pishta
I know I'm right....
A sticky Nitto/DOT drag tire is the easiest way but they dont last.
Usable power for the street?
- Thread starter ValleyRat
- Start date
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Yes and No
Engines that make high lbs-ft like 1.35-1.45:1 use lots Cr head flow big cams carb etc... Aka higher rpm.
What you generally want in the street is a strong hp curve from idle to 5000, 5500 max and since rpm is fixed an increase in torque in that range is the only way to increase hp in a NA engine and that's gonna be mainly done by displacement. Larger the engine more hp can be made at those rpms.
As for power needed most are happy somewhere in between 250-350 hp and a Hp:Cid ratio of
.08-1:1. Also gearing a 350 hp 440 is gonna need about a full ratio less than a 350hp 360 and 2 ratios than a 350hp 273 to have similar performance.
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Force of habit... always swap out lifters with new cam.
Rat Bastid
Dunamis Metron
Double adjustable shocks, which you should have regardless of what size your tires are.
Assassin bars. They bolt up, are fairly cheap and are much more adjustable than a Caltrac bar.
Then you spend some time tuning what you have.
Rollers are transferred over easy enough.
It depends on where your street is. It's easy to beat too much torque on the street from start through the 1/4 mile. 
A couple of south Georgia fat women in the trunk.
@RustyRatRod will they work better dead or alive??? 
Rat Bastid
Dunamis Metron
justinp61
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It depends on where your street is. It's easy to beat too much torque on the street from start through the 1/4 mile.
I chuckle when I read comments like this.
Naw they need to be alive. When they dry out, they lighten up. If they're still alive they still eat cupcakes and fatten up some more.
This is a classic example of knowing what one wants.
Too many think they want the horsepower, when what they really are talking about is the street power.
Yea I made that up to get the point across.
And a dyno can only hint at the torque and power at street rpms.
Too many think they want the horsepower, when what they really are talking about is the street power.
Yea I made that up to get the point across.
And a dyno can only hint at the torque and power at street rpms.
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thesiren74
Well-Known Member
You're weird..lol just kidding
DionR
Well-Known Member
I've got pretty much that exact motor (the before curve) and I want the after curve. Bad. Motor just feels slow. Fun enough around town when just driving it, but when I get on it (like passing on the highway), just doesn't feel like there is much there. Nice thing is, it shouldn't give up anything down low, but make a bunch more up top. Win-win.
Oldiron440
Well-Known Member
Thank you, thank you very much!
Ditto here. The engine is in very good health though!
A ‘00 - 5.9, RPM, 750 Edelbrock, 1-3/4 Super Comps-2-1/2 exhaust, MP chrome box, nice driver, dragging its *** after 4500. DOA @ 5K.
I’d like a similar cam to what Rich Holdner used in duration, but not the wide 114 LSA.
DionR
Well-Known Member
I'm putting in a Bullet regrind. 262/267 with 0.517/.520 lift. Pretty similar, just a bit less duration but more lift and 111 LSA.
Nice. I have noted the lack of cams around today. I was thinking of calling up Hughes.
Dale Davies
Well-Known Member
The 273 would be more original for that car. A tighter LCA cam with high lift would be the answer. Use David Vizard's formula for determining LCA.
LCA = 128 - (CID/#cylinders/[valve diameter × .91]). There are some "factors" that can be applied to tune the LCA like CR. Watch his Powertek 10 videos on Youtube or get a copy of his How to Build HP book.
Physically the external dimensions of the 360 are pretty much the same, so use what is available and easily attainable for you. Depends on your street definition. A search in parts books and comparing dimensions can provide slightly larger valves to aid low lift flow. At less than 0.350" lift (give or take) the valve curtain area is the flow limiter. This is the seat outer diameter (head dia x .91) x pie x lift. Above that the port becomes the limiting factor. So for a mild performance build, a bigger intake valve is a benefit. When the exhaust valve opens there is still 70PSI to 100PSI left in the cylinder, that pushes supersonic exhaust out past the valve. So this is not as critical.
For the 1966 289 in my 1940 Ford, I am installing the Chevy LS 1.9I, 1.55E valves. Stem length is about the same. Guys have been installing the 1.94 Chevy valves for years. The LS use a 8mm stem instead of the 11/32" small block Ford and Chevy size. My heads had beenn done once and the guides knurled. The machinist will be putting 5/16" guides in and hone to the 8mm. This way he can fine tune the stem clearance. The older 289 heads had a spring installed height of 1.64" while newer are in the 1.8". Mod motors use a spring with the right installed height. TFS sells PAC springs with the 1.64" installed height and good for 0.550" lift. Just need the retainers that fit the 8mm stems and the top of the beehive valves.
Seems the newer Hemis use a small dia stem also.
