Classic & Vintage - rebuilding vintage fuji roubaix from frame/fork up, help?

hi i was wondering what groupset would be the best? ive been reading and narrowed it down to the shimano 105's or 600's. not really looking into "brifters" so will be looking for a set of downtube shifters as well. ebay has several and has made it hard for me to decide..

note, i only have fork and frame. 1989 Fuji Roubaix.

EDIT:
i am trying to make this into a 7 speed? 2 chain? 2 CHAINNZZZZZZ..sorry couldnt help it. total noob at this..its all the "42x52" 2 chain, 7 speed type of terms that really confuse me. just dont want to go out buying parts that might not even be compatible in the end. thank you.

I would go full Shimano 600 6400 series. Great function and still affordable. Dura Ace is nice but most wont notice anything except the higher price.

i'm in love with early '80s shimano 600. it's super smooth on my latest build. but don't buy it -- just makes prices higher for me.

why 7 speed? what's the frame's dropout spacing? if it's 120mm, i'd keep it a 5-speed. if it's 126mm, i'd just go 6, something like a 14-28t. more (7-speed) is not always better.

post a pic if you're able. good luck.

Go 8 speed if you can, 7s gonna be cheaper finding down tube shifters. Just buy a basic Sram 8 speed chain.

Let the deal decide. I just rebuilt a Roubaix, that originally came with 105, with all RSX (a lower group). Why? Because the 105 bits all went to other projects, and I picked up a donor bike (damaged frame), that came with full RSX. The Roubaix started as a donor bike, supplying parts I used to rebuild a Cannondale. Its one continual cycle, I hang onto good donor bike framesets, to be rebuilt later, and donate off the ones in poorer condition.

I like the donor bike route, I swap everything. That way, I know all the parts play well together, and its a lot cheaper than trying to buy individual parts, whether used or new. The price of my donor bike was less than what a decent set of wheels would have cost me. And from that donor bike, I took the brakes, stem, handlebars, brake levers, wheels, cassette, crankset, shift levers, saddle, tires, tubes, and pedals. The seat post (wrong size) went into my parts bin.

The choice is yours, but building up a frame, if you buy parts individually, will almost always cost more than what you would pay for a complete used bike.

For 7 speed, I always use KMC Z50 chain, durable, and affordable (cheap). Last time I picked up Z50 chain, it cost me $5.62 each (price match, on Jensen). Anymore, most of my internet parts come from Jensen. They will match pretty much any of the other suppliers, and they offer free shipping on orders $50 or more. I see Niagara has added free shipping on $100 or more. Thats an improvement (shipping tends to cost about 10%).

The best? Well Dura Ace may well be the best, but could set you back $400 or more, depending on which era.

Regardless of which group you go with, choose the dual pivot brakes over the earlier single pivot versions.

so i went up to Santa Barbara and picked up the Fuji Roubaix frame/fork. Surprisingly, the frame was in better condition than i imagined it to be. No dents as stated, just dirty/scratches.

Unfortunately..i have a feeling that the fork might not be the original fork, i was looking for the "FUJI" sticker that is pictured on classicfuji.com and it wasnt there. is there ANYWAY to determine what the fork is? deal went smooth, just bummed out about the fork.

anyone selling a 1989 fuji roubaix fork i will buy it right now..

will post pictures, hopefully you guys can help me out determining whether its original or not.

thanks.