Ted: On your carburetor test engine, those are interesting test results. For reference purposes, what cam does it have & is the compression near stock? Thanks

Paul

Hooking the choke up to the coil or anywhere in the ignition circuit is typically not recommended due to making for a voltage drop at the coil.  If running an electronic conversion in the distributor, this can cause a premature failure of the module or at the very least, just hard to start.

Lorena, Texas (South of Waco)

The stamped numbers on base of the 1.08” carb I’m using for testing is “6Z P” while the jet sizes are 47 primary & 57 secondary.  The original tag on top is gone.  This was the only 1.08” carb sitting here that was in a runable condition but idles and runs well.

Lorena, Texas (South of Waco)

The Road Demon Jr. on my ’55 with its 272 is using a pair of 61 jets on the primary side instead of the factory installed 58’s.  My particular engine combination just drives better being jetted this way.  I also modified the ported vacuum circuit to provide a stronger vacuum signal for the distributor for an increase in ignition advance during cruise situations.

Lorena, Texas (South of Waco)

The engine is +060 over and the pistons are 0.025” in the hole.  The static compression ratio is a real 9.2:1 while the camshaft is a Crower Monarch grind with the duration being 238° at 0.050” and advertised 0.450” lift.  The actual lift at the valve measures right at 0.400” with aftermarket replacement rockers that are currently being used.  I’ll eventually get around to testing the various oem rockers ratios as well as the Thomas, Dove, Rocker Arm Specialist, and Harland Sharp rockers that are sitting here.  A serious header test is still in the works also.  Those stock heads are not being very responsive to changes though so I may end up changing heads in the near future to get some more definitive results on what the different intake manifolds are really worth.  Head flow is currently the bottleneck for increasing the performance on this particular engine.

Lorena, Texas (South of Waco)

This is a great topic.

Back in '67 I had a stock displacement 312 in my '48 Tudor. The only mods it had were a B7A-C cam, a Mallory dual point conversion and Hedman T-Bird tri-y headers. T-10 transmission and 4.57 open 9" rear end.

I found a 715 CFM Holley from a Shelby GT 350 for cheap and bolted it on with 2 stock spacers.

My good friend had a '62 406 4v 4 speed Galaxy 2 dr. We took our cars to Dragway 42 one Sunday for kicks. We were able to line up together for one run.....I WON! Couldn't believe it! My et was 15.24, I don't remember the mph. We were both on street tires. Anyhow my car really ran good with that carb. Back then we did a lot of street racing and it was a thrill to beat GTOs and an occasional 442 with that old hot rod! It seems to me that Y blocks like to be over carburated a tad. It's great that Ted is doing this dyno testing.

P.S. I loaned that carb to that same friend and never got it back. I wish I had it now!

FIGHT CONFORMITY! 

sounds like you got the right carb Ted. from my research the Z in the 6Z-P would be 289 mustang. Mine is 6A-E and A is full size car with 390. suppose to have something to do with caibration of boosters and other orfices in carb.

Kenny  Onalaska, Texas

Alright, since we are on this topic, what is a 6 AF?

Jan  Urbanczyk  Major USMC Ret.

                                                                 Bowie Maryland

C6AF-F 6A-F

66 390-428 Full size/Galaxie

1.08 venturi 4V 480 CFM Auto

this came from this chart.

http://www.mustangtek.com/4100/ford4100.html

I think my carb may be hacked. its a 6A-E which shows to be 4 speed but mine has auto kickdown linkage. the jets in mine are 49 and 67. my good deal may have bit me in the butt.

Kenny  Onalaska, Texas

Happy New Year everybody!

I now have my '57 B style intake & ported the bore size to match the larger 1/2" phenolic spacer. I filled up the valley areas where the remaining lip was real thin with JB weld, & filed everything flat. Took a long time, but I think it came out OK. Received the rebuilt 525 Demon Jr yesterday & will start to put it all on.

On this intake manifold (vs. my previous '56) there is some vacuum port hole at the rear. My previous intake didn't have that provision. What is that for? Should I just plug it & run the various vacuum lines needed from the carb ports? Anybody know the right size plug for this if that is the way to go?

Brian - 56 T-Bird

Woodinville WA