so the thermoquad on the 360 in my truck has started acting up - inconsistent idle , had to unhook choke because of flooding etc . hey , its 30+ years old . I put an edelbrock performer intake on it when I regasketed the motor and put headers on it and ran the t-quad that way . overall ran pretty good but I knew eventually it was gonna be time for a carb change . had an idea a while back I wanted to try and last fall at 'da valley picked up a decent , complete looking holley 650 vac secondary spread bore #80555 . but they are ugly . got a quick fuel kit for it and put on a spare set of #3310 style bowls basically ( mod's needed - have to redo the pump shot passageway and bowl gasket and modify rear bowl where the right rear carb bolt is . the pic points to spot where the original hole in metering block was ) . added a quick fuel adjustable vac unit and got a new holley electric choke assy also . think I've got about $175 in'er . popped on a 1" spacer and used carb mount studs not bolts - tight fit - went on pretty good overall with front bowl removed . easy back on . couple pump shots , hit key , started right up . after about 10 seconds idled nice , good quick response , crisp sounding . even with no choke hook up yet . now comes the part where I have to hook up the linkage . fun . and then road test it . thought this might be an option for someone with a cruiser - bolts to stock or TA intake without adapter , looks pretty good . not a "race" carb by any means . but we'll see how it goes when I kick it in the fanny !
when I first started thinking about it I thought it was just gonna be a quick bowl change and WALA - done . nope . once I got it apart and checking it out saw the dif pump shot channel locations . but , bowls just hold fuel so ended up the carbs metering block hole was just right for a 8-32 or 10-32 tap ( I think ) ( edit - 10-17-17 : just did another set of metering block mod's on a dbl pumper version . used 6-32 tap ) . screwed in an extra little screw I had laying around , filed it down smooth and redrilled hole to match up to bowl opening . had to grind down pump casting on back bowl for stud clearance and find studs just the right length . dremel'd the manifold plenum a little to blend a couple ridges below 1" 4 hole spacer .
throttle cable and kick down hooked up , short quick test drive , raining out . back in shop . still need to power up choke and look over the cruise cable hook up situation - it swivels ? and dbl check the usual . slight fuel leak where line meets front bowl to check out . let it warm up , headed out . on slow acceleration seemed to upshift a little early . seemed to act the same under moderate acceleration . will have to check kick down adjustment . power wise really could not tell much - about the same pre adjustments . more power and better fuel economy of course is the goal . but ran pretty decent overall . couple installed pics . and also included a pic of the holley #20-7 bracket which allows easy throttle and kick down hookup on mopars . the lower carb lever on this model carb is a little dif so had to modify a little - drill one hole , enlarge one on lever a little . and used my bench grinder to bevel the head of a cap screw instead of their nut n bolt for a little more clearance on top mount . the bracket looks like it could maybe be handy for some dif applications - pretty general looking . about $10+ at summit . I got one at advanced . truck has the dual pickup ignition , not really likin' that too much . has new wires , plugs , coil etc but still I can feel a slight skip . have my eye on a NOS mopar performance change over distributor kit on ebay .
update : choke hooked up , adjusted to "center" , seems fine . opens up full after maybe 30 seconds of run time . cold weather ? probably have to adjust idle speed with choke on later . initial idle and throttle settings close - backed off throttle about 1/4 turn - good , idle screws turned down 1/2 still smooth , turned down 1/2 stumble so back to a total of 1 full turn out . fuel leak at fittings still ? after 3 disassemblies and inspections and 2 sets of inlets and fittings ended up old school - a little thread sealant on flare nut threads , rubber hose n clamps = no leak . maybe try something dif later . ended up with crisp throttle response , warm idle in park = 700 , warm idle in drive = 600 - and steady . still raining out so full road test will wait . can check secondary kick in then . hope that's functional . is so can check the upper end better . and check trans kickdown .
