cesar.r.burgos
Active Member
i was just wondering how much power can i really pull out of a 225 slant 6 in my 72 demon... where can i find parts for it and how much is it going to run realistically....
Slant 6 power?
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66aCUDA
/6 Racer
Slantsix.org is FULL of our beloved slant 6 info. 250 HP is a common figure.There are a number of vendors for speed parts. I represent one but explore ALL vendors and choose wisely.
Frank
Frank
Probably enuff to granade the thing !!
It depends; there are some normally-aspirated '6s running 11.50s in 2,300-pound car (that takes about 300 HP), while the turbocharged cars can run 127 mph in the middle 10s with about 440 HP.
These numbers are from an online calculator that is probably not the most accurate way to measure horsepower, but will get you some idea of those engines' output.
What exactly do you want to do,a comfortable street car or a street terror?
A Super Six from what I have read will do real good,but there are some members here use a 390 1bbl Holley with a 4 bbl intake from several places some can be reasonable in prices to high in prices. Check ebay or the classifieds here.
I'm right at the beginning stages of a long rod 225 buildup now. I think 250 HP from a naturally aspirated slant is a stretch........for a STREET driven slant, but it certainly can be done and then some. They just get really radical at that power level and above. I am giong to be perfectly happy with whatever mine ends up being. I project 200-220 HP. And that will be snappy in a 2650 pound 1963 dart with a 4 speed overdrive and 4.30 gears. Something fun to drive is what I am after. If it gets too radical, it will be fun to drive only for a short time....then it will become a chore.
SS will you let me know so I can follow along?
805moparkid
Slant and AFX Guy
SS put it very well... unless your building a race motor i wouldn't go anything over a 235 @ .050 cam and 9.3:1(regular gas)...
as for dollar for HP these can be very expensive unless you are choosy about how you spend your money or you boost it...
as sl6dan will point out clifford is a name to be careful around... i would only buy there intake if going for hot street or race... otherwise the offy will do fine...
I sure will. I suppose I should get a thread goin now because I have the block, pistons, and some of the head work done. I am using stock 318 1.74 and 1.50 valves. I finally found some 198 connecting rods at a price that didn't require me to hack out my left nut with a dull rusty knife. Thanks Frank!!!! So, I will be addin a thread pretty soon. Gotta get some pics first and I will get the thread up in a day or so. I'm stoked. It's gonna be fun.
805moparkid
Slant and AFX Guy
why did you go so big on the exhaust valve? 1.44 would be plenty...
The 302 cubic inch 1968 Chevy Z-28 has virtually the same per-cylinder displacement as a 225 /6. (225/6 = 37.5; 302/8 = 37.75.)
Chevrolet saw fit to put 1.6" exhaust valves in those motors, and we all know how those engines run.... Bigger valves USUALLY make more power.
805moparkid
Slant and AFX Guy
agreed but on you have to think of how much bigger of a port they were dealing with (and a 2.02 intake??)... also there is no reason to have that big because of compression, more in, less out...
stage V found by reducing the exhaust valve by i think .004" on there hemi heads they picked up like 5-7cfm through out the mid range and lost nothing on the top end...
so what i am getting at is yes bigger valves make more power but as a "rule" the exhasut should be 80% of the intake size... so 1.80/1.44 would be perfect... in theory...
and thanks bill! fun to go back and forth like this! learn this in the process!
Just stock 318 valves. I don't consider them that big. lol
How well do you think the heads will flow with the 318 valves?
Since I am planning on porting the head, running good headers and making a smart camshaft choice, probably pretty good.
I don't know what my hp is :-k all stock 170/ from the valve cover down :happy10:
I removed the breater and added a 93 Jeep breather to grab cool fresh air, 390 holley dp carb, Offy intake, split my exhaust 2'' to the tail shaft and 2 1/4 to a quite mufler, added mopars electronic ignition coil and plugs.
Cost :dontknow: but she runs a 11.30 1/8 mile now, 2.700 lb car so I am going to guess it has about 130 hp.
remember this is just 60 hp away from a 190hp 318.
Cool air, good spark, take the potato out of the exhaust helps these high reving 170/ move real good.. There is allot to be said about keeping 190 degree air out of your engine :happy10:
I sill need to spin my carb and get steal lines run to my carb, As you can see this is my daily driver that needs to be cleaned up, put she is getting there one step at a time
I removed the breater and added a 93 Jeep breather to grab cool fresh air, 390 holley dp carb, Offy intake, split my exhaust 2'' to the tail shaft and 2 1/4 to a quite mufler, added mopars electronic ignition coil and plugs.
Cost :dontknow: but she runs a 11.30 1/8 mile now, 2.700 lb car so I am going to guess it has about 130 hp.
remember this is just 60 hp away from a 190hp 318.
Cool air, good spark, take the potato out of the exhaust helps these high reving 170/ move real good.. There is allot to be said about keeping 190 degree air out of your engine :happy10:
I sill need to spin my carb and get steal lines run to my carb, As you can see this is my daily driver that needs to be cleaned up, put she is getting there one step at a time
Have you ever seen the exhaust port on a 327 small block Chevy head?
I'd be surprised if it's ANY bigger than a /6 exhaust port.
I don't think it is. The intake, yes, but they had 2.02" valves to feed...
cesar.r.burgos
Active Member
this last picture reminds me that i need to work on the tranny... well i want a just a nice ridding demon for now but ultimately i was a street terror .. mabey after i get a second car... im thinking about adding a turbo and keeping the psi low like at 6 psi like the slant six site said to for greater fuel economy... but i think my original question was more of a thought into the future.. oo and thanks for the input guys
805moparkid
Slant and AFX Guy
exactly.... if you cant get it in there dont worry about getting it out!
by making to big of an exhaust valve you can slow velocity and over scavenge causing and over rich condition that you could not tune out of it at certain rpms...
2 Darts
A-body Addicted
Big valves are nice, but! The 302/350 Chebby has a 4.00 bore, the /6 has 3.40.
Mopar recommends 1.70 intake and 1.44 exhaust for /6 hop-up. By comparison, stock is 1.50 intake and 1.36 exhaust. According to FABO members, larger valves don't realize their potential unless some mild porting is performed. The Mopar 6 Cylinder book has porting templates for the /6 in it.
How wild do you want to go?
[ame="http://www.youtube.com/watch?v=8d-qqeK0B-I"]YouTube - slant six[/ame]
Mopar recommends 1.70 intake and 1.44 exhaust for /6 hop-up. By comparison, stock is 1.50 intake and 1.36 exhaust. According to FABO members, larger valves don't realize their potential unless some mild porting is performed. The Mopar 6 Cylinder book has porting templates for the /6 in it.
How wild do you want to go?
[ame="http://www.youtube.com/watch?v=8d-qqeK0B-I"]YouTube - slant six[/ame]
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