ok here the engine i got. 400, 9.5:1 351c pistons, lunati voodoo cam 268/276, streetmaster intake, shaved heads(ported&polished), 600 holley, headers, procomp hei dist, dynomax race bullets, 2 1/2" exhaust 3" dumps, 4 spd toploader an spooled 8.8 with 3.55's. it did have just a 268 comp high energy cam anyways the 600 holley is dieing it needs rebuilt. i worked some OT an i'm gonna go carb shoppin give my buddy the 600 for his stock 350. i called BG, proform, and quickfuel. an talked to jegs an summit. summit talked highly of aed an recommended the 750 ho. BG said 750 speed demon or 750 mighty demon with annular boosters, proform said their 750 street series. quickfuel said if i want vac secondaries their hr 680 or their hr 750. i really like the mighty demon. i dont really know bout aed so i wrote it off. i read alot of bad stuff on proform. quickfuel has good reviews but isnt proform put together at the same place an everyone say BG tech sucks but they were first to contact me an kept in touch quickfuel was last not to say they might have been the busiest. but all in all here are the choices. 750 mighty demon annular boosters, 750 quickfuel hr series, 750 proform street series, or aed 750 ho. thanks any insight. i am going for demon but before i order i want one last look at it all. also i want to get this carb because i am fixing to start build a 9:1 comp mild 460 for my f100 so maybe in next year or so i can drop it inthanks leland

 

Assuming 5500 rpm max, at 85% VE I calc the CFM out to be 540- so 600 is plenty. If you have an auto, use vacume secondaries, a stick, go with mechanical secondaries. With regards to a street vehicle, I would avoid fancy, use either a holley or edelbrock.

 

Agreed, don't get all wound up thinking you need a big carb with a 400 cube engine. My wife's 427 Corvette uses a Holley 650cfm spreadbore and gets 17 mpg easy, and my brother has a Holley vac secondary 600 on his 406 cube Chevy that cranks out over 400 rwhp. Smaller carbs mean better street manner, better mpg and more low end grunt.

 

thanks for the info. i woulda hated gettin saddled up with too much carb. i may just rebuild this one an use the money for a better intake. i just got a streetmaster i was told an action + is good bang for buck for the 351m/400 and maybe put some scorpion roller rockers (1024) if i go to a pedestal mount roller rocker will i need guideplates or hardened push rods? or can i just bolt them on shim them if i need an go?

 

Something like a 670 Street Avenger sounds like what you might need.

You do not need guide plates with pedestal mounted rockers.

You might look into the Crane adjustable set-up for pedestal mount rockers. I used it on a 351C years ago with some Erson roller rockers.

 

ill defiantely look into them. i also seen scorpion pedestal mount roller rockers pt # 1024. on the carbs just by chance have you seen anybody with reviwes of the summit 750's. they have the elec. chok/ vac secondaries and the manual choke/mech secondaries. they are a bit cheaper wonder how they fair for the price?

 

well i have come to this conculsion i am either gonna run a holley 4777c or a quickfuel hr-680. one being a 650 mech secondary an manual choke and the other being an electric choke vaccum secondary. i have vaccum secondaries right now. most of the carb manufacturers said 750 but like everyone said thats big an i did the 2 methods of checkin 408 x 2 - 15% and then 408 x 5500 / 3456. 650ish is bout the middle of street and race cfm. vaccum or mechanical? i never ran mechanical but demon,proform, an half a dozen others all said that was best. i got a 4spd but i'm not that light 77 swb f100. but i do know anything would be better then that 600 holley id even go eddy to get me by an i dont care for them. maybe even q-jet with an adaptor ;p

 

If you have an automatic, use vacume secondaries, a stick, go with mechanical secondaries

 

well i got a holley 650dp , weiand action + intake, and a 1" swirl torque space so i can clear my dist cap. hope it all works out good.

 

Should work fine.