The Stovebolt Site Forums The Shop Area Engine Shop Valve rotators on a 235 head?

Hey guys-

So I found a '61 235 head with the 3836848 casting number and good rocker assembly at my favorite local yard. I'd like to have it rebuilt for use on my '59 261 block for that nice 9:1 compression ratio I've been reading about. I was considering taking the exhaust valve rotators from the original 261 (3836850) head and using them on the 848, and maybe the beefier springs as well. Is this worthwhile?

I've read the 261 valve rocker arms are supposed to be beefier, but those on the 235's I've seen look stronger to me- with a tall spine along the top length of the arm, while on the 261 they are flat and thin on top.

Either way I'll probably use the 235 rockers because they are in better shape. I bought new valves, guides, seals from LMC- (Not stellite- I don't mind the lead additive). Do the springs typically need to be replaced at the same time?

I've never seen a broken 235 rocker. They are pretty stout. I would use whichever rockers are in better condition.

Its not a bad idea to put rotators on the exhaust valves, it makes the seats last longer. I'm not so sure the springs are beefier on the 261- the engines have about the same rev range before the valves float.

Don't expect 9:1 from a stock head unless you mill it a bit. It's more like 8:1.

I broke several rockers on my 248 due to old gas. Snapped right in half. I figure the puchrods would have bent first, go figure. Took some off a 235 to fix it. There are 2 types of rocker arms, the ones which are flat and the ones that have that beefy rib don the middle which I would use if you got em.

I would replace the springs, if they are orignal they are 46 years old. Sounds like you are going to do a through valve job, springs and valve keepers should be replaced.

Sean

This is from the 1960 shop manual. "Springs should be compressed to 1 27/32" at which height it should check 65 pounds for Thristmaster 235 engines and 78 pounds for jobmaster 261 engines. Weak springs affect power and economy and should be replaced if not within 10 pounds of the above load."
I'm also building a 59 261 with an 848 head. I'm using 1.94 powerglide intake valves, 261 springs, and 261 exhaust stellite valves. Also from the 1960 manual "261 exhaust valves have hardened stellite face and hardened valve stem tips."
I also had a used rocker assembly. The rocker arms were all in great shape, but the shafts were quite worn. $32.00 for a pair from NAPA and they'll be here in a week.