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rockurrolla 01-21-2006 09:37 AM

push rod length
 
I have a 383 stroker with a .560 lift on the intake and .560 on the exhaust. The duration is 230*.What size push rod do I need? I'm using 1:5 ratio roller rockers. I've read some info. on using a pushrod length checker. It is confusing for an inexperienced mechanic.

DoubleVision 01-21-2006 09:43 AM

Majority of the small block chevy`s I`ve seen use the same push rod. You`ll need a aftermarket pushrod that`s heat treated. The comp magnum push rods should serve you fine. If you`re referring to lenth, that`s a different story, the lenth is different between the gen. 1 flat tappet blocks and the Gen. 1 roller cam blocks. The only reason you should need a different lenth pushrod is if the block or heads have been milled, and then it depends on how much was milled. There is a pushrod lenth checker that many of the cam companys sell, you`ll find them in Summit or Jegs.

onovakind67 01-21-2006 10:27 AM

Quote:

Originally Posted by rockurrolla
I have a 383 stroker with a .560 lift on the intake and .560 on the exhaust. The duration is 230*.What size push rod do I need? I'm using 1:5 ratio roller rockers. I've read some info. on using a pushrod length checker. It is confusing for an inexperienced mechanic.

A 230 cam with .560" lift looks like a roller cam, possibly the Comp 286HR. Is this correct? Is the block an original roller block?

trees 01-21-2006 05:37 PM

There is nothing magic about checking pushrod length. It is something you need to learn to do if you are going to build your own motors. To do this, I take a magic marker and blacken the end of the valve where the rocker arm rides. I adjust the valve and then rotate the motor until the valve goes through a complete cycle. I then remove the rocker arm and look to see how much of the marker has been wiped off and what part of the valve end is clean. When you have the correct pushrod length installed, this wiped area should be in the center of the valve. If it is not, repeat the process using the push rod checker until the pattern is back in the center, then measure the length of the checker and order that length push rod. If you do not have a mic big enough to accurately measure it, you can get close enough by standing the tool and a stock length rod perfectly straight on a level surface and use a feeler gage to measure the difference between the two and add or subtract . Or you can take the checker to your local machine shop and let them measure it for you. When I built my 383, I used Edelbrock Etech 200 heads and Competition Cams Pro Magnum roller rockers. I had to get new pushrods that were .25" shorter than stock (Yes, 1/4 inch!) Had I not checked there was a potential of destroying the valve train since the pattern center was on the edge of the valve stem!

Trees

IanRiordan 01-22-2006 05:09 AM

I use a Manley checker, it's cheap, quick and accurate. My current combo (flat tappet hydraulic) needs .135 o/length pushrods.

rockurrolla 01-22-2006 08:36 AM

small chevy 383 stroker
 
Quote:

Originally Posted by onovakind67
A 230 cam with .560" lift looks like a roller cam, possibly the Comp 286HR. Is this correct? Is the block an original roller block?

You're right about the cam(comp cams 286HR). It's an older block(non-roller) man, those lifters are expensive(retro-fit) I put Franklin heads on. My machinist put heavier springs to handle the .560 lift. It has an Eagle stroker rotating assembly with 6 in. rods.

onovakind67 01-22-2006 08:49 AM

Using the Comp retrofit hydraulic rollers will require a much shorter than stock pushrod because the lifter is taller. Stockers are about 7.8", HR pushrods are about 7.3".


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