Since my last update I've successfully managed to ruin another split-port head by getting greedy with the carbide cutter to the point that even welding it couldn't save it.
Which was quite unfortunate as it was just about finished. So after another $160 including shipping, I have another head to start over with........again...........
I made the previously covered fuel injector bung mod to the replacement head so I won't cover that again but I did mill the rocker arm pedestals for pushrod guideplates and 7/16" ARP studs.
On an poorly timed impulse decision I decided to buy a stainless steel rocker arm kit from ebay for around $200 all in. It was a
Pro-comp/Speedmaster retrofit 351C kit. Yes, I knew about their reputation and yes I ignored that voice inside my head. I though it might be an OK value as it didn't need pushrod guide plates or machining. So they arrived, with the packaging beat up and the studs packaging open and the studs spilling out in the box. I also thought the studs base thread (head) would be bigger than 5/16" so I could just drill and tap the bolt holes oversize. That was a mistake on my part for rushing my research because the 5/16" thread on the studs is basically the same as the 8mm thread in the head and after you re-tap the 8mm thread to 5/16" the thread is too loose to use. So then I order some Heli-coils for the heads for $30 which I then ended up sending back when I realized I would be way better off just spending an extra $25 and getting 7/16" ARP studs and machining the pedestals and buying guideplates. Why I almost trusted my engine to a tiny chinesium stud instead of a beefy ARP one just to save a buck and some time on the mill I'll never know, major brain fart on my part.
The studs had their own problems too in that they were too big to actually install a rocker arm on. Every one was 0.004"-0.006" bigger than the hole in the rocker arm. So I put each on in the lathe at cut that much off of them. This was before I learned the error of my ways and scrapped them for the ARP ones.
Out of the 16 rocker arms I found 12 that I could use due to poor assembly of the pushrod cup. It was not pushed in enough to seat it properly or bottom out. Ugh...why did I buy this junk. At least the stainless steel casting seem good enough and the bearings in it seem fine and the locking nuts on the studs are ok to use but the fun times don't end there because......
The self aligning rocker "feature" that removes the need for guideplates which is now irrelevant because I will be using guideplates does not fit properly with the stock valvespring setup. The alignment tabs sit on the retainer/keeper and the roller tip of the rocker is 0.075" away from it so it never touches the valve stem. Arrrrrgh........so now it's either machine the tabs off each rocker arm or buy longer valves and associated parts so I will be machining the tabs off the rocker arms.
I've been accumulating some parts in the interm as well such as these 304SS 4.2L F-140 headers which are of surprising good quality for a product from China. The welds and overall quality are very, very good. If needed I will cut and reweld as needed but as they are going to face forward and down for the turbo it may not be neccessary.
I also bought a turbo (GT3582 clone), wastegate and blow-off valve. All of which will be getting a full teardown and overall review here when I get the time.
After that I made some flanges for the turbo out of 1/2" steel plate.
I also picked up a set of Scat 6.125" H-beam connecting rods from Super Coupes Unlimited and some more mundane stuff from around the internet like gaskets, harmonic balancer, oil pump, freeze plugs etc.
There is an issue with the intake manifold that I need to address though. The center section bolts on to the lower via 11 fasteners which are inside the intake manifold and should one come loose it will fall into the engine and there is no way to keep an eye on them without pulling the upper manifold off.
I will not just trust it to loctite only and I don't want to weld each port to the lower manifold so I think I will machine the countersunk bolt hole to a flat bottom and use socket-head cap screws (allen bolts) drilled for safety wire and then wire them all together and add a dab of loctite for good measure. So I have some re-work to do there.