I was told you can use a 69 rocker setup on a 70 350 head using 70 pushrods and lifters. I was also told you gain 5-8 in hp. Is this true? To make this work do you have to drill the rockers to get oil up and into the heads?
Yes, you can run the 69 rockers on the 70 head as long as you run the 70 up lifters and pushrods. On a side note, I have seen quite a few 1970 350 Buick heads that had the rocker shaft oiing holes drilled in them form the factory. Jim Burek
Jim, Are the BB and the SB rockers the same too ? I think I heard that somewhere can't remember for sure. I wanna say I was told that the shaft lengths were the only difference, correct ? later,,,,,,,,,,,,
Correct, Dave, the rockers are the same between the engines, the shafts them selves are different. Jim Burek
Eeeeek! I probably should have done more research on this topic before I made arrangements to purchase a set of 70 heads for my 69 350. What needs to be done to these heads to make them compatible with my engine? The plan is to have some porting work done on the heads and set them up with a set of Roller Rockers. I also plan to look into running a hydraulic roller camshaft. I guess I could always send them your way to be set up Jim. WHat is it about the 70 heads that makes them favorable to the 69 heads? Aubrey
I had this same question. So, just bolt them on the later heads and use later pushrods and lifters. That simple? I will be doing it on a 350 and a 455. Now, is it true about a hp gain?
I think the ratio on the '68-'69 rockers is 1.60 and the '70-up rockers are like 1.55, that's where I'm guessing the HP difference comes from.
If you are considering roller rockers anyway, you absolutely need to have the oiling through the pushrod set-up. There are really no differences between the 69 and 70 from a performance perspective. Jim Burek
Hi Jim! this is Rob's (Tubbed) brother... I was talking to Dave at TA and he recommends that I use the hybrid push rod (69 head on one side and a 70 head on the other...) What do you think? Is it necessary? I was thinking it might be because the length would be different. Dave said if I tryed using the 70 rod, it would eventually wear out the cup in the rocker. Any insight on this? Off topic... I can't wait till Rob's motor gets dynode! I am waiting to hear what numbers you get so I have something to reach. I am just hoping I can some what keep up with him. :grin:
John, I definately see no problem with the hybrid pushrod set-up. I have used 455 style pushrods on 430 rockers for years without a problem as well. For some piece of mind, use the hybrids, but I don't believe it's absoluttely necessary. Jim Burek
