302 engine block wear?

Excuse the newbie question.... I've been lurking in the forum for a bit, keen to build a GT40 but trying to learn what I can first of all.
I like the idea of building an engine to start with. I've seen a 1974 engine block for sale (which I understand would be easier come emission time - no visible smoke etc...).

However, my question is:
How do you know if an engine block is worn or OK?
I guess you can have it bored out? but if it's been bored out before can you only go to 30thou max and then that's the end of the block?
Do engine blocks wear out? Crack? or is it all the other bits that wear out and an engine block only gets worn by rust in the cylinders etc.?

This is the block I was looking at:

Any thoughts? Is it too risky buying a block off ebay with no warranty?

Also, I know how long is a piece of string... but generally... how much money would you expect all the other bits to cost for me to build that engine?
I would be buying the block to learn more about the engine build, but I don't want it to cost me 3 times the price of just buying a crate engine at the end of the day...

Thanks in advance.


Mortified GT
The easiest is to just buy a crate engine. Buiding from scratch, doing all the research in matching parts that will actually work and all the hours mskes it very costly in the end.
Building the engine before the car..... you will to have to store it dry for a couple of years the time you build your car, then strip to see of no humidity got inside the cylinders .... because their is always one valve open on the engine... and humidity will get in ...
As long as the engine has oil.in it and its turned over shouldn't be a problem.ask about bore size as if I recall 302 can go 40.thou over .if not machine and sleeve.

David Garton

I would worry about the deck. Seems very rusty and pitted on toward the back of the block around number four cylinder. You could have it decked for a fresh mating surface. It has a late 1975 date code. (5J24). Some machine work will surpass the cost of a crate motor. What your building is not date code sensitive so I would also recommend going with new technology long block crate motor.

Mike Pass

If you plan to put the car through IVA then it makes a lot of sense to use a pre'75 block as the emissions requirement then is " no visible smoke".
The standard bore is 4.000" Most common overbore is plus 30thou or 4.030".
The one I had was crack tested, dipped and cleaned, bored and honed to +30th, mains line honed, decked true to mains, machined for one piece oil seal, screw in oil gallery plugs, new cam bearings, new core plugs, notched for 347ci., paint. Cost £800 4 years ago.
Crate motors can be built for you on a pre '75 base by Real Steel in UK or lots in USA. The block you refer to is a quite expensive even though good standard blocks are getting hard to find in the UK.
As Paul says if you are building a car the usual time is 3 years+ so if you find a good block at a good price oil it thoroughly, bag it and stash it away. Pick up parts as you find them as you build and store them away or you can wait and get your block built up when you are ready for it.
Join the GT40 Enthusiasts Club as there will be a group near you and members get to know about cars and parts often before they get advertised.
Decide early on what you want it to do as this will determine the spec and the cost. Have the engine set up and run in on the dyno - the best money you can spend.
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Doc Watson

Lifetime Supporter
...or you could store it like this....