This is a good read for your build.
It's retrofit, dated and the prices have changed.
https://www.streetmusclemag.com/tec...-a-hydraulic-roller-cam-in-a-big-block-chevy/
The $910 kit they used, with .510/.510 is on sale for $1325.66. It is FLAT TAPPET...
https://www.summitracing.com/parts/cca-k11-423-8
Here's the cam I have available, (94150 miles, in very good shape... you can have for 1/2 price of the new one, plus shipping.):
https://www.summitracing.com/parts/mel-mc1316
Your machinist can polish this camshaft surface or you can have it re-ground to his custom specs.
A cam blank is a cam blank. Or is it?
My advice, is buy good used OEM, WITH THE ADDITIONAL HARDENING, USUALLY NOT AVAILABLE FROM AFTERMARKET CAM MANUFACTURERS... and have YOUR man work his craft and make it better... Melling makes a lot of OEM parts, so the billet cams, (even used), are far better than aftermarket off the shelf non-billet cams. (As a general rule...).
You'll know your machinist customized it and you can always send it back for a more aggressive profile, if your not satisfied.
These are the stock lifters you might want, if you go with the spider:
https://www.summitracing.com/parts/mel-jb-7003
These are link bars, for a retrofit engine without the bosses for the spider and OEM lifter locks:
The Melling Horizontal Link Bar Roller Lifters are OEM quality and they are not cheap:
https://www.summitracing.com/parts/mel-bb969rf16/make/chevrolet
Lot's of issues with sub standard quality on cheaper lifters...
Most domestic lifters are made by the same company in Detroit, but with different grinds and proprietary oiling orifices...
Stay away from anything in a white box... The Melling rollers, in the lifters, have the same billet hardened steel as the OEM cams.
Melling is good enough to 500 HP on a street BB engine,
in my opinion. Any manufacturer can accidentally have a lemon lifter, at any price, in the box. Check with your machinist to confirm, if there's any doubt.
If you go more than 500HP, the link bars' performance probably outweighs the cost effectiveness of the OEM spider.
The spider is not made to handle valve float. If you screw up pushing the envelope, the spider might let you down.
There are very strong performing engines using spider, just no boost, or power addres or wild converts or rediculous high rpms.
This link offers an entry level assembly for dome pistons with dual valve reliefs:
https://www.summitracing.com/parts/esp-18001l030/make/chevrolet
You can spend $1000 more than that kit, for better rods and a forged crank...
Choose your machinist wisely. Avoid the package deals and "money saving" kits...
The rotating assembly link I posted, might be cheaper if you buy all the parts individually, so do the math.
Even if you go with a mild/stock cam and build the top end for longevity, a modern metals bottom end and better than stock rods are a good investment, if you can afford it. Forged Cranks are not necessary for street use, as years of testing results has proven.
The metallurgy has improved for Cast Cranks, just buy from quality manufacturers.
The up front machine work and a proper built bottom end, is where my budget for my Big Block hit the wall.
The "affordable" Eagle rotating assembly from the link above, plus the machine work...
...is getting closer to $6500... (up over a grand from 2 years ago).
Shipping to where I live ruins everything, B/C LTL freight charges.
The reason I'm not building my BB... No machinist for well over a hundred miles...
I refuse to sink 3-4 thousand on a top end using stock bottom internals.
The L29 rods are not rated for exceeding much more than stock HP.
The crankshaft is not rated for much more than stock HP...
Your pics do not allow us to see your valley and if it has castings for OEM 454 roller lifters and the spider.
It looks like you have the casting for the cam thrust plate?
The billet cam I have is stepped for the thrust plate...
The timing cover I have available, has 6 bolts and is cast aluminum. It has casting blanks, where 2 additional bolt holes could be drilled, for use with an eight bolt Mark XX.
It has the crank sensor and crankshaft reluctor for timing trigger.
I have the OEM distributor, coil... everything you need for a trigger fired 7.4L, available.
Check your block casting numbers and verify what your cam bearing sizes are.
I have the Complete set of GM Repair manuals for the Mark VI L29 7.4L, here on my desk, with all the data for my engine and every engine available for the 1999 model year.
The cam bearing sizes and tolerances are listed in detail.
If they match your engine, I might have some good roller parts for you.
If you can use a stock OEM L29 cam, for fuel economy and longer engine life, I have almost everything, except the lifters, for a stock spider, with stock locks for you, ready to ship out.
If your block has room for a good quality OEM L29 single row timing chain and you can fit the crank reluctor wheel on your engine, you should consider installing one. The OEM L29 timing set is not cheap. Single row is good for 120K miles or more.
It's a wear part and should be changed during the life of your engine.
Double row does not fit with the reluctor, so don't go crazy over double roller, (...unless you have a machinist in the family to custom grind your block for double roller spacing).
Shurkey wrote an excellent write up using older Mark IV engine blocks and L29 heads, what it takes and what parts work.
This thread sums up hundreds of different threads, where good guys barely articulate the details; and leave you guessing.
He really covers it well.
https://www.chevelles.com/threads/l-29-heads-on-mk-iv-454-block.34285/
My L29 heads might be spoken for. If not, I'll let you know.
I would be careful if selecting Non-GM Caste Iron BB Heads.
There is a reason the GM heads are more money.
The velocity shapes in aftermarket intake ports are not the same as GM.
The flash and poor castings, thin valve stem walls, on cheapo heads can be brutal and the cost to rework them can erase the money you thought you saved.
You are paying your machinist a lot of money per hour to de bur, re-weld and correct poorly shaped or hacked machined surfaces.
If your machinist tries to sell you cheapo heads, hire a different one.
https://www.summitracing.com/parts/nal-10141280
Basically, you decide what your budget is, if you want to go OEM roller or link bars on an affordable stock roller cam.
You can usually save a few bucks not buying "the kit"... so price out what is in the kit separately.
This is the result of three years of research, hoping the engine I have could be rebuilt without full machine service.
I hope the information here, allows you to make an informed build strategy and saves you time and money.
If you go the rout of regrinding a billet OEM cam, it might take a few weeks to have one reworked.
It has become very popular and teams such as Avon Camshafts are swamped with regrinds.
The aftermarket crap-shoot has caused a lot of builders to demand OEM regrinds...
Send your machinist a Christmas turkey. Get him a Snap-On or Amana Machine Tool Supply Gift Card...
Then square that new block.