1970 351 Cleveland – Ford Mustang Mach 1 – Engine Rebuild

My brother has gotten to the point of rebuilding the engine of his 1970 Ford Mustang Mach 1. The engine is a 1970 351 Cleveland that was built on Aug 10, 1969. That’s a pretty long time ago.

I gave Jeff a call yesterday and he told me about what he was doing. I got excited, because it reminded me of the days when I was cool…rebuilding engines of my own. I am partial to Chevy small blocks, but I guess Fords are ok too. I remember every detail of rebuilding all my engines. It is quite interesting, because you get to see how everything works and how different parts have different effects on performance.

So, here is what he told me. He pulled the engine a while back. He recently took the heads off to measure the bore of the cylinders. This is important because if the bore of the cylinders is too large, that means the cylinders are worn and they need to be bored out. You hear this kind of talk a lot among 16 year olds that ride 2-stroke dirt bikes. They are always talking about “boring out” their engines. I know this, because I was one of them (16 year old, that is). Remember, if measuring the diameter of the cylinders, make sure you take the measurement more than a half-inch down, inside the cylinders. The top half-inch of the cylinder doesn’t get touched by the piston rings…the part that wears the cylinder.

Anyway, there is another important measurement that Jeff needed to take, and that was the diameter of the bottom of the cylinder compared to the top of the same cylinder. This is a measurement to see if the cylinders are “tapered,” meaning, one part of the cylinder is worn more than the other. Since this is kind of a tough measurement to take, Jeff brought the engine down to his local machine shop. He is getting a bunch of work done to the engine down there. Here is a list of what they are going to do:

– Measure the cylinder diameters (like I described above)
– If ok, (which they are…it was already done) hone the cylinders the proper way for the type of rings that will be installed
– Clean the outside of the engine block and heads
– Flush the inside of the engine block and install new freeze out plugs
– Install new camshaft bearings
– Give the cylinder heads a valve job
– Install hardened valve seats to allow for unleaded gasoline

I am probably missing something. I forget a lot in these later years of life. In any event, this is all the stuff that requires professional attention. Jeff can take care of the other stuff, like installing the camshaft, the timing set, etc… All that takes in a steady hand and a torque wrench. I am sure the engine will come out very nicely. Jeff is currently looking for genuine Ford colored engine paint, to get the color just right. This is important with an engine like this because it is going to be restored to original specs. With a “matching numbers” car like this, you can’t make mistakes like painting the engine the wrong color.

Here are some “before” photos of the engine:

Jeff is also sending the carburetor out to Pony Carburetors for a total rebuild. Apparently, their rebuild techniques take a lot of natural issues out of the carburetor. I am sure there will be a post dedicated to that alone.