You didn't mention what era or brand of cars you are planning to do but these should give a general idea. Here are a few shots of some Ford engines I found while wandering about in the Wood Bros' garage and the Roush Museum near Charlotte last fall. I'm not sure when they started using the new valve covers. I don't know if there is a source for these.
These two are from the Wood Bros
![](http://farm4.static.flickr.com/3612/3332666719_fe70a75bfa.jpg)
![](http://farm4.static.flickr.com/3408/3332666741_aa3bf7fe06.jpg)
This is from Jamie's wrecked Busch car on display at the Roush museum. Be aware there may be a few dents, creases and scrapes that aren't normally part of a normal engine.
![](http://farm4.static.flickr.com/3641/3366567150_2f0356e8fc.jpg)
This is a NASCAR engine on display at the Roush museum. You can see the alternator (top), distributor, water pump (center), and the oil pump (bottom) and associated drive belts.
![](http://farm4.static.flickr.com/3603/3365743343_08dda052c9.jpg)
Another view of the Roush display engine.
![](http://farm4.static.flickr.com/3474/3366567672_1aa3d6da9b.jpg)
There are some structural differences such as front-mounted distributors and right side oil pump on the Ford engines. I'm not sure about the latest Chevy, Dodge and Toyota engines. Hope this helps.