TravMsns

I just bought a new engine, here's the specs that the guy said were in it

Contains: *10:1 compression pistons *Edelbrock Performer RPM Heads *Edelbrock Performer RPM Cam *Edelbrock Performer RPM Air Gap Intake *Holley Fuel Pump *Crane Cams Gold Race Roller Rockers (1.5 ratio) *Crane Cams + .100" longer than stock push rods *Holley Fuel Pressure Gauge *Holley Adjustable Fuel Pressure Regulator *Aeroquip Fuel Lines and Fittings *Hooker Super Competition 1 3/4" Headers *Double Roller Timing Chain *Edelbrock Valve Covers and Breathers *Edelbrock 750 cfm carborator *Chrome Oil Pan *Chrome Timing Chain Cover *High Volume Oil Pump

what is the reasonig behind the .100" longer than stock push rods? will this affect anything if I want to do a cam swap? I want a little milder cam (XE268), will these longer push rods affect anything?

Top_Notch

Longer pushrods were used to retain proper valvetrain geometry. Really, it's no biggie, but if you swap the cam, check the valvetrain (which you have to do anyway).

JerryM

Higher lift cams will generally have a smaller diameter base circle on the lobes, as the lobe diameter is constrained by the cam bearing diameter. The rocker tip ideally would contact the center of the valve tip at all times, but practically speaking cannot. So you shoot for a little short of center to a little over center at 0 lash and full open. longer push rods are intended to make up for smaller lobe base circles.

Hope this helps.

Red73

TravMsns, Another Rochester NY member. There are a couple of us (Xracer, Johns77 and myself) that visit the C3 forum on a regular basis that are from the Rochester area.

The instructions for the Performer RPM Aluminum Heads for rocker arms says: Stock (stamped type) rockers will require +.100" longer than stock hardened pushrods to maintain proper geometry. The valve springs supplied will accommodate valve lifts up to .600", which is much higher than stock rocker arms will allow. Long slot stamped or roller rocker arms will be required if your camshaft has more than .480" lift. Non-stock rockers may not be legal; check local laws.

Note: 64cc heads #6089 may require +.100" longer than stock pushrods even with roller rocker arms. You must check retainer to rocker clearence.

Caution: Some Chevrolet V8 cylinder heads are factory equipped with "self-aligning" rocker arms. These rocker arms have a stamped recess on the valve tip end to guide the rocker arm on the valve stem which allows the rocker arm to guide the pushrod. Edelbrock cylinder heads are equiped with hardened pushrod guideplates. Therefore, you must use +.100" longer than stock hardened pushrods and non "self-aligning" rocker arms. Roller rocker arms may be used with stock length hardened pushrods. Printed 6/97.

Rod :cheers:


[Modified by Red73, 8:31 PM 12/17/2001]

Vetterodder

I use .100" longer pushrods because the instructions that came with my Edelbrock heads said I should.

TravMsns

Hey Red73, that's cool to know that there are a few others from Rochester. I have almost the same setup you have...see the signature. you didn't like the performer RPM cam huh? What didn't you like?

Red73

The guy that did my lower end recommended the EX268. I think the 268 has a smoother idle and better over all throttle response. It's to bad photopoint is having problems because you could have clicked below to see photos of my engine. Maybe they'll fix it soon or I'll find another place to host my photos. I also edited my first response if that helps.

If you go here you can see a shot of my engine on Xracer's website http://home.rochester.rr.com/thewebp...rs/Red73-1.jpg


[Modified by Red73, 8:43 PM 12/17/2001]