Many years ago at a track far away my brother in-laws '70 Road Runner decided it no longer wanted it's crankshaft and spit it out in two pieces making a very big mess and making my b.i.l. very sad. After sitting for a LONG time, he decided to get the old girl running again and we started building a new engine. At this point we have a 507" RB shortblock (4.36 bore, 4.25 stroke) with Icon dished 842's .007 deck height, H-beam rods. He wants to reuse his six pack induction and has a .600" lift Lunati roller. He also has the Harland Sharp rockers that were on the 906 castings the car had. Our intention was to use his ported, big valve 906's, but after sending them out to be magged and to freshen up the valve job we discovered they were both cracked below the center exhaust ports.

We decided that since the heads showed signs of weeping and that it would only get worse new heads were in order. The Trick Flow heads were looking like a good match and we were ready to order them when we started to hear of a scrub problem using the HS's and that HS had actually made a separate rocker for these heads as the original rockers are too long and the roller is too far back on the valve. I think I saw AndyF mention this as well in another post. We called HS and they said that there was an issue but it could be solved by using lash caps. Not really the way I want to go honestly. So at this point I'm wondering if anyone has already addressed this with the TF heads and the original HS rockers? At this point he's put out a lot of his available funding and really doesn't want to have to put out another $1000 for new rockers on top of the $2300+ for the heads. If this proves to be the case, we may have to look at other heads that will bolt up to the OE 6 bbl manifold, use the HS rockers he has and work with his Icon pistons. We have talked about using Stealths but I really never got over their early quality problems and they still scare me. Any thoughts on this would be appreciated as we're kinda stalled out atm and are open to suggestions on making it work with the TF heads or an alternative head choice. Sorry for the long novel

Sounds like you know what the situation is.

Just need to decide on which way you want to go.

You could always sell the current HS rockers to offset some of the cost of the new ones.

I haven’t tried it myself, but supposedly the std HS rockers fit the Stealth heads okay, however the RPM heads exhibit the same kind of fitment with them as the TF’s.

I haven’t checked with the speedmaster or sidewinder heads either....... someone here might know though.

"Use lash caps" frequently means "I don't know the answer, and have no idea what caps will do to your geo".
They may make it worse.

Andy f also said there are some other rocker that work on those heads, if it's a street car the other ones that work may be fine for your app. and you could sell the HS one's .

There are lots of rocker arms that fit those heads, you just need to pick your poison and get it together. Sell the used HS rockers to raise some cash.

https://www.hotrod.com/articles/trying-find-extra-power-rocker-arm-testing/

B3 Racing Engines LLC
PH: 717.497.6572
Email: contact@b3racingengines.com

http://www.b3racingengines.com/contact.asp

I bought a set of the 440 stealth heads not long after they came out and haven't had any issues with mine. I did buy a set of TF 240 last winter and picked up nicely with them. For just a street cruiser the stealth heads would be fine, but if you want the extra power I'd recommend the TF. Keep in mine the stealth heads you'll probably be able to use the stock length pushrod where the TF you will need a longer pushrod. I used Crane gold rockers with both heads without any issues. I used both in an all out race motor that I shifted at 6000 and ran a .557-.590 flat tappet MP cams so it's mild by a lot of people standards.

My story is almost the same. Switched from Stealth's to TF 240 and got a very nice power increase. I did also change cam from hyd ft to mild Solid ft (248@.050) but otherwise no other changes. I also use Crane gold rockers on the Trick Flows, and yes, longer pushrods are needed. Good luck

The std HS rockers are a good fit with the Indy EZ's and the base head from ICH has a stock size intake port which will line up with the 6-pack intake. Those are a little cheaper than the TF 240's as well.....but you will need better springs for the roller cam so it's probably a wash in the end.


Ron

I've use lash caps on every solid roller cam motor I've built after having to file the top of all the valves that the spring pressures from solid roller cams had mushroomed the valve stem tips(tops of the stem) out enough to not allow them to slide out of the valve guides
Lash caps are your friend on solid roller cam motors, especially if your using stock type valves
Make sure and get the pushrod lengths correct also, one to three complete threads showing on the adjusters under the rocker arms
IHTH

Did you ever have the old 906’s flow tested?

More than likely, a set of cleaned up Stealths would outflow the old 906’s...... and since if the 906’s weren’t cracked you’d be reusing them....... they should work at least as well as what you were originally going use.

