Hey guys I have a 425 in a 69 442 just purchased. Someone put adjustable roller rockers on and had 3 different lengths of push rods. I bought the correct pushrods and got a set of arms off a 350. The problem is the bolts that hold down the rockers are 5/16 and my screw in studs are 7/16. Would this have had adjustable arms from the factory with these screw in studs? Thanks

 

No it would not have screw in studs. that is probably part of the aftermarket roller rockers. What heads are on the engine? (letter next to #1 spark plug) an original 425 could be 65 66 or 67 and would all have different heads. But the rockers are all the same on the engines. I can supply correct rocker arm bolts if you need them.

Best to email me direct or call me.

Larry Moyer
Redmond Oregon
Olds Parts and More
lemoldsnut@aol.com
541-815-4363

 

does it take a 5/16 bolt from the factory. Like I said mine are 7/16 holes in the head now. I am not at home to look at the number right now

 

1965 "A" heads on 400s and 425s had 3/8" threaded holes for the rockers from the factory. Every BBO head since then came with 5/16" holes. If yours really has 7/16", they have been drilled and tapped by a previous owner to use aftermarket adjustable rockers and stock will not fit. Are you sure the HEADS have been drilled and tapped oversize? You can buy rocker studs that have a 5/16" lower thread and a larger upper thread. Also, if these heads have been machined for studs and guide plates, then the surface on the head that the rockers mount to is likely to have been machined down and again, stock rocker bridges will not work. A photo would help us tell you what you have.

 

What valve springs and spring pressure do you have ?

 

Instead of trying to go back to stock, which were non adjustable, why not just buy the correct pushrods to make it work. The adj setup is much better but requires adjustment for the initial install and nothing after.