[1968 hot rod]

Mark,
Have you ever found power adding a stud girdle to a bbc engine with a roller cam and iron heads?

 

[VinceS427bb]

Mark,
Have you ever found power adding a stud girdle to a bbc engine with a roller cam and iron heads?

what kinda spring pressures are you working with??
and what pushrod OD and thickness are you using?

 

[bracketchev1221]

Only thing I ever saw was it held the poly locks from loosening.

 

[bradley67]

It definitely stiffens up the valve train when running higher spring pressures. I like them and normally run stud girdles. But I’m running more than 500 over the nose and spinning it to 7k.
Can’t comment on any additional power.
If your flexing the rocker studs (without a girdle) you have bigger problems.

 

[68Chevele]

I have run a stud girdle on both of my SBC and BBC's. It really helped the SB, but since I do not spin the BB very high there was no change for me other than they keep your valve lash more stable.

 

[1968 hot rod]

240 seat 600 nose pressure.
I know what they do and what they can help with.
But that wasn’t the question.
I’d like to raise the rpm over 7400 which it starts popping at and utilize my looser converter and higher gear.

 

[pockets]

If it starts popping it's obviously going into valve float. Which can be from insufficient spring pressure, pushrod flex, incorrect pushrod length resulting in poor geometry, incorrect lifter for the application (hyd roller).

 

[bracketchev1221]

240 seat 600 nose pressure.
I know what they do and what they can help with.
But that wasn’t the question.
I’d like to raise the rpm over 7400 which it starts popping at and utilize my looser converter and higher gear.

What’s in the heads? I couldn’t control my steel head parts at high rpm and that was a .725 roller. I went to 2.25/1.94 11/32 stem valves with k-motion 1000 springs with titanium retainers to finally control it. 3/8” stem valves and steel retainers just wouldn’t do it. After that I ran 1000h springs for several years and then went to Manley Nextek springs. I was over 300 and 800 with the last springs.

 

[GoFast Beaumont]

Has anyone done spintron testing with these on and off?

id be interested in seeing if there is movement even on a stockish setup at something like 2000 or 4000rpm.
People always say if you 2-250 on the seat or more you need one, just like some reasoning where that number come from

 

[1968 hot rod]

I do have 3/8” stems and ti retainers.
The cam isn’t above .700 lift it could be floating the valves a bit, the inj is getting pretty rich up there or maybe it’s just outa cam.

 

[VORTECPRO]

Mark,
Have you ever found power adding a stud girdle to a bbc engine with a roller cam and iron heads?

I never back to back tested it.

 

[1968 hot rod]

I never back to back tested it.

Ok thank you

 

[VORTECPRO]

240 seat 600 nose pressure.
I know what they do and what they can help with.
But that wasn’t the question.
I’d like to raise the rpm over 7400 which it starts popping at and utilize my looser converter and higher gear.

It is closed chamber?

 

[1968 hot rod]

It is closed chamber?

Yes

 

[VORTECPRO]

Yes

Ya know I never had closed chambers carry power, although SS 325 HP 396 get them to turn 8800 RPM in the lights, have you opened up the area between the intake valve and the spark plug?

 

[1968 hot rod]

It’s square port head.
I haven’t worked on the chamber except for blending the chamber and bore.
The int ports stall around .700

 

[1968 hot rod]

Do you have a pic to share possibly?

 

[VORTECPRO]

Do you have a pic to share possibly?

Sorry I don't Foxwell did a set of 063s and the chambers looked good, ask him to post it up.

 

[steelcomp]

Sorry I don't Foxwell did a set of 063s and the chambers looked good, ask him to post it up.

 

[68Chevele]

If you want to spin the engine to 7400 you need to get the valvetrain as light as possible. 11'32" stem valves, ti-retainers and anything else that you can save weight as you have to multiply that little bit of weight and you can imagine what it is at 7400 rpm. This year I got to run my 360 peanut port heads that had the 11/32" stem valves in them, the engine will easily spin 6800, not that there is any power up there with the cam I have but compared to the old heads these do not go into valve float like the other heads with the 3/8 valves did with the same valve springs in both heads. Here is my modified closed chamber, I have not tied them yet so I can't say if they will work or not.

Before and after some porting