While inspecting my 292 head I found that it had a patch up job that probally would not last. I have a 272 that could be a donor, but one thing I found out quick is that the intake valves are quite alot larger then on the 292. I do have a chance to aquire another head with smaller sized valves. What would the difference be on power and/or fuel. Should I put the head with bigger or smaller intake valves on?

 

A lot of different ways to look at this one.

1) If you just want to get it running & aren't too fussy, use the 272 head (assuming it's in good shape, of course). Not my choice to use different heads, but it's been done before. Note that for your two engines this is possible, but in other cases it may not be (for example, a Boss 302 head won't go on, say, a 221 small block Ford; it will physically bolt on, but the larger valves would hit the block.)

2) On the other hand, from an engine builder's point of view, it's best to make each cylinder's output as close to the others as possible, both for power & efficiency. There are a great many techniques & philosophies on how to do this, but, obviously, you would use the same size parts in each.

3) So far as power/mileage, you may not notice a whole lot either way. Tough to say.

4) As long as you are going to this amount of work, it might be worthwhile to take BOTH the 272 heads, freshen them, and use that pair. Assuming you don't want to do that/can't, then I'd get the other head with the smaller valves, if it is similar to your existing 292 head- there are three different intake valve sizes, & a lot of different castings.

5) Depending on what pieces you have, you might possibly have some issues with port matching. Keep an eye out so you don't end up with a vacuum leak.

Clear as mud?

 

Regarding Homespun's point #1. When I obtained my 292 from a junkyard, it came from an F-350. One head was an ECZ-C, and the other was a 113. The 113 head did have the same 1.78 in. intakes as the C however. Apparently the heads worked well enough to drive the truck to death. The cleanup of the bore required .080 overbore, and the crank had to go to .050 undersize main bearings.
Like him I'm not necessarily suggesting you use two different heads, but if you did, chances are you wouldnt notice it if the truck is used as it was intended.

 

If that 272 is from a 57 it may have the G heads. You may want to check the casting #s you can find them at www.ford-y-block.com. I ran both the large valve and small valve heads. Large valve had more top end power. Smaller valve had very good low end power but lacked on the hiway.

 

1960-64 heads reverted to the peanut size 1954 valves which were 1.64".
The imbalance between different spec heads wont be that noticable on a stock street driven truck; heck even Ford was sloppy on their chamber tolerances on any one head.
How about posting some casting ID's?

 

I ran both the large valve and small valve heads.QUOTE]

Is there a majior fuel consumption difference? Which heads are you running?

Thanks for all the help it is greatly appreciated.