Engine hasn't been rotated since disassembly and the rotor's position was marked prior to pulling the dist.

What do I need to consider when replacing the heads? My thought was that tightening the rockers would return the valves to their proper position by the push rods/cam lobes. Is there a need to rotate to TDC? Can I just tighten up, put the dist in with the rotor to the mark and go?

 

The 85 will be stamped steel and the 78 might have cast iron rocker arms.

They used slightly different pushrod lengths (just enough to maybe screw up your lifter preload pretty good)

What's the history of the 85 heads, rebuilt or just taken off of another engine?

You're about 1 decade off on the pedestal mount rockers ,,,,,,,,,,,,,1978

Since the engine in his 1978 boat may be a 1977 as they commonly weren't necessarily the same as the boat year, that why I asked him the same question about the rockers

KENO, I usually live my life being a "decade off".... 

I didn't think lash had to be set with hydraulic lifters. I've been imagining 19ft/lbs was the requirement.

Not really 

Here's a link to an old thread with some good info

http://www.correctcraftfan.com/forum/forum_posts.asp?TID=40605&title=valve-lash-adjustment" rel="nofollow - link

So do you have the same style rocker arms on both the newer 85 heads and the older 78 heads?

What do you have for pushrods?

If needed, new stock pushrods to go with your 85 stamped rockers are cheap

They're .035 inches longer than your 78 pushrods

8.185 inches vs 8.15 inches

Those words should be saying "This won't be bad at all" 

It kept coming out the same..................035 difference 

So what's your "old math" telling you?

In the above example if you had .030 instead of .040 inches and used the old pushrods, you'd have a gap of .005 inches between the pushrod and lifter and it'd be banging and clanging like an old singer sewing machine.

Knowing the guy you got the heads from, he PM'd me that they were stock, no machining of any kind and low hours and good running when removed.

I'd bolt them on and use some new 8.185 pushrods to give you a much better chance of being near the middle of the spec.

Somebody might say that you're mixing and matching new parts and old, in this case new pushrods and old rocker arms and lifters. They should wear together with no problems.

Most everybody here on CCF who's replaced their original heads on say an 80's 351w with gt40P's has reused their old correct length pushrods without giving it a second thought and their pushrods and rockers wore to match each other just fine. They might have needed shims that were mentioned earlier in the thread if the heads were milled down quite a bit at the machine shop, but yours have had no machining.

If they used the original rockers, then the rockers and the valve stems would have to wear to match each other.

Kind of a vicious cycle, something has to wear to match the old and new parts unless you're replacing everything.

The earlier link to an old thread with the "Shep72 method" works good for showing that your preload falls in the recommended range.

Keep in mind that there are more sophisticated methods of checking preload but this works good

I've done the same swap on a 70's engine with 80's heads and pushrods with no problems and lots of running hours later it's still doing good.

I hope that all this makes sense to you 

And thanks for the info from that unnamed character you got the heads from.

http://www.rockauto.com/en/catalog/ford,1985,bronco,5.8l+351cid+v8,1105838,engine,push+rod,5648" rel="nofollow - link

They're 8 182 inches not the 8.185 that I said numerous times.

PS i don't think you've verified what your 78 had for rockers yet, the stamped steel or the cast iron.

If they're stamped steel, you could reuse the old pushrods.

You can find directions here on CCF or just ask if you're having trouble.

Around 2002 I rebuilt an engine for my son's truck, we bought all our parts but at that time there was a nationwide lifter shortage, the only lifters available at that time were Moresa lifters out of Mexico, shops I know told me not to run Moresa back then because they were seeing 15-20% failures with them.  ( maybe Moresa lifters are a quality part today, I have no idea but in 2002 they were trouble ) I installed the brand new camshaft in that freshly rebuilt engine with all 16 of the old factory stock lifters that had 120,000 miles on them, I took them apart and cleaned them well before install then I broke the cam in carefully on those used lifters and that engine ran great many years till we sold the truck.  The lifter is much more critical and prone to failure than the push rod and rocker arm.  It was the wrong thing to do I know that, but had no choice at that time.  Parts can be re used if they are in good condition.  Machine Shops do it all the time, but I have never seen a machine shop re use any lifters so don't follow my lead on that one.

No you are not... good solid advice here....I re-built my first small block when I was 16, back before the interweb and the access to unlimited information, I used an old "Motors Services" manual in an old shed... the engine ran just fine and was abused severely by 16 year old me and the 4 speed behind it... been doing engine work for the (44) years since

Swapping heads is more about looking for odd wear patterns on the parts (if used), and making sure the lash is done correctly  and within spec. Hydraulic lifters are more forgiving on the subject of lash, but it still needs to be within spec.

Good Luck.... Tom