I know I know...it's a banger but It has all the goodies, a vintage Cragar/Miller head Clay Smith cam 2X2 intake with two '81 Strombergs Mallory ignition 4 into 2 into one header 3.56 rear end T-5 from a jeep 7.50 x 16 tires It just hasn't run...performed to my meager banger expectations I blamed it on being in a '31 Victoria with a heavy stock interior and much more glass than any of my other A's. It is also full fendered and a friend 'surprised me' by installing a 3.54 gear set from the stock 3.78 when we shortened the driveline for the T-5 install....so I was resigned to it being what it was Talking to a buddy that is into A/B 4bangers way more serious than I am...he shared that his new build was a dog on the wheel dyno and didn't meet his envisioned expectations until.... he uncapped the exhaust and it gave him a 30hp increase along with the top RPM increase ....a whopping HUGE number when you are in the 100hp camp to begin with. It got me thinking when I put this car together I had an old beat stock A muffler that was punched out so I welded a header flange to the inlet and put a stock tailpipe over the drive axle....done the exhaust tubing is 1 5/8" I have an exhaust set up that I got from @denis4x4 that is 2 1/2" header flange to 3" thru a glass pack and 3" out dumping at the back of the running board I've had it on my Cabriolet and it made me decide to build a set up just for it as the denis exhaust makes it sound like a flathead farm tractor I just installed the denis exhaust on the Vicky..... I have a "calibration hill" that is a three mile pull from 6300' elevation to 7100 with a 4% to a 4.5% grade at the top of the hill with the original exhaust set up....42 mph at the top in 3rd just ran up Calibration Hill and 59 mph in 4th with some traffic challenges Maybe my dog can hunt....
Any idea what your cruising rpm is on the highway in 5th gear? Maybe a little more rear axle would help?
Phil....good point 65mph is about 1830 rpm in 5th On the flat with a slight headwind it gradually drops off to around 1600 and I upshift out of 5th I had never intended to put a 3.54 gear and intended to leave the 3.78 and always have talked about changing it back to the 3.78. But the exhaust swap has changed it dramatically....it has dyno'd at 86 hp on a wheel dyno...with the old exhaust. I think it is due a trip back to the dyno and some more driving My Cabriolet with a FH pulls fine in 5th with about the same final drive ratio. It turns 1900 at 65mph but it is lighter
The Jalopy Journal