That’s the least expensive path forward.

A set of “stage 1.5” Stealths will outflow all but the very best 906’s(285-290).
Ootb they’re usually in the 255-260 range.

Thanks everyone for the replies, great information and advice as always from you guys!





No Dwayne, never had the old heads on a bench to know what they flowed. The 906's had the old crappy MP valves and were only mildly ported, so I have no doubt that OOTB Stealths will make a lot more HP than the old 906's. And yes, they are much cheaper (more than 50%) than other head choices but they also will make less HP, require someone making the VJ right and replacing the springs and possibly the valves. I have no idea if the valves they come with are any good with a solid roller and moderate spring pressures? So after all of the things that need to be done to make them "right" for his combo they really won't be that much of a cost savings, maybe none at all.






You make a good point Cab, the lash caps are great for taking the beating of the solid roller, even though this one isn't that wild, it still will have fairly stiff springs and sharp roller ramps. The issue I have is I have no idea how bad the scrub problem is. Is it offset by .010 or is it off .250? I'm ok with lash caps, just have no idea what I'm dealing with in this scenario. I know it was bad enough for HS to make a separate rocker for the head, so that tells me that that geometry is off more than a little bit. It's all of the unknowns that have us stuck where we're at. Not having access to the parts beforehand to touch and feel them in person makes it really hard to know what direction to go.

Actually...... it’s not that HS made rockers for the TF heads.

HS made rockers for RPM heads(hence the “E” at the end of the part number), and apparently those are what TF used to determine where to locate the rocker stands relative to the valve tips.

The E rockers existed before the TF heads came out.

I attended two of the old (prior to 1980) Mopar drag race seminars that Mopar use to put on, Tom Hoover spoke about the valve and rocker arm sweep pattern and they like to see the pattern start on the inner (closer to the rocker shaft) 1/3 of the stem and then sweep across the center of the stem and end up on the outer 1/3 of the stem at max lift, that has worked very well for me for a lot of years
You can use dykem or grease to check the pattern, set the lash first and then check it out
I have had a little valve stem and keeper groove issue with lash caps also, but the open pressures where above 830 Lbs. and I was shifting the motor at or above 7000 RPM

I run my old Crane 1.5 rockers on my tf270s .
Ran these on stock Stealth and then CNC Stealths . If you run Stealths just step up to the CNC version , they make more power . BUT not like the 270s 😁
I did upgrade locks , retainers and springs on the stealths to suit , i run solid flat tappet cams

Tex

Might want to read This Thread before getting ideas about NEW CNC Stealth heads.

OP...605ply nailed it. You don't need lash caps. Almost never. Lash caps will make it worse.

It's criminal that HS and a host of other either lie about your issue or are just ignorant. When I was younger, I thought they were lying. After 6 decades of life, I now know they are mostly ignorant and just don't give a single [censored] about anything but selling you junk.

You need a rocker arm geometry education. Go to the b3 racing engines web site link above and read his tech articles. Once you get an understanding, you can call Mike and he will help you fix your geometry and it won't need lash caps.

Your valve train will thank you. Mikes prices are so reasonable and his stuff works so well there is no excuse to not correct your geometry. There is no way that HS doesn't know about this, because I've personally called them. They just don't give a [censored]. A sad fact. If they actually gave a [censored] about you, the customer, they'd work with Mike to help their customers get the best. GM guys don't have to deal with this [censored]. Why do Chrysler guys put up with it?

If I sound a little pissed off over this it's because I am. There is no excuse for jacked up geometry. In fact, it's not really even HS' fault. Or any other manufacturer for that matter. They can't control the height of the rocker arm shaft saddles, or the length of the valves, both of which affect geometry. There are design details they can control, but those they can't.

So skip the lash caps and the other band aids and call Mike and get your stuff fixed. Making the valve longer with a lash cap won't fix a thing.

THIS ^^^^^^^ you can see the shims on mine.they raise & move the rockers towards the intake side.

I may be able to save you money on a package deal. Give me a call, and I'll see what I can do for you.

717-497-6572

Thanks for the link, sad that Bob's having trouble and I hope he works it out. I knew Jeff for a long time and used to stop in to the shop and BS with him from time to time. It was a great loss to the Mopar world when he passed.