Do I need new push rods? pcfixer thinks I should get hardened push rods. My plans are

Comp Cam 20-604-9
HD EQ Iron heads
Harland Sharp 1.6 roller rockers

I asked the people I am getting the heads off of and they said I can use stock length rods. Anybody know anything about this kinda stuff?

 

The only reason I suggested to get new chromemoly pushrods is because the harland sharp roller rockers dont use valve guides. It isn't completely necessary I guess, but rather a good suggestion. If your going new everywhere else, (cam, head, roller rocker, etc...) mise well finish it up with one last set of parts. Who knows, pull your old set out and roll them agains a piece of glass. If they dont roll freely, it is probably cheap insurance to get a new set anyway. Look up "deflection"

 

its all good brother. I also wanna know people's opnion on the size issue

 

+1

they are less than 100bucks.
http://www.jegs.com/i/Edelbrock/350/9638/10002/-1
http://www.jegs.com/i/Comp+Cams/249/7632-16/10002/-1


alot of people i know replace the lifters at the same time as the cam, because of the groves that maybe the lifters.
http://store.summitracing.com/partde...2&autoview=sku

 

I actually have them lifters in my cart

 

The big advantage of choosing stock replacement heads is the ability to go back with the stock valvetrain (as long as it checks out). People like to assume that the aftermarket is always better than stock. Not the case. For example, I reused my stock lifters because after clean-up and inspection, they were much better (heavier duty, IMO) than the $140 aftermarket lifter set I bought to replace them. Factory push rods (again, in my experience) are pretty bullet proof. It usually takes something like a piston slapping a valve to bend one. If you're going with high spring pressures and valve lifts, then that's another story. Also, I don't see any problem with reusing the factory rockers in a street engine because they have that very broad, load bearing surface that roller rockers do not, although the rollers are probably more accurate when it comes to a consistent ratio across all the valves. Of course it all boils down to expectations and what you're willing to spend.

 

roller rockers will "free up" some ponies due to the roller tip and the needle point bearings vs the stock rockers. If they're aluminum you get a slight weight savings on both the valvetrain and overall weight.

If you go the 1.7 RR route, you'll also get added lift (.459 vs stock .432 lift) Then you'll really enjoy the new power. This was my favorite mod so far.

If you're going to be hammering on it a lot (street racing, drag racing) Then I would recommend the hardened pushrods, otherwise you can reuse the stockers.

 

But even with his cam he is planning to get, would you still recomend the 1.7's ?

 

what's the lift and duration on that cam? I'm lazy.

If you keep the total lift under about .540 ( not just the cam lift, but cam and rockers) and the duration is close to stock, the 1.7's should still be usable on a less aggressive cam. Some feel that the slight geometry change increases strain on the valvetrain. Others have reported no problems at all. The higher the cam's lift, the more the strain, so at some point going to 1.6 is probably a good idea. I can't tell you for sure where that magical line is though. Another big advantage of the 1.6 rockers is that you don't have to risk a miscalculation on the lift as the advertised lift of a cam is based off of the 1.6:1 ratio.

Regardless, you should always check for adequate piston-to-valve clearance. The 318 has slightly less P/V clearance than the 360 as the 360 incorporates a slight "soap dish" indentation into the piston top whereas the 318 is a flat top piston. An easy way to check is to place modeling clay on top the piston and put the head back on and turn over the engine by hand a few times. Then measure the thickness of the clay in the center of the valve depressions to get the P/V.

 

http://www.compcams.com/Cam_Specs/Ca...?csid=664&sb=0

theres all the cam details. It says to use 1.6's. I'm not gona be street racing or anything but i do beat on my stuff with normal everyday driving once in a while. I guess for the money I'm spending I should upgrade them to be safe