Ha..... Soo they're 3/8ths going into the block. 5/16ths where the rockers go?

And if this is true could I just buy a stud that's 3/8ths all around then bolt right in the adjustable rockers?

 

Yup. Only thing is...go with a different cam and you may find you cannot run 1.7s with it at all. You have to check your installed vs minimum height to see what you have to work with first, and you'll need your heads for that, though some of the guys on here will know the right numbers for certain combinations of parts. I for one am using stock springs so a cam install meant no 1.7s for me.

 

Yeah I found a page about that... Macular I'm gna go with a bigger cam. And valve springs so I think I'll just 1.6

 

I don't want to start a war here but I am 99% sure that stock heads are 5/16 because I had the H&S 1:7 rockers with 5/16 bolts at first but because I had asked Odessa to drill the holes out to 3/8's I had to get new rockers. Hopefully others can comment on which it is.
If you look at the Mopar RR kit it has 5/16-3/8 studs with the 5/16 in the head and 3/8 what holds the rockers. Which was one of the reasons why I didn't buy that kit because I would have had to buy studs too.


For the OP, if you're getting head work done anyhow it is nothing to have them drill out the rocker mount holes and tap them for 3/8's which is what I had done with my heads. Also I think if you look the Crane kit is 3/8's on both ends.

 

You could very well be correct, I do not know for sure.... just basing on what I have read/can guess. if you have direct experience, then I would be more inclined to believe that.

I have a motor on the stand out in the garage, maybe I will go pull one, and see.

 

Please do. It'd really suck if I had to buy 2 sets. Thank you all! U guys are much help!

 

I also believe the stock stud is 5/16".
Typically the only concern with increasing the stud size on stock heads, becomes is there enough meat left around the boss so they don't crack.
Since you're using aftermarket heads, the bosses are usually bigger to account for larger studs as that is a common upgrade on performance engines.

 

Just to make sure i went and looked at a old rocker bolt that I have here, 5/16 is what goes into the head. So I was right in my org post 5/16 into the head and 3/8ths for the rocker stud. I have photo's if anybody needs them. Sorry for causing this confusion.

 

Just glad to have it cleared up.

 

Merc not anyone's fault it just takes someone to verify and confirm. That is what we are all here for.