I have a question on changing from a 1.5 to a 1.6 rocker arm, (with a solid lifter cam).
Ignoring the fact, if the spring and pushrod can handle the accelerated movement and lift. On a mild performance street engine (sbc), should you change both Intake and Exhaust, or just the Intake side? I know in the past, it has been stated that you should only change the Intake side. I believe that reply was geared towards more of a race engine, than a mild street engine.

Thanks,
Fred
1969 Chevelle SS 396, back on the street after
a twenty one year sleep. (1983 to 2004).
I pulled it out to sell it and the wife asked me
to keep it and put it back on the road. Believe that one or not..... I'm still shocked.

What's the spec of the cam? I know Pat Kelley runs 1.6 rockers on his daily driver with the generic 204/214 cam and says it responded well to the extra lift. You might want to state the specs on the cam and see if Pat chimes in.

I know that I've also heard that sometimes on some heads, the pushrod will rub the head with the extra lift. So before installing all the 1.6 rockers, it might be a good idea to check for clearence on at least one cylinder on each head.

**Edit**

Pat is running the 1.6s on a hydraulic cam in his driver. But I think i remember his race car has 1.6s on it also.

You won't know until you try it. Every engine is different. Some like the exhaust, some like the intake.

I've heard of higher ratio rockers on the four corner cylinders, but not on the center four. Go figure.

is it really worth adding actual true alum. roller and roller tip 1.5 ratios or 1.6's over stock stamped rockers? its either a little cam or 1.6 rckers on the stock cam. i was just curious.


aaron

I thought all BBC's had 1.7 rockers, don't they??

Yeah, stock ratio for a BBC is 1.7 graemlins/waving.gif

I don't know if you have a small block or not, but...

David Vizard has stated that dual pattern cams typically gain torque and HP with the 1.6 rocker on the intake. If you put 1.6 on both intake and exhaust, the HP will tend to increase but torque may suffer. So, if you have a single pattern, go 1.6 on both intake and exhaust.

Originally posted by SS4speed:
I have a question on changing from a 1.5 to a 1.6 rocker arm, (with a solid lifter cam).
Ignoring the fact, if the spring and pushrod can handle the accelerated movement and lift. On a mild performance street engine(sbc), should you change both Intake and Exhaust, or just the Intake side? I know in the past, it has been stated that you should only change the Intake side. I believe that reply was geared towards more of a race engine, than a mild street engine.He does indeed have an SBC^^^

Thanks guys, just the answer I was looking for. My Chevelle still has a 396, but not the original one. The original owner put a rod into the side of the block.
The question was really just a basic question, that ties into a 383 that I put together for a young gent just out of college. He wanted a ton of low end torque, so we selected a low lift cam, 450/450, with an adv duration of 274/274. The heads are 2.02/1.6, which have been ported (not polished). It has been fully balanced (by the same guy who balanced my first 327 in 1973). Static compression is around 9.5. It screams to 5.5 K, but he wants to try to get a little more, maybe up to 6K. It seems to start losing a little pulling power after 5.5K As a misc note, the carb is a Holley 750, mech secs. Short of changing a cam, we wondered if adding 1.6 rockers would do the trick. After hearing the above reply, we plan on giving it a try.

Matt, that Camaro is one of the nicest ones I've ever seen.

Thanks,
Fred.
graemlins/beers.gif

I would think Crane's old 274H06 cam would go good in a hopped up 283 motor AND should go above the rpm you mentioned!!

How are the valve springs??

pdq67

PDQ, unless you miss-typed, you misread his post. It is a 383 he's working with not a 283.