We are currently running a .625/.625, 260/270@.050 herbert solid roller with these springs>

https://www.herbertcams.com/1-550-od-195-1-940-solid-roller-dual-valve-springs/

We plan to up the r/ratio to either 1.6 or probably 1.7 (jesel) to get .708...springs will work but would you up the seat/open with the extra lift for better control, I don't think minimal pressure is a good thing necessarily, this will be street driven as well as a brkt car, your thoughts gents, max rpm will be 6500, big wedge motor.

thanks

Just be aware that what platform you’re running can have a big impact on what you need for spring loads.

A set of AFR SBC heads with 8mm stem valves wont need the same loads as a set of Big Chief heads with 6.7” long 2.400” diameter SS valves and 1.8 rockers.

Personally, I would use a “premium” valve spring in your application.
The 600 open would probably be sufficient, but I’d run more than the 195 on the seat your current spring has.

The least expensive spring I’d use for that cam in that motor would be some Isky 9385’s.

9385-plus’s would be better, and 9985’s would be better still.

Not what you asked....... but.......
Frankly, I think a more cost effective option than swapping out the rockers would be to just put a higher lift cam in it.

Have you priced the rockers yet?

It couldn't hurt to use a lighter retainer/lock combo too.

ok thanks, so more seat 220>240, and yes I know, $1350 for jesel 1.7's I think+shipping so around £1300GBP here (ouch!!), as you say it may be cheaper to install another cam/springs.....just trying to get some more out of those -13's, not the best@.600 lift, we need another 60>70hp somehow out of the motor and would be happy for now, lift/carb as its got a puny 950HP on it.

In which case as your the cam guru what cam would you suggest, easy lobes for street but with enough lift 700>720? to help those heads move air and then we can go with a Thumper Dom 1050-ish carb, a 440-2 adapter or a 440-3......hopefully that would help reach our 760hp goal and 9's or at least get us somewhere near....but this is me talking really, my mate is happy to run the same number every time.

Sometimes you need to let the motor tell you where it wants to be shifted at after changing things in the valve train, not use a number you like based on your past experiences
I would try shifting it at 5500 RPM and then increase it up by 500 RPM per run until the time slips tells you what the motor and converter like the best to go as fatst as it can
My old 511 pump gas stroker motor made peak power at 5500 RPM or 5600 RPM depending on which heads, intake and carbs (low deck eddy six pack set up)I ran and it would make peak torque at either 4500 or 4600 RPM.
That stupid motor like to be shifted at or above 7000 RPM Don't assume anything when it comes to changing parts and combinations
You need to test it to find out what it likes

Cab, it liked it as in, it was faster at the track shifting at 7000+?

Yes Cab I'm with that, our combo weird as it is made a peak 695hp@5500>5900, and 724ftlbs@4400, thats exactly what we'll try as you said, unfortunately no time to do it all as were straight into the brkt racing without even a test/tune session I doubt, and the driver has never ran anything like this before, lets hope the little I know from racing back in the day will help him, its gonna be interesting to say the least!!....however as he only lives 4 miles from SPR a few test/tune (RWYB's) is on the cards but the track is not so good on those is another issue, set it up for that and change it again for a better track.

Yes, it ran quicker and faster shifting it above peak HP and peak torque RPM
I had the original converter built off the dyno sheets for street and strip by Contintental, it would foot stall in low gear 2300 RPM max before pushing the front tires through the staging beams, it would flash up to 4600 at sea level.
I tried shifting it from 5000 RPM to 7500 RPM and ended up using between 7000 and 7300 RPM to get the best ET and MPH
I had a VDO playback tach in it as well as a LM1 with the dual O2 sensor kit, I could record the runs on the LM1 and play them back on my laptop to see the rate of acceleration to see when the motor would start to slow down on the rate of acceleration per second. I was up to 7800 in second gear on one time trail and decided then that I didn't need to rev that motor that high on each run so I stop the testing and started racing it by shifting between 7000 and 7300 RPM depending on the track location, length, elevation and weather
BTW, that stupid motor had not stop accelerating well at 7800 RPM

Have him test the shift RPM during qualifying and racing and use the info gather and compare those results from the earlier races
Test, test and test some more

Interesting, thanks for the info Cab I would not have expected that.

