Don Terrill’s Speed-Talk

What is the highest lift solid cam that can still be considered,
"streetable"??

I am thinking the MOPAR lifter diameter??

But please post up about the SBC lifter dia...

Thanks,

pdq67

How much lift before your retainer hits your valve seal?

What is the max rocker arm ratio that will work on your heads?

Stan

If it were me and not having maintenance all the time keepin me from having fun - I would only use a .550” lift before lash is subtracted (gross) on a solid flat tappet. You can go much more but the fun factor is reduced by maintainence and springs that don’t last and cost lots of money.

Lot of factors here . you need to define YOUR criterium and expectation of "streetable"..

I am going to throw this out there.. In a flat tappet street strip sbc build ABOUT +/- .347" cam lobe lift the tradeoff of wear VS engine performance GAINS tends to start roll off of benefit..
On a SBC you can juggle rocker arm ratio for effect.
It is more important that valve events occur at the right time in the cycle and there is enough valve open flow area available and the valvetrain is also dynamicly stable yo RPM
Than getting the most sexy high valve lift.
On a sbc the intake side seems to respond to rocker ratio more than the ex side does..

More valve lift tends to mean quicker valve guide wear.
Especially if the guide is shortened..
On "Street roller" cam stuff I like to keep the roller cam lobe under .400" lift... There is a ton of room to play within.

On a high perf sbc flat tappet deal a slightly ROUNDER over the nose cam lobe radius tends to wear a bit better VS a pointy nose with a hair more lift...
Again lots of factors.

Getting the geometry right is A BIG FACTOR.

First,
You need to define your definition of 'streetable'.....which will probably differ from others......

F-BIRD'88 wrote: ↑Sat Jul 25, 2020 7:09 pm It is more important that valve events occur at the right time in the cycle and there is enough valve open flow area available and the valvetrain is also dynamicly stable yo RPM
Than getting the most sexy high valve lift.

Totally true.
Got the cash, then pay an experienced professional builder to assemble a package that will meet the desired performance goal.
Otherwise you are risking to end up with a pile of broken scrap parts.

Lift does not make a cam streetable. Valve opening, closing and other events make that happen. If you want a car with good street manners than always put it on a 114°LCA. You may give up some low end torque but it will be more streetable for sure.

I am not trying to start a contest- and you guys are not wrong exactly, but responses like these are kind of short sighted--

1980RS wrote: ↑Sun Jul 26, 2020 5:41 pm Lift does not make a cam streetable. Valve opening, closing and other events make that happen. If you want a car with good street manners than always put it on a 114°LCA. You may give up some low end torque but it will be more streetable for sure.

yes but---- too much lift can make an engine "unstreetable" because it can be harder on parts compared to the owners budget and maintenance preferences.
And in my opinion- just choosing 114 LCA shoots your opening and closing points idea--if you have correct open and close points LCA falls where it will.

To help this conversation along, as others are getting at, it's best to better define streetable.

Do you need vacuum brakes?
How often are you willing to change valve springs?
How often are you willing to check lash?
How much (thick) pushrod can you run?
How much RPM will you spin it with any regularity?

Others prob have more/better questions to help flesh out what streetable is.

pdq67 wrote: ↑Sat Jul 25, 2020 12:36 pm What is the highest lift solid cam that can still be considered,
"streetable"??

I am thinking the MOPAR lifter diameter??

But please post up about the SBC lifter dia...

Thanks,

pdq67

Like other said, Streetable is different to everyone.
I would look at how much spring pressure you want to run on the street. I would say a cam that requires less then 360# of spring pressure at max lift is streetable.
One of my customers builds a lot of Ford Cleveland engines for the street, and runs a 244/252 @ .050" with .365"/.364" Lobe Lift, and 1.73 rockers. That's over .600" lift, but since they're large stroke engines, they don't turn a lot of RPM, and don't require a lot of spring pressure.