Tach inst. cluster, rocker arms, comp. ratio

[jarclay]

Gentlemen,

1. I purchased a tach speedo cluster for my 71 510 2 dr. Before I tear into the project is this a hard swap to do? And are there already wires there for the tach. or do I need to run some ?

2. I bought a head that looks almost ready to go but it has no rocker arms. I bought a cheap set from a friend but they have a grove cut from wear with the cam.. are the pads that come in contact with the cam replaceable ? Or are new rocker arms available?

3. What do you think the comp. ratio would be with an L20 block and a A87 peanut head be with...

a. flat top pistons ?

b. stock dished pistons ?

As always your help and experience is greatly appreciated.

James B.

Edited September 8, 2009 by jarclay

[datzenmike]

2/ Do not use worn ones they will only grind up the cam. Good used ones can be carefully wet sanded with 800-1000 grit paper in the sink to condition them or buy new ones. Once used they should never be mixed up but labeled and returned to their original place to preserve their wear pattern on that cam lobe.

 

3/ Competition ratio transmission? This is a term loosely thrown around for certain stock transmissions but unless ordered through Nissan, with proof, there is little to distinguish it from tens of thousands of transmissions out there. What is competition anyway? Close ratio gears? Or maybe a 5 speed without overdrive? If you are in stop and go traffic you don't want a close ratio. For road racing with no or few stops then yes a close or ultra close ratio would be fine. If you have a competition tranny post a picture of it.

 

Stock L20B with A-87 closed head would be around 8.9 compression and should still run on reg gas. The difference in power over an open head would be just noticeable to not noticeable. Flat top pistons will ping and need premium fuel all the time which could be a pain.

[jarclay]

Thanks mucho mucho for the info...