CNC Dude is right on the money.
78 granada":17vuynrl said:
The ones I have in there are 9.300 which is essentially the length of the stock rods I took out. There may be a margin of error going to the cup configuration I suppose. Looking at going to a 9.100 length which will give me a lot more thread all things being equal. What would be cool is if someone offered different dimension adjustable rocker ball ends!!!!!!!!!!!
That is also the truth.
Adjustment balls and the pushrod cups and pushrod types are variable. Some are oil through for some roller rocker applications.
See the pictures Bob the builder supplied between the CI and other types.
Not knocking Yella Terra, they have reaqlly done the hard research work, but for example, replacement Yella Terra adjustment balls are different to the stock worn 1960 to 1966 144/170/200 adjustable shaft balls.
Talking the 1.666" shorter 7.803" tall crank to head gasket deck 200 cubic inch block as an example over the 250's 9.469" deck.
Way back when,
Rick Smol had problems with them in his 250 2V M code 170 HP head on his 120 hp 200 1-bbl block engine in his Mustang. The ball adjusters were sheared with just a moderate lift Schnider split duration cam. It wasn't the came that dislocated the pushrod, it was a adjuster ball to pushrod cup issue.
The recommended Aussie 250 2v head swap actually uses 186S General Motors Holden pushrods and roller rockers, but they require a 302 Windsor hydraulic lifter, and the US 250 is a few thou taller than the Aussie 250. Rciksmol had to find some other pushrods to suit his Yella Terra rockers and rocker shaft, and it failed to work with the adjusters.
He just took the stock rocker gear, and reverted back to non roller rockers, and it worked with the stock pushrods.
Down here, we used 2-bbl 1968-1971 Holden 186S adjustable rock pushrods, which were used on some 2650/ 3050 Torana and Monaro two door coupes in 161, and 202 engine sizes as well, some with triple carb XUI GTR Toranas. They have been known to shear off the adjustment balls if they don't match.