Slant Six Build Ideas

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John Martin

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Sorry to start a new thread again, but I had to start over and ask my question again due to getting a rude answer the first time.

I want to build an economy slant six that is reliable and can be driven every day. The build will start with a 1972 225 slant six. The car it is going into has air conditioning and power steering.

My goals are to make up the power used to drive the accessories and to get about 20mpg. Car will be used mostly around town and I would like to use 3.23 gears. I was also thinking of installing a higher stall torque converter as well.

I am planning on a Melling oil pump, flow-kooler water pump, electronic ignition. I would like to keep it outwardly stock looking.

I would like to swap a camshaft. I was looking at AussieSpeed’s Evil Stick, Comp Cams, and Erson RV10.


Thanks in advance
 
One interesting thing you could do that would improve fuel economy and make it faster than stock is to turbo it. As long as you do it right; i.e. lower compression than usual, gapped rings, balanced internals, you could have a fun, reliable engine. Also, you could hide the turbo down by the oil pan and just run a secretive charge tube back up into that emissions tube that goes into the snorkel. In order to keep it stock looking.
or just make a high compression slant and efi.
 
One interesting thing you could do that would improve fuel economy and make it faster than stock is to turbo it. As long as you do it right; i.e. lower compression than usual, gapped rings, balanced internals, you could have a fun, reliable engine. Also, you could hide the turbo down by the oil pan and just run a secretive charge tube back up into that emissions tube that goes into the snorkel.

Im not keeping the car, I’m giving it to my parents when it’s done. They wouldn’t know what to do with a turbo.
 
Oh, then you could just rebuild it and keep everything stock and just get a Holley EFI 2 barrel that just sits underneath the air cleaner lid.
Its not that hard to set up and the only thing you need to do is drive it around for about 50 miles to make the EFI learn. That makes it so that there is not cold or hot starting problems, no pumping the pedal to start, all the old car things that make them harder to own.
 
A Oregon cams 2106, Super 6 2 barrel and deck the block ~0.060” to get around 8.5:1 and it will do anything a modern daily driver will do and more.
 
Oh, then you could just rebuild it and keep everything stock and just get a Holley EFI 2 barrel that just sits underneath the air cleaner lid.
Its not that hard to set up and the only thing you need to do is drive it around for about 50 miles to make the EFI learn. That makes it so that there is not cold or hot starting problems, no pumping the pedal to start, all the old car things that make them harder to own.

Carburetors are not a big deal. Keeping a Holley 1920 on it to make it serviceable. Nothing exotic or unusual.
 
Sorry to start a new thread again, but I had to start over and ask my question again due to getting a rude answer the first time.

I want to build an economy slant six that is reliable and can be driven every day. The build will start with a 1972 225 slant six. The car it is going into has air conditioning and power steering.

My goals are to make up the power used to drive the accessories and to get about 20mpg. Car will be used mostly around town and I would like to use 3.23 gears. I was also thinking of installing a higher stall torque converter as well.

I am planning on a Melling oil pump, flow-kooler water pump, electronic ignition. I would like to keep it outwardly stock looking.

I would like to swap a camshaft. I was looking at AussieSpeed’s Evil Stick, Comp Cams, and Erson RV10.


Thanks in advance

Then just build a stock one. what kind of returns do you think you'll see from the overpriced Aussie camshaft with the snappy name? Without several other upgrades, you'll likely be wasting your money.
 
As mentioned, you want to deck the block considerably to get halfway decent compression

Find a nice intake and hog out the exhaust manifold Ala RRR
 
As mentioned, you want to deck the block considerably to get halfway decent compression

Find a nice intake and hog out the exhaust manifold Ala RRR

I will be getting the head reworked which is a painful $1200.

I also plan on cleaning up the manifolds for sure. I will try to gasket match.

I would like to get maybe 9.0 to 1 or 9.5 to 1 compression.
 
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I will be getting the head reworked which is a painful $1200.

I also plan on cleaning up the manifolds for sure. I will try to gasket match.

I would like to get maybe 9.0 to 1 or 9.5 to 1 compression.

Don't forget the tail end of the exhaust manifold
You can open that up quite a bit and run 2.25 inch pipe out
 
Don't forget the tail end of the exhaust manifold
You can open that up quite a bit and run 2.25 inch pipe out

For sure, but I got burned by Accurate Exhaust. Accurate gave me a hard time about their 1 7/8” standard tail pipe. I’m trying a TTI 2.5” system this time.
 
I have no experience with either brand of exhaust that you mentioned, but I have done lots of exhaust using pre bent pipes over the years in my work. Usually Walker or Maremont.
It was not at all uncommon for the tail pipe to be a size smaller than the extension pipe going into the inlet of the muffler.
 
I have no experience with either brand of exhaust that you mentioned, but I have done lots of exhaust using pre bent pipes over the years in my work. Usually Walker or Maremont.
It was not at all uncommon for the tail pipe to be a size smaller than the extension pipe going into the inlet of the muffler.

The size of the exhaust is not it issue with Accurate it is the figment since they claim to use NOS parts to make their reproductions. They berated me saying that an unrestored car that has an original exhaust is wrong and that they are the basically the ultimate authority on exhausts. They can go f themselves.
 
