will a 74.5 head fit on an 8/73 block?

slickrock · Dec 5, 2007

will a 74.5 (F.5) head fit on an 8/73 block?

I have an old time neighbor that has a bown head and I wanted to help him out. Is a 74.5 head a direct bolt on (no modifications) to an 8/73 block?

In other words, can I take a complete head (and all internal parts) off a 74.5 engine block and put it on to a 8/73 block?

rjcruiser · Dec 5, 2007

I believe it is....the only thing that could be different is the oiling. If they are both 1f engines, then yes. I believe that the '73 will have the oil coming up a copper tube from the bottom of the block up through the head to the valve train assembly. Not sure if the '74.5 had the same oiling system or if it had the 2f oiling system. If the 74.5 has the oil tube coming up through the head, you should be golden.

Just be sure that you get clearance from that copper oil tube when you take the head off and have someone help guide it up through the new head as you put it back on. You don't want to pinch or crush the oil tube. Don't ask how I know

slickrock · Dec 5, 2007

Thanks for the response. Does anyone know for sure if the 74.5 has the F oiling system since it is one of the cross over engines?
I remember something about better oiling with the 74.5.

I do know that the 74.5 has the oil filter on the opposite side of the later 73 engine.

Degnol · Dec 5, 2007

No, it oils like a 2F. Won't work. Not easily at least. :frown:

Ed

IDave · Dec 5, 2007

I think as long as you used the split rocker armshaft setup from the earlier F engine, you can run the copper tube up and attach it to the banjo fitting just fine. The hole for the tube is there on the F.5 head.

You wouldn't have the advantage of the later oiling, but it would work just like our older Fs.

Unless there's a problem with the F.5 and the older F pistons, I don't see why it wouldn't work.

slickrock · Dec 5, 2007

IDave said:
I think as long as you used the split rocker armshaft setup from the earlier F engine, you can run the copper tube up and attach it to the banjo fitting just fine. The hole for the tube is there on the F.5 head.

You wouldn't have the advantage of the later oiling, but it would work just like our older Fs.

Unless there's a problem with the F.5 and the older F pistons, I don't see why it wouldn't work.

Here is the F.5 head I have and it does have the oil for the oil tube.

and the oil shaft in the F head:

I am confused on the split rocker armshaft setup. What would I have to transfer over from the F head, besides the copper tube and banjo fitting) to make it work? I didn't know the rocer arms were different.
This is the SOR picture from mid 60 to late 80s. Can you point out the split rocker armshaft?

The head on the F.5 has been rebuilt in the very receint past so I want to use it when I pull my F engine to replace the seals. Any specific direction to take or how to information would be great. Thanks!

IDave · Dec 5, 2007

Number 8 (rocker arm shaft) (x2) and the banjo fitting, as well as the copper tube are all that is visibly different on the setup, and all you would have to transfer over. F.5 and 2F rocker arm shafts are a single piece (see both your and my F.5 pictures). Your older F will have the two piece/split shaft and banjo fitting.

You could, as I have done, pick the best rocker arms (the bushings where they ride the rocker arm shaft get worn), disassemble and reassemble, and clean up (I used a drum sander) the rocker arm tips where they hit the top of the valves (which will make your valve lash measuring easier), and clean out the oil holes in the arms as well.

Or, you could just take the assembly off the old head and stick it on the F.5 head.

slickrock · Dec 5, 2007

Nice. For most basic transfer I need to take off the brass tube and banjo fitting for the oil pick up, and the 2 piece rocker arm (numbers 8 on the above picture) from the old F engine. If that is it, that's simple enough.

I will also take the best rocker arms from both engines (#s 20) bushings (#s 19).

Thank you for all your help. looks like my vacation I am taking during Christmas has a project to fill.

3_puppies · Dec 5, 2007

make sure the block is true when the head is off.

IDave · Dec 5, 2007

3_puppies said:
make sure the block is true when the head is off.

Has anyone ever seen an F block that's not true? I know the heads warp, but...?

rjcruiser · Dec 6, 2007

rjcruiser said:
Just be sure that you get clearance from that copper oil tube when you take the head off and have someone help guide it up through the new head as you put it back on. You don't want to pinch or crush the oil tube. Don't ask how I know

And don't forget this

It will be easy to do when you're trying to pull the heavy heavy head off of the block by yourself.

slickrock · Dec 6, 2007

sounds good. thanks!

slickrock · Dec 18, 2007

Bad news, if I use the f.5 head on an f block, I will loose a bunch of compression. The f.5 has rounded heads while the f has flat. I would have to machine the f.5 heads down flat.

will a 74.5 head fit on an 8/73 block?

More options

slickrock

rjcruiser

slickrock

Degnol

IDave

slickrock

IDave

slickrock

3_puppies

IDave

rjcruiser

slickrock

slickrock

Similar threads

Users who are viewing this thread

Share this page

Connect with us

will a 74.5 head fit on an 8/73 block?

Similar threads

Users who are viewing this thread

Log in

Share this page