How did it do above peak hp rpm on the dyno? Plateau rather than dropped off?

A ratio increase has these effects:
1. the full lift spring load at the valve becomes (whatever it was) × new ratio ÷ old ratio (regardless of actual lift): 500 lbs. × 1.7 ÷ 1.5 = 567 lbs.
2. the spring load on the tappet & pushrod do the same thing

It differs from a new cam in that you can create an intake/exhaust bias, or change it in either direction.

Interesting, however we only have 195lbs seat (200 shown on my paperwork), that will not change I believe and thats what needed, more seat with .700 lift.

That’s “what I’d do”.
More on the seat, same open.

A benefit of the lower ratio rockers on the street is....... less load on the lifters.
The lifter sees the spring load x the rocker ratio.
So, at 600lbs open load, with a 1.55RR the lifter sees 930lbs.
With a 1.7RR the lifter sees 1020lbs.

You may want to check out the tests Andy did with the TF heads and the 4 sets of rockers.
Since you have rockers what are quite expensive ....... I’d want to be pretty sure the money spent yielded enough of an improvement to justify the cost.

Or, looking at it another way...... how much additional power would the motor have to make, from the rocker swap alone, to justify the cost?
Then...... does that seem like a realistic expectation?

Keeping the lifters happy is paramount for street, so if I can persuade him at some point when he's bored with 10.5's its a cam/spring/carb change....for the least $$ outlay. So its the "Street" word that compromises things AGAIN isn't it, same old.

And yes I read those articles, no real gain, however we are going from .625 to .700 on a head that really needs the lift so prob would make more of a gain than nothing, but I see your point on 1.5's and I don't know about geometry with jesels.

Yes, I’d expect a better outcome from a rocker swap in that combo.

But would it be $1300 worth?

NO..and he's just spent around £15000GBP on the motor and trans, a Dana/posi/mono's/shocks/converter etc.. I don't think he'd be too happy with spending much more yet.....This what forums are for, I've got a much better slant on how to go about things in the future with the help of you guys.

thanks

It was going downhill after it peaked,(exactly how much I don't remember now) all the dual plane Eddy six pack intake are known to reach peak HP around 5500 RPM, the later SS Weiand(SP?) replacement two piece intake are probably a higher peak RPM and torque manifold.
As I've suggested that stupid motor didn't know it was a six pack motor, I guess
It exceeded my wildest hopes

Save $$$, only get intake rockers.

We are@.645" with 1.55 RR, less .024 lash = .621, going to a 1.7 intake would make it .708 but I think you would have to open the lash up for the larger ratio, can't remember what the formula is but it'd be around .680 a worthwhile gain and a lift that Dwayne suggested to be max with the street driving thrown in to the mix, but then we are still@.620 exhaust with .025 exh lash, I've seen many rollers have less exh lift with more duration but that seems a touch too much not being an expert on roller cams. We have 2.25" hdrs I think on the car but its run through the full system, I could tighten up the exh lash some but don't think doing that is a particularly good idea, we have enough vtp. Either way we'll need better springs with more seat. Shame I don't have flow numbers for those heads @.600 through to .700 I think we can forget what Indy post up.

You may have interpreted something I said that way, but I don’t remember saying what the max lift for the street was.
I did comment about the max lift I’d go with the springs I suggested.

As I’ve already said....... I’d slip a new cam in it for less that 1/2 the $$$ way before I bought rockers.

There is absolutely nothing special about the current cam to warrant spending a pile of $$$ trying to make it into something it isn’t.