of the ported head, stock size valves, Comp Cams 252M, stock 2.76 rear, and OD 4-speed. I played around with screen under the carb and got a best of 29 MPG. I then bought a (now defunct) product called the Power Plate. It was a 1" aluminum spacer with coolant jackets running through it (had to tap into the heater hoses for that). Each throttle bore had an 8* tapered cone with 20-pitch screw threads. The cones protruded about 1/2" - 3/4" into the intake plenum. With the Power Plate, it was like I pulled the /6 & dropped in a 360 2-bbl! The power was simply amazing! Oh, and I was able to squeeze a 44.7 MPG 55 MPH run out of it. It would deliver high 30's normal driving.
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You should of replaced your regular ol' boring ol' normal ol' smelly ol' spark plugs with amazing new Fire Injectors™, then you would of topped 50 mpg around town uphill in the snow, easy, and your highway mileage would be so good you'd actually find yourself with progressively more gasoline in your tank as you drove along—no word of a lie! Those Power Plates were amazing while they lasted; Big Oil bought the company out and shelved the product, right next to the 100-, 200-, 300-, and 400-mpg carburetors.
 
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slantsixdan said:
You should of replaced your regular ol' boring ol' normal ol' spark plugs with amazing new Fire Injectors™, then you would of topped 50 mpg around town uphill in the snow, easy, and your highway mileage would be so good you'd actually find yourself with progressively more gasoline in your tank as you drove along—no word of a lie! Those Power Plates were amazing while they lasted; Big Oil bought the company out and shelved the product, right next to the 100-, 200-, 300-, and 400-mpg carburetors.
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:rofl:
 
No, Dan, the Power Plates were melted down for scrap metal around 2000 because of lack of sales. Carburetors were becoming a thing of the past (at least for daily drivers) and the owner of the company just threw in the towel. Those are the real world results I got, that's my story, and I'm sticking to it.

As a side note, I spent a couple years pondering how the Power Plate concept could be adapted to newer port fuel injected engines. This birthed the Powre Lynz concept, where the screw threads were ground right into the intake ports. There are numerous other people that claim fantastic fuel economy gains with the Powre Lynz; just do a search.
powrelynz1.jpg
 
mpgmike said:
There are numerous other people that claim fantastic fuel economy gains
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There are numerous people who claim a lot of things.

Those 200-300-900mpg carburetor books you could order from a classified ad in the back of Popular Mechanics magazine were full of earnest testimonials, many of them dolled up all science-like with words like 'data' and 'findings'.

And don't let's forget about that humble dirt-farmer in India with the gradeschool education who, by the smoky yellow light of the cow-poo fire in his hut, figured out the secret magic secret to massively increased power and fuel economy by secretly carving secret grooves into the cylinder head (Shhh, it's a secret). Numerous people claim it works. No, it doesn't, not even a little bit, but the human mind just loves to latch onto myths and fairytales and conspeercy theories. We want to believe the truth is out there. We crave that feeling like we hold knowledge other people don't have. Makes us feel all special and powerful-like.

Hey, anyone else remember the Torque Plus™ fiasco? The one where Roland Osborne (Chief Editor and Preacher of Chrysler Power magamazine) ran articles trumpeting a big bunch of giant benefits to intake gaskets with screens across the ports? Giant increases in power and fuel economy; race-only cams now idled smooth as glass on pump gas, and no more waxy buildup on no-wax floors or spots on your glassware with amazing new Torque Plus™…and it turned out—fasten yer seatbelt—to be a big ol' pile of lies and nonsense (no duh, rilly?).

Mike, this is not the first amazing super-secret widget you've bandwagonned. Remember those "Powre-Valvez" you were hawking 16 years ago? Same big steaming pile of imaginary benefits, but the only 'data' the maker/inventor/chief cook and bottlewasher would provide was a little chart of LOLworthy numbers, claimed to be from a test on a Chev 327 motor. Same cold, hard reality, though, and—amaze!—that company folded, too. Musta been because um intake valves were becoming a thing of the past…er…um um…the owner threw in the towel and…um…HEY! LOOK OVER THERE!

Here in this universe, there's stuff that happens and stuff that don't. When it looks like stuff that don't be happening do be happening, it's usually because whoever says so doesn't actually understand what he thinks he sees. Or because he has a p'ticular intere$t in people believing he sees what he says he sees. Or because he's bound 'n' determined to see what he wants to see, in accord with his sincerely-held religious beefs.

Cool story, tho. You go on and stick to it all you want.

SunLight_Todd-Marsha-Sob.jpg
 
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slantsixdan said:
There are numerous people who claim a lot of things.

Those 200-300-900mpg carburetor books you could order from a classified ad in the back of Popular Mechanics magazine were full of earnest testimonials, many of them dolled up all science-like with words like 'data' and 'findings'.

And don't let's forget about that humble dirt-farmer in India with the gradeschool education who, by the smoky yellow light of the cow-poo fire in his hut, figured out the secret magic secret to massively increased power and fuel economy by secretly carving secret grooves into the cylinder head (Shhh, it's a secret). Numerous people claim it works. No, it doesn't, not even a little bit, but the human mind just loves to latch onto myths and fairytales and conspeercy theories. We want to believe the truth is out there. We crave that feeling like we hold special knowledge other people don't have. Makes us feel all special and powerful-like.

Hey, anyone else remember the Torque Plus™ fiasco? The one where Roland Osborne (Chief Editor and Preacher of Chrysler Power magamazine) ran articles trumpeting a big bunch of giant benefits to intake gaskets with screens across the ports? Giant increases in power and fuel economy; race-only cams now idled smooth as glass on pump gas, and no more waxy buildup on no-wax floors or spots on your glassware with amazing new Torque Plus™…and it turned out—fasten yer seatbelt—to be a big ol' pile of lies and nonsense (no duh, rilly?).

Mike, this is not the first amazing super-secret widget you've bandwagonned. Remember those "Powre-Valvez" you were hawking 16 years ago? Same big steaming pile of imaginary benefits, but the only 'data' the maker/inventor/chief cook and bottlewasher would provide was a little chart of LOLworthy numbers, claimed to be from a test on a Chev 327 motor. Same cold, hard reality, though, and—amaze!—that company folded, too. Musta been because um intake valves were becoming a thing of the past…er…um um…the owner threw in the towel and…um…HEY! LOOK OVER THERE!

Here in this universe, there's stuff that happens and stuff that don't. When it looks like stuff that don't be happening do be happening, it's usually not.

You go on and stick to your story all you want, tho.

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:rofl: :rofl: :rofl: :rofl: :rofl: :rofl:
 
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