Spreadbore adapter under square bore carb

[gzig5]

I'm working on a 73 Cuda with a 71 340/727 auto in it. Trying to get it to move under its own power. Finally got a new fuel tank and feed line installed and will be ready to fire it up soon. Had to trash the dry-rotted spreadbore Holley it came with and have a square bore 650 double pumper to use. I want to use the 7/8" spreadbore adapter that was under the original carb, at least for the near term because the throttle linkage and kick-down lines up much better with it. Anything I need to watch out for? The car is still in rough shape and won't be driven hard for a while until other things are straightened out. I've been out of carburated engines for quite a while but my impression is that the riser will generally help overall with idle and overall performance? Hood clearance is not an issue in this case. I have no idea what internals are present, I'm assuming stock '71 cam and other stuff with an LD4B intake and headers. LD4B will be replaced by RPM Air Gap but I have to get it moving first.

 

[67Dart273]

That kind of port mismatch WILL hurt overall "max" power for for normal / most driving you will never know the difference

 

[RustyRatRod]

Scratch all that. lol

 

[nm9stheham]

I can't imagine it not being good enough to 'move things around'.

How does a Holley 'dry rot'? LOL

 

[gzig5]

How does a Holley 'dry rot'? LOL

Car sat for who knows how long. Tank and fuel line were full of rust. There was 1/16" of sediment in the bowls and all the gaskets were toast. It's a more obscure model and the rebuild kit was twice that of a 4150 type. Decided not to mess with it and installed a better condition 650 DP.

I can't imagine there being a major issue but thought I'd ask. Max performance is not expected with this setup, just hope it will run decently enough to make short trips while I work on the other issues. Probably going to go with a Sniper or FITech and don't want to invest too much in something that will be redone. We'll find out this afternoon, hopefully. First I need to address a completely collapsed header tube.

 

[pishta]

itll go like stink with that cam/manifold/spacer combo...until you run out of port which may never happen on the street. That spreadbore is a nice carb if you could get it running. Post it up, someone may want it.

 

[gzig5]

Got it fired up and some initial adjustment on the carb such that at hot idle I've got 18-19 inches of vacuum at ~850 rpm. Throttle response seems pretty crisp, but car is still up on stands so that may not mean anything.
Went to set the initial timing with the light connected to #1 and the mark on the balancer doesn't show up. What the heck? Verified there is a mark on the balancer and then check the distributor wiring. Looks like the previous owner has installed the distributor 180 degrees out. #1 cylinder should be wired to the distributor at the 12 o'clock position, with that being the point closest to the front of the car. It is wired to the 6 o'clock position and #6 is wired to the 12 o'clock. The rest of the wires are in proper firing order, but wrong positions. So, it looks like I need to bump it over until #1 is at or approaching TDC on compression stroke, remove the distributor, rotate the shaft 180 degrees so that the rotor points to the front of the car, drop the distributor back in, re-wire the cap with the proper orientation/sequence, and it should allow me to set the timing from there? The distributor drive can only be in phase or 180 degrees out, correct?

I'm surprised the thing will run at all considering the #7 header tube took a hit and collapsed almost completely for about five inches...

 

[nm9stheham]

It sounds like the distributor is wired 180 degrees out; that is not a problem at all. Remember, the crank rotates twice while the distributor rotates once but the timing mark should still show up around 0, so you can literally time it off of #1 or #6. If it was not near the right point, then the thing would not run so well. Now if you want to get the wires in the right spots for peace of mind, then do as you described with the rotor and wires.

What you actually need to do now is to use some precise method to locate the #1 piston at TDC, like using a piston stop. Then see if the timing mark on the damper is at the 0 mark on the timing cover. Damper ring may have slipped...or you might have a pre-70 damper where the timing mark is on the other side. BTW, are your timing cover's timing marks on the left (driver's) side of the engine? Just asking in case someone put in some early parts (damper, cover, etc.)

 

[gzig5]

The timing marks on the cover are on the driver's side. This thing is a bit of a cluster*, so for piece of mind I think I'm going to verify the damper lines up with #1 TDC and correct the distributor. I've got a 2" travel dial indicator that I think should reach in there plug hole. I tried connecting the light to #6 wire thinking I would see the timing mark, but it didn't show up. There isn't much room to see more than 10 degrees advanced before the mark would be under the timing cover so I suspect there is a bunch of initial timing on it.

* For example... I drained 8 quarts of oil out of it yesterday from the stock oil pan...driver's lower rear shock mount broken and replaces with a 3/8" bolt and a couple washers... tranny lines to the radiator are in about six pieces with rubber in between sections and sandwiched between the headers and the oil pan. Long to be a long road to redemption....

 

[nm9stheham]

Oh, and if you had the vacuum advance hooked up and on the wrong port (manifold vacuum rather than the ported vacuum port), then the ignition timing would be reeeeally advanced. With all those other things so mucked up, that would bear checking.

BTW, you do have a '70 & later timing cover.

 

[67Dart273]

What you actually need to do now is to use some precise method to locate the #1 piston at TDC, like using a piston stop.

Yup..........

 

[gzig5]

Thanks for the info!
The distributor vacuum was disconnected while I was checking. It is routed to what I believe is the proper port on the upper primary side of the carb.

67Dart273
That's pretty clever. Is that hard stop or spring loaded? I've got a machine shop in the house so cobbling something like that up should be pretty straight forward.

 

[pishta]

stick a drumstick in there and lodge it against the cylinder wall and run up the piston with a wrench on the balancer bolt. just When you feel it touch, mark the balancer at TDC, now reverse the wrench rotation and run the piston back down and up again until until it touches again. Mark it again at TDC. Now bisect the 2 marks , make a big mark and thats a pretty close TDC, dead on if you marked it when it just touched. The screw in piston stop will stop the piston so there is no wiggle room. Your TDC mark is either at 10:00 or 2:00 depending on what year the balancer is but this method will allow you to mark either balancer to either year. As for the wiring of the cap, it dont matter where the towers end up, it only matters where the wires end up. Use your thumb over the #1 plug hole to determine what cycle your on, pressure is the TDC cycle. 180 out isnt going to give you 18" of vacuum.