I have a 84 Z-28 with a 355 in it. The motor also has the L-31 vortec heads, Sliv-o-Lite hypereutectic pistons with 4 valve reliefs, stock rods, 268extreme Comp cam 224/230@50 and 477/480 lift. I have had the valve guides cut down .120ths. It has 1.5 rockers on it right now and i'am thinking of trying a set of 1.6 roller tip rockers on it, my big question is will I have any trouble with valve to piston clearance? It is stock deck height and the head gaskets are .40. I had the motor apart just a short time ago and i'am not to excited about pulling a head of to check the clearance. I know that there are some guys out there that are running close to the same motor combo and thought someone may have tryed the 1.6 rockers already, it could save me some money and time if anyone has any expereance with this. Please let me know and it would be greatly apprecated. I f I can run the 1.6 rockers it will bring my working lift from 477/480 to 509/512 thats a pretty good jump and will be much cheaper than another new cam! Looking forward to hearing from someone! Thanks NORT

 

I highly doubt (about 99.9% sure) you won't have any trouble with 1.6s on that cam.

The bigger concern is where the 1.6 rockers move the pushrod closer to the rocker stud, and some factory heads bind in the pushrod slots because of this.

You probably won't see an enourmous gain if any from the switch, maybe 5-10hp or so, the butt-dyno wouldn't setect it.

 

That much lift will probably cause the valve springs to bind also.

 

all the SBCs i've ever checked the valve to piston clearance isn't much of an issue untill .6 or so lift. i check mine with oiut a head gasket so that's another .040 i could add to the lift, but most of my engines are zero deck, or close to it. in short i don't think you'll have any problems.

------------------
ICON Motorsports
1st & 3rd
MM Black Diamond 538 F&AM

 

I installed an Isky roller specs of 217/225 @ .050 and .475/.495. I used Comp Cams 1.6 roller tip rockers for a corrected lift or .505/.525 on an otherwise stock 305 block and heads (1.84/1.5 valves). I upgraded the springs to Comp Cams Conical type -- so I wouldn't have to have the heads modified. I should mention I spent BIG BUCKS on a top line set of push rods but these were factory length. The setup worked very well and never had any hint of valve interference with the piston. For what it is worth this cam had an outstanding powerband and I never got tired of seeing it's redline.

RP.

------------------
'91 Formula Firebird G92,WS6,5-speed,3.42 a ton of fun to drive.

 

On my set of Vortec's I had to grind the pushrod holes closer to the studs for clearance with 1.6's. I also argee with Ede and check them without any head gaskets in place.