FastWhiteTA

I'm thinking about putting 1.6:1 roller rockers on my car. Got a few questions 1st though:

I understand the roller rockers have a lot less friction than stock rockers, but my question is this.....does the combination of high ratio/ roller rocker overall cause MORE or LESS stress on the valve train of the LT1 compared to the lower ratio/non-roller rocker combination? And does anyone know how much rwhp I can get out of a good set of 1.6:1 Pro magnums? I have full bolt ons on my car, dynoed over 300 rwhp and 340 rwtq. Stock Cam and heads. Any help would be MUCH appreciated, thanks!

Gangly

Doesnt really cause more stress on the valvetrain. The rocker arm acts as a lift multiplier and will in effect work the springs a lil harder so i would not reccomend you install 1.6's on stock springs especially if you have a "few miles" on the car. Also, on occasion but not often, when you install the rollerrockers you will start to break rocker arm studs. I went through 5 and upgraded to ARP 1.89" studs(if i remember correctly, i can look for you if you want) and never had a problem since. i HIGHLY doubt yours will do that, mine seems to be a freak instance even though the valvetrain geometry was correct. Basically, other than a fresh set of springs if you have a high milage motor, you are good to go. You wont make gobs more power, but you could prolly expect to see 5-7 rwhp on a good cold day. Just make sure you set the lash correctly or you could mess something up pretty good.

Aries

I picked up 5 rwhp with 1.6's, and used the LT4 springs with them.

solid95z

iTrader: (7)

Darryl is that you?!?!?

Basically when you add 1.6 rockers you will be increasing the lift of the cam by an average of .030". Which will inturn stretch your power band a bit and up your rpm a tad also.

I put CC Pro Mag 1.6 rockers on my car when I had my cam only motor (212/219 505/529 w/1.6)and gained about 100 rpm or so. I dont know what I gained from them since I did not dyno the car without them. I would guess only a few hp.

If you are going to get new rockers, make sure and get 7/16 rockers and hardned 7/16 rocker studs. Those are bigger and stronger and they are the same price. It is definately worth it.

As stated earlier you may wanna go ahead and get a set of valve springs also. The rockers will add some stress to the springs.

Scott

FastWhiteTA

Thanks, I was hoping I'd be able to get 10 rwhp out of them..but also having to buy some springs, I might not do it if I can only get 5 rwhp. But, I'd have the springs set up already for when I get a cam though. That wouldn't be too bad then.

FastWhiteTA

Yeah this be me Scott. How difficult is it to put 7/16" studs in?

Gangly

you just have to re thread the heads....not worth it really unless you are putting some really serious/stiff springs on there. If you are gonna change studs, i would go with the 3/8ths chromoley studs. There is no re-threading, they screw right in, and they wont break unless you go a monster cam with some crazy stiff springs. For 95 I believe the lift on the stock cam was .447 and .459 with the 1.5 rocker arm. Since you are adding a 1.6RR which is basically a multiplier, you divide the lift by 1.5(original rocker arm size) which would give you .298 and .306. Now multiply that times 1.6 and you get .4768 and .4896 for an increase of roughly .030 like Solid95z said. However, as the cams get larger so does the effective lift with an increase in RR size. Say for instance you have a .510/.510 lift cam, add 1.6 RR's and then the lift(not actual cam lift from the lobe) would be .544/.544 which is an increase of .034 which is basically just to show that the .030 isnt a rule of thumb when speaking in terms of larger cams.

solid95z

iTrader: (7)

Actually you don't have to rethread the heads at all. The bottom of the rocker stud will still be 5/16 where the top(where the rocker will sit) will increase from 3/8 to 7/16. You'll just have to take off the old rocker studs and put in the new ones and then reset the valves with the new rockers.

Gangly

interesting, the 7/16ths one ive seen had larger bases as well I thought. I guess im wrong, sorry for the misinformation

96-speed

iTrader: (19)

7/16s here - no rethreading needed. At LEAST upgrade to the ARP studs.

Ryan