I noticed BB Sharp 1.7 rockers used in Hot rod's "Mild Mauler" build. There is no sign of them in Harland Sharp's store. Nothing in Summit either.

Why aren't they strongly demanded for Big Blocks? I know some possible excuses...

My heads dont flow better above 0.50":
That might be true for a 906. A typical aftermarket head sees cfm increases up to 0.75" and dyno improvements up to 0.80" lift

I would just get a bigger cam (lobe):
You'll be forced to take unwanted duration. Your hp peak will end up beyond 6500. Low end torque would suffer greatly.

I would just switch to a solid roller:
It helps, but why settle when brand x has the best of both -- low duration achieved through solid roller AND 1.7

I'll have lube issues:
Project 505 and Mild Mauler resolved lube issues

Shafts can't go that high and I don't want to pay someone to machine my heads to a pedestal:
Mild Mauler did it without machine work. Mopar shafts should be an advantage, not disadvantage. If demand was strong enough, I'm sure the aftermarket would iron out glitches.

Call Harland Sharp and ask to talk to Randy. They can and will make you what you need. 440-238-3260. Good-luck

Do you WANT or NEED 1.7s? Or are you simply making an observation?

They're available, but not from every rocker manufacturer, and not necessarily as a shelf-stock part.

Love my 1.75 rockers. Have friends that run 1.9 rockers.

If you read through the Trick Flow head thread you'll see that swapping to a higher rocker ratio isn't always a magical experience.

More than anything else pushrod clearance becomes an issue--heck a 3/8ths on some heads with a 1.5 makes you grind--1.6 ratio can drive you crazy grinding in a "delicate area" with risk of blistering or punching through
we use a lot of 1.7 and bigger on SBC circle track engines but it is just not needed on the Mops IMO what the heck will a magic 1.7 do that a well planned out 1.5 won't? IMO not that much and for sure hardly worth the extra effort
I know that if you are aiming to win a contest on the dyno when every single HP counts well then maybe but who needs a street strip engine on a 50 year old car that is that "scienced out"

^^^^^^^^This^^^^^^^^^^

There isn't enough room to get the push rod close enough to the shaft and you can't make it much longer on the other end.

I know those 1.7 rockers are made, or can be made but when I was doing my W-5 deal I spent over an hour on the phone with Wayne Jesel with him talking me down off the 1.7. He would build them but didn't think there would be a pinch of [censored] difference and also said I would probably never get the geometry correct without some welding and moving.



Sometimes it just ain't worth it.

I've done a lot of testing in this area but I don't have any exact wisdom to share. You can easily get 1.70 rockers if that is what you want. T&D sells them and so does Harland. If you are willing to machine your heads then you can get Jesel rockers in ratios up to at least 1.85 which is what I have on my Indy EZ heads.

The real question is what are you trying to do and do you need more rocker arm ratio in order to achieve that. When NASCAR engine builders were told they had to use flat tappet cams then they figured out that a ton of rocker arm was the solution to their need for lots of velocity at the valve. That doesn't mean that the average bracket motor needs either a bunch of lift or a bunch of valve velocity.

If you wander thru the Super Stock pits at any NHRA race and talk to engine builders you'll find out that a lot of them use rocker ratio to solve the problem but not always.

If you haven't read my article in Car Craft go find it and read it. I spent a bunch of time and money testing different rocker arm ratios on my 470 low deck. Zero power increase. We don't know why exactly but I suspect it is because the heads are already close to sonic choke so the extra valve velocity and lift were wasted. I could figure it out with more testing but even I have limits on the amount of time and money I'll spend on a project!

Yea! Gimme a 1.5 ratio and a 5/16ths pushrod so I don't even have to look!!! Toss them in and roll!! I have to tell the truth--Since the Sidewinder head has come along and..it needs a serious grind to get 3/8ths to clear I have gone to a smith Brothers 5/16ths pushrod against all conventional wisdom and guess what?? engines make same ole HP--run great NO issues with even solid roller street cams and...I never ever have to grind or even think about something rubbing--no big on a roller but can be death to lobes on flats so...why not?? and...they are cheaper
Smith Brothers can tell you FOR SURE what diameter at what length with what open pressure will work--They KNOW
Yea run a 7/16ths and tell me you got if all figured out and yea..tell me about the Spintron you saw--I will tell you I Love me some 5/1ths and 1.5 ratio
I have seen on the dyno that a .120 wall vs. an .080 helps a teeny bit at above 8000 on some SBC's but we don't turn that and we ain't a SBC now are we?? I call it Trick weight savings!!!

Here is a set of Harland 1.7 intake and 1.5 on the exhaust. In theory this should be a very good setup but it didn't pick up any power over a 1.5/1.5 set on this engine.

I have gone to a smith Brothers 5/16ths pushrod against all conventional wisdom and guess what??

Its the mopar world on the no go 5/16, 3/8 or its WRONG, the chevy guys have done it forever, smiths 5/16x.116 have worked flawlessly in everything and if you notice it seems they make alot of the middle of the road heads to use 5/16 rods.

I swapped out the Smith Bros 3/8x.088 wall (I paid for .120 wall 3/8 originally ) pushrods after one folded up and broke into two pieces during a dyno pull on my old bracket 526 C.I. 440 block. I had to have the lifter bushing repair after one of the pushrods gouge a groove in it when that lifter pop out at 5600 RPM and broke the tie bar on the Crower Ultra roller lifters and gouge the cam lobe
I bought a set of Manton 3/8x.120 wall Series three pushrods and went back to the dyno for more testing after fixing everything on that motor, I made several pulls to make sure the motor was happy with the old Smith Bros. pushrods (they did replace the two bad ones with new .088 wall for free but not the broken lifters) and would repeat on the power and torque. I then swap the pushrods with no other changes and the motor made 8 HP more at 300 RPM higher peak HP RPM than with the 3/8x.088 smith Bros.
Getting the correct parts needed for the most power is essential to success on motors
My new bracket motor has the Jesel pair shaft chrome moly rocker arms on it with Manton 7/16x.145 wall pushrods in it

Cab, on that build you reference to, what did you come up with the reason it ate a pushrod at only 5600?

SBC pushrod diameter vs. 440 pushrod diameter = apples vs. oranges.

Arguing pushrod size........kidding right? Pushrod size and wall thickness is dictated by the spring pressure you run. It's that simple.

Shouldn't length be considered too when determining diameter and wall thickness?

YEP

What makes you think the pushrod failed first?

I ask because in 1988 I was breaking rockers so fast it would make your head spin. It would kill a PR, eat the lifter and tear down a lobe. Everyone said it was the pushrods. So I bought double taper pushrods. Now I had broken rockers and lifters. So I changes from the MP ductile rockers to Crane gold. Now I only had broken rollers.

It was the roller that was failing the entire time. Because of that, there a two cam companies I will never ever use again.

You call Smith Bros and they ask length? pressure open? Power adders? then they tell you what wall thickness AT THAT length will work --Monte is correct--that is all there is to it
I am guessing Cab found 8 more HP because the rings were seating?? No snub to Cab I think he knows his stuff and I could be way off so...no harm meant just asking
I know longer push rods like on an Indy head etc is the length where yea maybe that 5/16ths is not the way to go AT THAT LENGTH
I get that