I currently have a 355 4 bolt block, RPM Air Gap, Holley 750 cfm dual feed, mild cam (sorry no specs),GM cast iron ported and polished heads and blackjack 1 5/8" headers. I didn't build the engine so I am lacking specifics. I plan on upgrading to a World 427 short block assembly sometime down the road. In the meantime, I would like to wake up my 355 with some bolt ons I could swap over to the short block. I am in the process of freeing up some horsepower by upgrading to an electric water pump and fuel pump. I'd like to now focus on the top end by adding AFR 210 Eliminator heads and convert to a hydro roller cam and roller rockers. What cam, rocker arm ratio, heads would work with my existing combo and eventually work with the 427 short block? Changing the cam with the 427 swap wouldn't be an issue but I wonder about the 210 heads on a 355. Very open to suggestions here since a stock vette will give me a run for the money...I am looking to change this.

That's a tough one. You need some BIG stuff to feed a 427 SBC, the biggest you can buy. Even the 210cc heads are way too small for a 427, you need 220-230's.
And a 427 will eat up a LOT of camshaft.

Mark's 427 idles almost like a stocker, and will cruise down the highway at 2000 rpm in overdrive... with brodix 227cc track 1's and a near 260@050, well over .6" lift solid roller!

That's a tough one. You need some BIG stuff to feed a 427 SBC, the biggest you can buy. Even the 210cc heads are way too small for a 427, you need 220-230's.
And a 427 will eat up a LOT of camshaft.

Mark's 427 idles almost like a stocker, and will cruise down the highway at 2000 rpm in overdrive... with brodix 227cc track 1's and a near 260@050, well over .6" lift solid roller!
In concurrence with JimM.....
I had track 10 Brodix heads with 230 runners, .630 Erson Solid roller in a 421.
My suggestion is some AFR 195's, a XR282 or so, a dual plane if auto tranny-Victor Jr if Manual tranny, then get 427 and then sell 355 complete carb to pan. I am REALLY into BIG SBC's. I have several on paper that I plan on doing in the near future....upwards of 650hp on pump gas. I had some help on parts choosing.... Bill Mitchell blocks, AFR heads..blah, blah, blah....the smallest anything you put on your 427 is STILL too big for the 355 by a long shot. 427's can move some serious air.
jm.02 as always....Good luck. Gonna build the 427 your self? May I suggest some reading from Reher-Morrison? I learned enuff to know a nice (big) SBC is better than a BBC....in my humble opinion. Sure makes them mad to outrun the BBC guys when you run a 421. :D

i agree afr 195s with like a comp XR282HR or 288. sounds good and make good power to round 6k. My 350 put 447hp and 422 trq to the flywheel with Edelbrock RPM 200 heads, comp XR288HR, 10:1 comp, flat top pistons, and an edelbrock air gap intake with a holley 750dp. Roller cam all the way man:beers:

I knew you guys would quickly put an end to my debate. It looks like AFR 195 eliminators and a XR 288HR is in my future for the 355 block. I should be OK with my 2800 stall converter. I will continue to save and dream of my 427 SBC build.

What horsepower / torque numbers could I expect with my set up with the new heads, cam and rockers?

Canfeild 197cc heads work well as does the Crane HR #119841
.539/.558" lift 234*/242* dur.
Runs very low 11's