The easiest and smallest tachometer to install is a little self contained unit from http://www.tinytach.com/ It simply gets one wire grounded, and one wire wraps around a plug wire a few times. Then double stick tape to the dash. Mine cost about $35 a few years ago.

I also have a 235, and while driving around the country (8,000 miles) I kept it around 2400 to 2500 rpm max.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-