94 or newer 351W has roller cam. Don’t waste time or money on non-roller blocks

Ditto on 5.0 blocks. Roller cam from 1985 foxbody-2001 Explorer

I have purchased complete Explorer 97 engines with GT40 heads and GT40 intake for as little as $100, but those days seem to be long gone.

The newer 5.0 blocks are probably limited to a 0.030" overbore unless you sonic check and verify it can safely go more.  Older blocks may have more meat in them, but the lack of a roller cam for me is a non starter given the cost of link bar lifters vs. OEM style. 

A lot was made years ago about the Mexican blocks (allegedly higher nickle content), but what's it worth?  A factory block is going to be limited to about 500-600HP.  After that you'd be better off just buying an aftermarket block designed for big power. 
 

On my 351W I built years ago, I used a 1969 block which is 0.023" shorter deck height than 72(?) and newer.  I used pistons designed for the taller block, so my pistons actually stuck out of the deck 0.005".  This made for much greater squish of the fuel charge and I am convinced it ran better and was less likely to ping.  I used Edelbrock 60cc heads and a gasket with 0.041" compressed thickness, which allowed for actual piston/head clearance of 0.036"

Thanks guys for sharing.

I have read problems about both roller and non-roller blocks.

The failures of camshafts and lifters for both styles seem to still occur.

I am not completely convinced that flat tappets are bad.

MS wrote:

Nos681 wrote:

Thanks guys for sharing.

I have read problems about both roller and non-roller blocks.

The failures of camshafts and lifters for both styles seem to still occur.

I am not completely convinced that flat tappets are bad.

Go ahead and build one. You will be convinced soon. Or, maybe you will get lucky. But, since starting from scratch, why not choose the less failure-prone option?

Let's examine this for a minute.  Flat tappets create an extreme pressure situation at the lifter to cam interface.  This requires ZDDP or some other oil additive to prevent catastrophic failure.  Roller cams have no such issue.  Flat tappet cams are a balancing act between being flexible enough not to snap under spring pressure and hard enough not to go away from that pressure.  Roller cams have no such issue.  By rollerizing the valvetrain you eliminate about 50% of the friction in an engine, and its associated heat. 

Then there's power.  Roller cams make more power under the curve because they can use much more aggressive opening and closing ramps without fear of the edge of the lifter digging in to the cam lobe.  Even if all the cam specs are the same the roller engine will be more responsive and make more power right where you want it (off idle, part throttle, transition throttle, etc.). 

As for failures, there are millions of roller engines with 200k or more that would indicate they don't fail very often.  Most flat tappet engines are lucky to go 100k.  Yes, part of that is that most rollers are EFI, BUT the cams, lifters, etc. still LAST that long without failure when flat tappet cams are being tossed at rebuild time in half that mileage.  The failures I've seen in roller engines were the result of cheap lifters.  I've seen flat tappets fail on initial engine start up.
 

I agree, Rudi

Oils have changed. Metals used in the lifters and cams are obviously not the same as they once were.

If using new cam and lifters, my thinking is the only hope of any success is to use a billet steel roller cam with roller lifters. 

The real question with that is whether the $79 Ford replacement roller lifters from ebay are just as good as the R version of the Ford Racing lifters.

I have been tempted to build up a 5.0 with all the absolutely bottom feeder, lowest price ebay parts just to see how it worked out. I am betting you could not tell the difference on a car used for just normal driving.

Nothing to add other than if you want a 351w *roller* block look for the F4TE casting number down by the starter

I’d bet large on the fact Ford built their own lifters in the 60’s, these days prolly not. Everything out of China in those days was made from recycled soup cans, stuff still had Campbells lithographed on the back side.

I’m 100% sure GM did make their own lifters at that time cause we had a big GM engine manufacturing plant next city over and an acquaintance who worked there showed me a pail full of them he lifted, pun intended.

It’s a crying shame the little guys in the hobby , whose pockets are not bottomless, have to suffer because of profit driven greed.
Rant over.🤬

Nos681 wrote:

Planned to use the roller block I have.

I was looking at a stripped down 74 block at local machine shop and wondered about strength and bore size limits.

It was .030 or .040 already.
I was looking at the thickness and wondered if they can go further?

Maybe, maybe not.  The only way to be sure is to sonic check it.  I've seen some older FE engines that could be bored 0.125" over (not a typo).  We used to bore BBCs 0.060" over all the time and think nothing of it.  It just depends on how thick the cylinder walls are, AND if there's any appreciable core shift. 

You also have to remember that going from say 0.030" to 0.040" is only 0.010" more, and that means its only taking 0.005" off each side of the bore.  That's very, very little to try and clean anything up or fix taper, etc.  Years ago a machine shop operator I knew told be that a solid foundation for a stock block race engine was a seasoned block that had been in a tow truck for 100k miles bored 0.030" over.  The mileage and the use themocycled the block enough that it was stable, and the 0.030" over bore was enough to give you perfectly straight and round cylinders for best ring seal and max power.  He said it was false economy to try and only go 0.020" initially.  Now, on subsequent rebuilds/freshenings you might be able to get away with less, in part because the block is now stable, but just remember how little that 0.010" over bore removes.  Trying to save the block by boring it the bare minimum and risking less than stellar ring seal is simply not worth it.  Also, how many miles are you realistically going to put on it?  I usually target 100k life expectancy, but honestly if most of my fun car engines lasted half that its doubtful that I would ever end up rebuilding them in my lifetime anyway. 

Toploader wrote:

My engine will need a rebuild in the coming years and was hoping to just rebuild the original engine, but this conversation about lifter failures is concerning.

Growing up my dad and uncle and a lot of their friends all had Corvettes, Chevelles, etc.  Nothing was mundane.  I'm talking big block L88s, LS6s, etc.  Even in the '80s and '90s when the values of those cars wasn't insane everyone pulled the original engine, mothballed it, and dropped in an engine that was basically the same, but not numbers matching.  That way if they blew it up it didn't devalue the car when it was time to sell it.  If I were you, I'd build a decent 5.0 based engine to run around on and keep the original. 
 

I did a Gargle search and was told  Top Line Johnson MAKES their own hydraulic flat tappet lifters here in the good old USA and they stand behind them with a guarantee !
Howard offers a  'somewhat guarantee' on their lifters and camshafts.
Just a FYI..........for flat tappet guyz
6sal6

Stick with a roller block. I imagine it you were dead set flat tappet lifters, then they would still fit in the block. Any grooves around the lifter could bleed off oil pressure due to the alignment with the oil passages.

The only thing that changed more than Ford part numbers is the core shift on the blocks. I had a .060 over FE with good thickness on all the cylinders and it didn't overheat. I bought another .030 block cause the cylinders looked good and their wasn't enough material left to go .040. The only sure fire method to knowing how much a block can be bored is a sonic test. I don't know that I would trust the guys if he had a sheet on one or not. Depends on who the person is and how well I know them. Best to have them meet at the machine shop and pay for it yourself if they won't split the cost.