It sounds like you're getting some great advice on this thread, and I can tell you that it's a "deja-vu" moment ... almost identical to my 454 build dreams and real-life experience.
Yup, I wanted the 8-71 blower sticking outta my hood too, (still sorta do.
) as an "upgrade path".
I started out with a good core, then had it built with .030 Forged Flat-tops, 781 (118+ cc) heads, Air Gap intake, Holley #3310 750CFM VS carb, Hedman truck headers, TH400, B&M Nitrous Holeshot 2400 stall convertor, 3.73:1 truck diff.
Cam #1, original to the fresh rebuild, had similar specs to a "blower cam" with a 224° duration on 114° centerline (IIRC) and it was LAZY picking up RPM.
We had break-in issues, and it wiped a lobe ... which probably contributed to the "lazy" as well. I thought it idled much too smoothly anyway.
So, faced with replacing the cam, I went overboard and installed cam#2, an XE284H, looking for a rougher idle ... which I got. It turned out to be pretty much "un-tunable" in fact. That's when I learned about DCR.
So OK, the intake was puking oil out the china wall, so I decided (with advice received here) to peel it off, replace the gaskets, and just use silicone on the rear china wall. When the intake came off, I found that I had other problems ... some NASTY Technicolor goo in the LH rear cooling port on the cylinder head. I suspected it was caustic soda, so I cleaned it up, re-assembled the engine, flushed the block and rad, adjusted the rockers, and fired it up.
The good news? No more oil leak.
The bad news? I must have made an error when adjusting the rockers, and wiped another cam lobe.
OK ... enough! I went out and bought ANOTHER flat-tappet cam (XE268H) as well as a set of closed-chambered (110cc) 396 heads, trying to get that compression up.
Having discussed flat-tappet cams at great length, I cannot bring myself to put it all back together again.
At this point in time, I have the short-block sitting in the frame under a blanket, A new cam and lifters in their un-opened boxes, 2 sets of heads on the bench ... and a strong desire to spend my cash on vacations rather than on this boat-anchor 454!
OK, seriously, I do plan to buy a ROLLER
cam with a similar (performance street) profile XR282HR and put it together with the higher-compression heads. The blower thing may never happen, But I'll keep those 781 heads in case it does.
Hopefully you (and maybe others) can learn from my misfortune, and not make the same mistakes.