1970 f250 390 build

[blykins]

Did you mean cam on the big side for the factory headed engine?

If you were never gonna switch heads, then yes, you'd need a little larger cam than usual to feed the larger displacement with factory head flow. 

However, if you're planning on upgrading the heads, the "good" heads will need a lot less duration to get to the same point.  So, you'd need a smaller cam than what you'd think. 

From the testing I've done, you gain around 100 rpm of peak hp rpm per 10 cfm that the head flow goes up.  If you go from something like a C8AE-H head that flows around 220cfm up to a 330 cfm Trick Flow head, you can see why the cam change would be necessary.

If you stick a set of C8AE-H heads on a 445 short block, with plans to upgrade to TFS heads down the road, I would cam the engine for the TFS heads. 

As a rough example to try and illustrate the point better, back in the day when we were using Edelbrock heads, I would get about 475-500hp with a 445 and an Edelbrock head with a good valve job, bowl blend, 11/32" valves, etc.  I'd use a 235 @ .050" duration camshaft to get there.  When the TFS heads came out, I found that I could make 540-550 hp with them, but use a smaller camshaft at around 230 @ .050" duration.  Those Edelbrock heads were about 280-290 cfm, where as the TFS heads sit at around 330.  So you could see how much more camshaft you would need to try to get a 445 to work decently with a C8 factory head.  As a matter of fact, you'd probably never really be able to add enough camshaft to get them to make horsepower and you could end up with something that didn't have bottom end or top end either one.  You'd end up with a huge cam and then when you swapped heads to the TFS heads, you'd end up with something that would be making a ton more horsepower at a much higher rpm than what would be suitable for your application. 

Hope that makes more sense.

[nick c]

That's really interesting.  I guess the overly simplified analogy would essentially be that as airflow improves, the less duration is needed to make power.  Thanks, for taking the time to explain that Brent.       

[blykins]

That's really interesting.  I guess the overly simplified analogy would essentially be that as airflow improves, the less duration is needed to make power.  Thanks, for taking the time to explain that Brent.       

Yeah, that's a better explanation than my rambling. 

On some of my 347-363 SBF stuff with AFR heads, they will peak at 6200 with just a 219° @ .050" cam.  The heads make all the difference.

[nick c]

Question about purchasing complete internally balanced rotating assemblies.  Are the matching components stamped or otherwise marked?  Do the wrist pin/rod/pistons come assembled?  Wondering how the end user knows which components go where. 

When it comes to machine the block are the following what you'd ask the machine shop to perform:

Clean block
sonic check/magnaflux
Bore/hone cylinders (with torque plate?)
Square deck block
align hone main bearing caps
Cam bearing install

I have two candidate blocks, one is 4.050" bore the other is 4.080".  Is there a reason to use the 4.080" block?  Is it better to perform oiling system modifications prior to the machine shop work?

[blykins]

Question about purchasing complete internally balanced rotating assemblies.  Are the matching components stamped or otherwise marked?  Do the wrist pin/rod/pistons come assembled?  Wondering how the end user knows which components go where. 

When it comes to machine the block are the following what you'd ask the machine shop to perform:

Clean block
sonic check/magnaflux
Bore/hone cylinders (with torque plate?)
Square deck block
align hone main bearing caps
Cam bearing install

I have two candidate blocks, one is 4.050" bore the other is 4.080".  Is there a reason to use the 4.080" block?  Is it better to perform oiling system modifications prior to the machine shop work?

The end user will know one way or the other.  When you buy an internally balanced assembly, the seller will advise on what to do.  Some guys will grind material off to weight balance everything.  Some guys will mix and match parts/weights in order to keep from having to grind.  Pistons are not hung on the rods. 

You can use the 4.080" block if it is in good shape.  A good shop will sonic it before they do any work. 

For stuff to do, I'd say:

*Bake/tumble
*Pressure test/magnaflux
*Bore & hone with torque plates
*Square decks
*Align hone with fasteners you're going to use
*Install cam bearings

[Urgefor]

Most importantly with the machine work, know for sure and without any doubts the shop knows what they are doing with a FE block.

In the past few years, with older machinists retiring from the shops in my area, I've had a few "I almost got what I asked for" and zero "I got exactly what I asked for" experiences with work done on a couple FE blocks.  That is even after making a best effort before hand to ensure the shop could do what I wanted.  Even though the answers I got were "yes", in hindsight, they were obviously blowing smoke to get some business.

"Yes we have torque plates for that block" (they didn't) and "Yes we are familiar with FE blocks" (rear cam bearing plug installed backwards) are just a couple examples.

The most frustrating was my experience with wanting to have the cylinder work done with a torque plate.  They told me they had a torque plate (as noted above and yes, I called before sending the block to them to verify), I sent along the ARP head studs and a printed list of exactly what I wanted done to the block.  When I say printed, I mean typed in a word processer with nice large easy to read font and printed on paper.  I figured that would alleviate any issues with not being able to read someone else's handwriting.  When I got the block back and the ARP head studs were still in their original packaging and untouched, I immediately called to inquire why they weren't used with the torque plate as per the instructions I sent.  "We don't have a torque plate for FE blocks" was the response.....   *sigh*

Anyway, I think you get the idea.   

[My427stang]

Keep in mind, header flanges are different for aftermarket heads and the truck iron. 

Some can be drilled or slotted to allow the gasket and port to be aligned and seal, some cannot.  I have a stroker in my own truck and I decided to port the iron.  Nowhere near the performance of TFS, but my headers were ceramic coated and fit well. 490HP @5000 with an almost too mild hydraulic flat tappet, would be deep into the 500s with the TFS

If you have the headers already, buy a pair of gaskets for a CJ car and see if there is room to mover the bolt holes around.  Unfortunately, I do not think anyone makes the correct header if it's a 4x4 anymore, FPA used to but stopped making 4x4 headers

[HarleyJack17]

All I can add to the header deal is Hedman 4x4 Truck Headers 89120 fit BBM heads. The difference is very small...like 1/16".  It was not perfect but far from justifying anything custom.
There may be an old post on here when I build my motor and laid it all out. I have it on paper in my build notes somewhere. I had the heads on the bench and headers off.  I did a full layout to make sure I did not need to buy custom flanges/custom stuff. They fit fine and fit in the truck as well....very minor adjustment on the passenger side to a tube where the shackle comes into play, but not much more than from the old D2 heads and stock 360.  Almost all budget friendly headers on the old Highboys require some minor "adjusting".  Again, that is BBM and your milage may vary with TFS.

[nick c]

Question:  Can hydraulic roller lifters like the Morel's be reused following a cam swap?  Or do they 'wear in' to the cam lobes over time and need to be replaced with any cam change?

Or is that guidance more appropriate to the flat tappets and solid rollers?

[jayb]

Any roller lifter (solid or hydraulic) can be re-used on a new cam without a break-in period.  Flat tappet lifters need to be broken in to a specific cam, but roller lifters don't.