Dave145
Well-Known Member
Howdy everyone! Been a minute since I posted on here. I have a '64 Polara with the poly 318 under the hood. TF pushbutton trans, and 3.23 gears out back. Not a racecar by any means, just a cool old cruiser.
First let me tell you about my motor and setup. The motor was "refreshed" in 2019. Rings, honed cylinders, bearings, timing chain, gaskets and paint. Lapped the valves but otherwise did no heavy machine work to either the block or the heads. The car always ran decent for what it was in stock form as a 2 bbl with points. That being said, I got a little hungry for more power and I seem to have fell off the wagon somewhere. First I added electronic ignition using the mopar performance kit. Then I recurved the distributor and played with the timing (Current setup as of today is 12* initial, 34* all in by 3200rpm, 50-52* vacuum advance hooked up). I also played with the valves, running the FSM recommended .013 and .021 at first, then .015 and .023, all the way up to .017 and .025. For grins I tried running them down at .010 and .020 at the suggestion from a friend, and I didn't notice anything special. The car ran...ok. Definitely had a bit more power but not by much. Then I added dual 2.25" exhaust from front to back with an H pipe and turbo mufflers. Didnt seem to change much. So then I decided to track down a factory single 4bbl manifold off I believe a '61 Dodge and added a Summit Racing 500cfm vacuum secondary carb and a spacer on top of it.
This is where I fell off the wagon.
The car is now a bigger dog than it ever was. For grins I shot it down a 1/4 mile stretch of road by me, in stock form, modified out of the box form, and "tuned form". As a 2bbl, I could chirp the tires from a standing stop and run a 16.XX second 1/4 mile. In modified out of the box form, I ran 18.XX seconds. Finally in "tuned form" (re-jetted, played with squirters and secondary opening, etc.) I ran...wait for it...19.xx seconds. All of these tests were performed a year ago all pretty much within a week of each other on the same road with pretty similar weather conditions. Did I forget to mention my fuel economy with regular driving decreased drastically too? Went from around 17 with my Stromberg WW 2bbl to roughly 10.
You could say I'm pretty stumped. I'm not exactly new to tuning old engines and carburetors, but this one is a head scratcher for me. Especially since everywhere I read online says that doing nothing other than adding a 4bbl manifold and carb supposedly really wakes up the poly. I'm pretty limited on funds at the moment so a new cam or even an engine swap is out of the question for me so I'm just trying to work with what I have.
I pulled the intake and carb back off figuring maybe an intake gasket was leaking, but it doesn't appear to be the case. Prior to removal, the motor made 18-19" of vacuum at both the carb and intake fittings and didn't burn any oil or coolant. I pulled my plugs and they all look good except for #2 which has the slightest amount of oil on it. Otherwise they were all even colored all the way around.
Any ideas?
First let me tell you about my motor and setup. The motor was "refreshed" in 2019. Rings, honed cylinders, bearings, timing chain, gaskets and paint. Lapped the valves but otherwise did no heavy machine work to either the block or the heads. The car always ran decent for what it was in stock form as a 2 bbl with points. That being said, I got a little hungry for more power and I seem to have fell off the wagon somewhere. First I added electronic ignition using the mopar performance kit. Then I recurved the distributor and played with the timing (Current setup as of today is 12* initial, 34* all in by 3200rpm, 50-52* vacuum advance hooked up). I also played with the valves, running the FSM recommended .013 and .021 at first, then .015 and .023, all the way up to .017 and .025. For grins I tried running them down at .010 and .020 at the suggestion from a friend, and I didn't notice anything special. The car ran...ok. Definitely had a bit more power but not by much. Then I added dual 2.25" exhaust from front to back with an H pipe and turbo mufflers. Didnt seem to change much. So then I decided to track down a factory single 4bbl manifold off I believe a '61 Dodge and added a Summit Racing 500cfm vacuum secondary carb and a spacer on top of it.
This is where I fell off the wagon.
The car is now a bigger dog than it ever was. For grins I shot it down a 1/4 mile stretch of road by me, in stock form, modified out of the box form, and "tuned form". As a 2bbl, I could chirp the tires from a standing stop and run a 16.XX second 1/4 mile. In modified out of the box form, I ran 18.XX seconds. Finally in "tuned form" (re-jetted, played with squirters and secondary opening, etc.) I ran...wait for it...19.xx seconds. All of these tests were performed a year ago all pretty much within a week of each other on the same road with pretty similar weather conditions. Did I forget to mention my fuel economy with regular driving decreased drastically too? Went from around 17 with my Stromberg WW 2bbl to roughly 10.
You could say I'm pretty stumped. I'm not exactly new to tuning old engines and carburetors, but this one is a head scratcher for me. Especially since everywhere I read online says that doing nothing other than adding a 4bbl manifold and carb supposedly really wakes up the poly. I'm pretty limited on funds at the moment so a new cam or even an engine swap is out of the question for me so I'm just trying to work with what I have.
I pulled the intake and carb back off figuring maybe an intake gasket was leaking, but it doesn't appear to be the case. Prior to removal, the motor made 18-19" of vacuum at both the carb and intake fittings and didn't burn any oil or coolant. I pulled my plugs and they all look good except for #2 which has the slightest amount of oil on it. Otherwise they were all even colored all the way around.
Any ideas?
