I haven’t posted enough to post pics yet of how I did my 496 but I used arp studs with comp 1.7 rockers and ran into similar geometry issues with pushrod length and thread depth of the poly locks. I think I used a washer under the arp conversion stud and a shorter pushrod like drag racer art was stating. 1.8 can’t be too big of a jump to be compensated by pushrods but I’m a hobbyist builder at best. If I had the knowledge or tooling to make it 7/16 I’d go that route, I was in a rush and eager to get my engine done and in as it was already mid June when I got the block back

Buona,

What kind of spring pressure do you have? The builder and I discussed the possibility of spacing up the stud, but we both agreed it was only sacrificing one thread engagement for the other, and a net loss of overall strength.

I haven’t seen the stack up with the shorter pushrods yet, but the builder is confident the proper length pushrods will pretty much solve the issue. He says once the lifter is preloaded, the polylock will pulls down a fair bit further and he’ll be happy with the thread engagement.

As for the rocker ratio, the 1.8 vs 1.7 ratio shouldn’t make any difference. It’s the conversion from stamped rockers to roller that has made the difference in geometry. As a proverbial MFR of aftermarket parts, I would do everything I could to ensure the end user could do a simple part for part swap, upgraded rocket studs aside, but I’m assuming that’s not in the engineering cards.

Thanks. Brad.

They were a comp cams dual spring. Needed some machining and different locator on the bottom to get rid of the stock rotator plate. Pretty sure I pieced it together from raylars book and my engine builder that did the heads. Originally ran prw 1.73 rockers but had a failure on my part due to not checking pushrod length. Went with comp 1.7 this go round. Correct length pushrod did solve all the issues and eliminated the spacers I looked back at some pics

After going stud adjustable (from fixed bolt down stud style) I would expect proper geometry would need custom length pushrods.

Tartilla,

The mounting method hasn't changed. OEM is an adjustable stud, and that has not changed with the upgrade to roller rockers. What has changed is the geometry of the rocker itself. They just don't sit like stamped rockers do. In my naivete, I assumed that they would be a drop-in replacement, and didn't realize that they can't be, given the plethora of options that have to be accounted for, like cam base circle, deck/head machining, spring selection, etc.... So, when the builder indicated new pushrods were necessary, I assumed it was the same "496 white elephant" issue, where parts just don't work for the 496, and modifications would have to be made to Frankenstein it all together. I still think, at the end of the day, taller studs would be beneficial, but certainly not a necessity with the spring pressure we are using, compared against the amount of cost and/or work involved in making that happen. The pushrods have been ordered, but I don't know if they have been delivered or installed. I'm sure I'll get an update when they are.

Thanks. Brad.

OEM is not an adjustable stud, rocker nuts are torqued 20-22 lbs

My bad on the poor comms. I'm fighting the same issue on my 088 heads. I can see where GM went with the non-adjustable rocker system...TQ and forget. But any block decking/head machining or head gasket changes would put the rocker geometry off. I'll prob just get the Comp 3/8" to 7/16" studs...for the 088 heads. Mycams are pretty mild, amd I don't plan on having the Iron heads for long.

How is the budget making out 85% of the way in?

Tartilla,

I'm kinda regretting not pulling the heads and tapping them for 7/16-14 studs, just because. But, like you, the cam is really mild and the spring pressure, even though it's way better than OEM, is still not overly heavy.

Trying not to look at it the bill too much. I'm still pretty confident we're going to slide in under $10K, but there's probably a lot of nickel-dime stuff that is going to add up. I'd hate to think what the bill would have been had I just packed it into someone's shop and told them to call me when it was done. I know I've spent a fair bit through the company, disguised as "work", that the CFO isn't going to be made aware of. I'll get a tally at some point.

Thanks. Brad.

BoatNT,

My bad. I didn't realize that. In the absence of me seeing the heads in OEM assembly condition prior to disassembly, I saw a lack of pedestal in the stack-up and assumed. I'm really out of my element with most of this stuff, and most of the process has been a steady stream of filling in the blanks on my end.

Thanks. Brad.