73-87 SWB PU BBC headers

Two questions-
1. My BBC is built to produce power from 2000 to a peak at 5500 Rpm. (block would go more w its steel crank. Studs and "Bone" rods w ARP bolts)
Would the bigger 1 7/8 Primary tube headers be best or the 1 3/4 Primary tube headers? This will be a limited driving show n go truck. Rarely if ever seeing track time at all and no daily or hauling/towing use. Desktop Dyno shows a significant increase using the Big tube style. BUT, I do not trust that program much. (Fun to play with the mods and numbers,but not very accurate in my opinion.)

2. I've also asked this one on 67-73ChevyTrucks.Com. For BBC Chevy truck builders/owners. I am on a budget so I am wondering if other style/model BBC headers fit a BBC 73-87 PU (2WD). The big tube Hookers are way spendy for my budget and a little info would make swap meet hunting a bit easier.


Some stats for info-
stock 049 heads a LS6 springs, ret +keepers (big valves planned)
8.9 Comp

cam -Idle to 6K-
Adv. Dur 292-I/302-E ,
Adv. lift 503-I/528 -E,
Lobe spread 107 deg.

High rise single plane(Wieand)
780 Holley Vac sec. modified w a ProForm main body W supposed 900 CFM flow, Holley quick change Vac. sec. spring housing and later PV blow thru protected base plate, Carb might seem kind of big at first glance, but the big CFM won't be used unless in WOT w those Vac sec's.
Full 2.5 exaust out the back (planned not bought as yet, might go 3" but do not an ear drum breaker)

(Pic shows a Edelbrock carb and Nova headers I just had laying around)

i would say you may not see much from a 1.3/4 to1.7/8 tube header this would have alot to do with rpm your going to be at most of the time and if both headers are the same primary size as .as for your stock rods . many guys and i have built many bbc with stock rods .i have built bbc with stock 3/8 rods with sps or arp bolts rod bolts with stock cast iron cranks two bolt blocks that have seen over 6500 .i think your carb is a bit big along with intake if your truck if is heavy .i like the stealth dual plane weiand