302 teardown - what is my engine telling me?

Hello everyone.

In preparation for building a GT40 in the summer, I started by purchasing a used 302 on eBay. I love the idea of tinkering with every nut and bolt, so decided to build an engine as well!

There was no mileage information on the engine - only that it had been shipped from the US. The engine code makes it a 1991 from a Ford Thunderbird. I could see a spider and dog-bones in the V of the engine so assumed it had roller lifters - a positive feature. I probably paid too much for it, but it was probably cheaper and easier than carry one home in a suitcase!

I have now started to strip the engine and I think it looks in good shape. I have never stripped an engine before so I am relying on books and YouTube. The oil looks thin and clear and the engine turns over easily.

I have taken the heads off and the top of all the pistons look the same - a bit black and crusty but having never done this before I am not sure if this is good or not. The gaskets are a sort of metal paper stamped with Ford, so assume they are original. However, closely examining the marks left by the gaskets almost suggests they were different left to right. I will dig them out of the bin and double check.

A look at the inside of the cumbustion chamber and the valves shows a very different story. One bank of the engine shows grey / white coloured valves with a pitted texture. The other bank shows brown / black looking valves except one which is a lot darker.

Having pulled the pistons and examined the bearings, all looks good - even wear and no scoring. I am not planning to reuse the heads - I hope someone might want to buy them for a stock rebuild. I am now puzzled as to what the heads are telling me, and this is where I humbly ask for your expertise.



  • IMG_20220122_154153966.jpg
    376.6 KB · Views: 322
Ford use the same gasket for both banks, since the gasket controls the flow amounts for each side one is fitted upside down in relation to the other bank, thats why they ae marked front rather than up or down. There should be a 'tag' on front outer corner of each.

Bill Kearley

The difference in color is probably the result of air/fuel ratio, not sure why in this case??? Have the heads checked for surface trueness and cracks and you should be good to go. New gaskets will be marked FRONT. Installed wrong will cause overheating in a bad way.
As Bill says looks like one bank was running rich and one lean to me.

you are aware being a 91 block that you’ll have to pass emissions requirements for IVA?3.5% CO2, 1200ppm I believe? If it goes past ‘92 then you need cats.

I would suggest selling that engine and getting a 1970’s block. When it comes to IVA It’ll be “visible smoke check only” and that will save a ton of aggro/expense.
They are out there.