I have a similar thread about building up a slant, too. As I have had time I have gone back and read many of the threads before the current page, I think I'm back to about page 60, and when I go back in the archives even getting back to where I left off, I see some that I thought I might have missed,seems like I've been thru at least 3 cycles of the same questions that rotate around.
One thing that seems to come up that can be agreed on is the need to shave the block and head to get the compression up to where the service manuals have claimed that it always been all along (your engine is most likely NOT there) for the biggest bang for the buck upgrade even on the mildest of overhauls. What cam or whether or not to put bigger valves, what size of carb to run, what gear to run out back, whether a daily driver or a race car everyone says to bump up the compression
 
I have a similar thread about building up a slant, too. As I have had time I have gone back and read many of the threads before the current page, I think I'm back to about page 60, and when I go back in the archives even getting back to where I left off, I see some that I thought I might have missed,seems like I've been thru at least 3 cycles of the same questions that rotate around.
One thing that seems to come up that can be agreed on is the need to shave the block and head to get the compression up to where the service manuals have claimed that it always been all along (your engine is most likely NOT there) for the biggest bang for the buck upgrade even on the mildest of overhauls. What cam or whether or not to put bigger valves, what size of carb to run, what gear to run out back, whether a daily driver or a race car everyone says to bump up the compression

I would like to run a 2200 stall torque converter and do a 7 1/4 with a 3.23 Sure-Grip. I am keeping the 904.
 
think you need to decide how and how far your engine will be built up and then decide on a converter, building an engine to match a given converter seems backwards. That said, I don't think 2200 is much above the factory "hi stall" version.
 
think you need to decide how and how far your engine will be built up and then decide on a converter, building an engine to match a given converter seems backwards. That said, I don't think 2200 is much above the factory "hi stall" version.
I never said I was building the engine to the converter. I do realize that the way I’m building the engine will not be much over the original 110hp it was rated at. So with that being said, a high stall converter will take too much power to turn, before anything gets moving.
 
So with that being said, a high stall converter will take too much power to turn, before anything gets moving.


i never heard of a high stall taking more power to turn...in fact, i thought they turn like a regular convertor and engage the transmission at a later point, where there actually is power available
 
i never heard of a high stall taking more power to turn...in fact, i thought they turn like a regular convertor and engage the transmission at a later point, where there actually is power available
I will have to find the article again and reread it. I glazed over a lot and I have a lot of personal things going on. Yesterday was busy.
 
I will have to find the article again and reread it. I glazed over a lot and I have a lot of personal things going on. Yesterday was busy.

no rush, im just making conversation

(and i may very well be wrong)
 
The size of the exhaust is not it issue with Accurate it is the figment since they claim to use NOS parts to make their reproductions. They berated me saying that an unrestored car that has an original exhaust is wrong and that they are the basically the ultimate authority on exhausts. They can go f themselves.

That's similar to Hughes Engines attitude. Also similar to my response to them as well.

The exhaust manifold I just put on this engine is opened all the way up to 2.5" outlet.

MANIFOLDS ON.jpg
 
I would like to run a 2200 stall torque converter and do a 7 1/4 with a 3.23 Sure-Grip. I am keeping the 904.
John, unless you already have a good 7 1/4 sg (with good clutches) I would not use it. I searched for a few yrs for 7 1/4 parts to build my latest one. Parts are very hard to find, and not inexpensive. I have about $500 in parts in mine 3.91 SG. I ran those rears for many years, with good results, but really not viable choice, today.
 
John, unless you already have a good 7 1/4 sg (with good clutches) I would not use it. I searched for a few yrs for 7 1/4 parts to build my latest one. Parts are very hard to find, and not inexpensive. I have about $500 in parts in mine 3.91 SG. I ran those rears for many years, with good results, but really not viable choice, today.

that is about what i got into my 8 3/4 SG...of course, that was a few years ago

but in this day and age, the affordable choice is converting a 8.8 out of an exploder
 
Ask 10 guys opinions and you'll get 20 answers.

So here goes. You say you want economy and it's for your parents. No use spending money on fancy stuff like sure grip and hi stall converter. My parents and millions of other parents drove these cars forever bone stock. You can improve on it though.

Charlie said a long time ago that there is no down side to increasing compression and it helps economy and power. So I milled my 225 head .080. (I wanted .100 but my machinist was against it so we compromised) You give some back because composite head gaskets are twice as thick as the original .020 steel.
100% rebuild, bored and honed professionally. I'd have to look but the machine work was 500 something.
Forged crank was checked and polished, no cutting.
Silv-o-lite pistons, King bearings, Hastings moly rings. I bought a kit and picked components eith my machinist.
Gave Oregon Cam a call, told them my intended use and specs and he recommended 2 grinds using my stock blank. I went with the milder because this is a driver afterall. Cost with shipping was 120.
Head rebuilt and had him put hardened exhaust seats in. (He was against that too) I pocket ported and gasket matched myself. Cost for the head work was 400 something.
He refaced my solid lifter rockers for $6 each. (He had a jig)
Installed Rolmaster roller timing chain and degreed cam.
Did a little intake porting and enlarged exhaust outlet before RRR made such a big deal about it.
Rebuilt original BBS Carter with a good kit from Daytona Carb.
Replaced the distributor drive gear myself and set endplay to specs using shims.
Checked oil pump to FSM specs and reused because of known drive gear problems. Also added a distributor drive gear oil squirter for same reason.
Installed brand new larger exhaust system. Going bigger in the future but this was a lucky swap meet find for only $40.
Painted engine red because 64 Valiants had red engines.

Close to 10,000 miles on rebuild finished 4 years ago. Have not changed plugs or points (dwell is still good) Driving to Carlisle I get 23-24 mpg at 65-70 mph on 87 octane. 3 speed manual and 3.23 7-1/4.
It scorched the quarter mile at 18.51

Edited: my head was milled NOT the block
 
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