LCA = 128 - (CID/#cylinders/[valve diameter × .91]). There are some "factors" that can be applied to tune the LCA like CR. Watch his Powertek 10 videos on Youtube or get a copy of his How to Build HP book.
Physically the external dimensions of the 360 are pretty much the same, so use what is available and easily attainable for you. Depends on your street definition. A search in parts books and comparing dimensions can provide slightly larger valves to aid low lift flow. At less than 0.350" lift (give or take) the valve curtain area is the flow limiter. This is the seat outer diameter (head dia x .91) x pie x lift. Above that the port becomes the limiting factor. So for a mild performance build, a bigger intake valve is a benefit. When the exhaust valve opens there is still 70PSI to 100PSI left in the cylinder, that pushes supersonic exhaust out past the valve. So this is not as critical.
For the 1966 289 in my 1940 Ford, I am installing the Chevy LS 1.9I, 1.55E valves. Stem length is about the same. Guys have been installing the 1.94 Chevy valves for years. The LS use a 8mm stem instead of the 11/32" small block Ford and Chevy size. My heads had beenn done once and the guides knurled. The machinist will be putting 5/16" guides in and hone to the 8mm. This way he can fine tune the stem clearance. The older 289 heads had a spring installed height of 1.64" while newer are in the 1.8". Mod motors use a spring with the right installed height. TFS sells PAC springs with the 1.64" installed height and good for 0.550" lift. Just need the retainers that fit the 8mm stems and the top of the beehive valves.
Seems the newer Hemis use a small dia stem also.
Can you work this out for the various small block displacements? 273, 318, 340, 360?
Rat Bastid
Dunamis Metron
I can do the math but I don’t remember what the 273 had for an intake valve size.
Dale Davies
Well-Known Member
Rat Bastid
Dunamis Metron
273-106.9326 with a 1.78 valve
318-103.4599 with a 1.78 valve
340-104.8796 with a 2.02 valve
360-101.6965 with a 1.88 valve
408-100.7280 with a 2.055 valve
I always round down and make sure I have enough duration to carry the RPM I want.
You can’t use these numbers if you want a flat curve after peak HP. You have to open the LSA up for that.
318-103.4599 with a 1.78 valve
340-104.8796 with a 2.02 valve
360-101.6965 with a 1.88 valve
408-100.7280 with a 2.055 valve
I always round down and make sure I have enough duration to carry the RPM I want.
You can’t use these numbers if you want a flat curve after peak HP. You have to open the LSA up for that.
Thanks. I tried doing the math while on a short break from working on the truck. I didn’t come up with numbers that made sense so I did something wrong. So, frustrated & hot, I just left it to do some parts gathering.
Rounding up-ish…
A 273 will use a 106.9326 with a 1.78 valve - 107
A 318 will use a 103.4599 with a 1.78 valve - 103/104
A 340 will use a 104.8796 with a 2.02 valve - 104
A 360 will use a 101.6965 with a 1.88 valve - 101/102
A 408 will use a 100.7280 with a 2.055 valve - 100
Dale Davies
Well-Known Member
Yes. For a rebuild I use + 0.030 for the bores. So a 273 at 3.66" comes to 106.5. Anything bigger in the valve starts to shroud the intake. I would say a 107LCA would give the most torque. I think the formula for my 289 came out to 107. I have a cam from my 351 ground with 109 LCA I am going to use. DV says a cople of degrees will not do much harm, but going to 112 or 114 will drop peak torque and flatten the curve a lot.
For a 318 1.78 looks like 103.1°. Seems pretty tight to me. With 1.88 valves this goes to 104.4°. Either probably work well at 108° LCA. DV states cam grinders generally recommend a wider LCA to compensate for the more (duration) is better adage. Tames the over camming a bit.
The cam I am using is 210@ .050", 256 seat to seat, and .472" lift, ground with 109°LCA. The formula recommends 107° or 108°. I have the cam with the lifters I took out of the 351. Drilled a 2×4 to keep the lifters with the lobes. 1.7 rockers will give 0.500 lift which is not bad for a mild street engine in a Fordor.
I pay attention to DV as he is an aerospace engineer, a winning race driver, a winning engine builder that has consulted for F1 and Cup Car teams. Plus writing articles for 7 magazines every month. I would say he knows a thing or two, recognising that a formula like this is something to point a person in a direction. DV also states that a serious build should be tuned for duration and LCA on a dyno. A street engine application is not as demanding. The slightly wider LCA should flatten and broaden the torque curve with a slight loss at peak. Small displacement engines benefit from all the tricks to develop torque, and a street engine benefits from a broad torque curve. A race engine can give up a bit in the torque curve being broad for more power at higher RPM. Specing an engine involves a lot of compromises depending on the application and desired result.
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