MrsSnowtrooper

Hi, I am fairly new to the technical side of cars. And a complete baby when it comes to classics. However, my hubby and I have bought a 1966 Belvedere with a 318 polysphere A engine in it. As far as I can tell, there doesn't seem to be any after market parts on it. Seems pretty much stock and has what the fender tag and engine stamp said should be there. We have been desperately trying to track down the issue as to why when the engine is put into gear it stalls out. I am looking for ideas. We have already had the tranny looked at by a specialist and 3 classic car mechanics have looked at it and 2 out of the three were stumped and the 3rd said it could be a problem with the idle mixture isn't right. We worked on adjusting the mixture by ear (just don't have the funds for a tachometer at the moment). Once that was done we tried to put the car in gear. Though it didn't die after a couple of tries, the engine yanks like no ones business. Hubby is out getting a timing gun, as someone mentioned to him it could be a timing problem. We are going to get the timing back to factory specs (from research 10 degrees BTDC). Then adjust the idle mixture and the other screws on the carb (sorry don't know exactly what they are called) by ear. Recheck the timing to make sure it is still lined up, adjust it if needed, then try again to shift into gear.

I am just wondering if there is anything else outside of this that we can look for. We have checked, double checked, triple checked, and checked again for any leaks. I don't think the carb has been cleaned out recently (or ever). Tranny is fine and was told it isn't a tranny issue. Is there anyone with a new idea?

Thanks

moe7404

the best way to adjust idle mixture. set the idle speed screw a little lower than the setting for use. then adjust each mixture screw for best idle. all you really need is a good ear. then set idle rpm for the needed speed. and check the mixture screw again. the mixture screws should be 1 1/2 turns out, plus minus 1/2 turns. running RPM should be 500 to 750 RPM. out side of that range something is wrong.

DodgeAddict

I haven't run a Poly in years but check & see if the carb & carb base are tight

MrsSnowtrooper

Thank you for your info. After everything we did today. We found out the carb is bad. Taking it to be rebuilt. Will let you guys know how everything goes after we get it back.

MrsSnowtrooper

Now that we are looking into getting the carb rebuilt, we are actually looking into switching from 2 barrel to 4 barrel. Looking at all the parts from Edelbrock. Looks like it is going to run around $750 to get all the parts. Hubby has switched out an intake manifold and carb before so we think we can do it ourselves. Seems pretty straight forward from looking at the engine and diagrams. What is everyone else's thoughts on this?

LUVMYGTX

Hi you may also think about a Holly I find them easier to set up. Ask tech. at summit they are great!!

Best of luck sometimes these things are tricky.

TVLynn

What ever you do be careful The 318LA and the Poly318 are different engines The Edelbrock intake is probably for a LA motor IT will not fit the poly. I don't think anyone sells it anymore so you need to look on the used market or Ebay.
You could get a Holley 2bbl along with a adapter if needed. better to stick with stock if the carb is repairable.
also does it have pwr brakes ? pwr booster could be leaking also a bad PVC valve

MrsSnowtrooper

It doesn't currently have power brakes. Something else we will probably be looking into adding. My hubby was telling me the same thing, so I was going to call Edelbrock tomorrow and ask. This is going to sound ridiculous but I assume Holley is a manufacturer. We don't need a new intake manifold unless we go 4bbl. Thank you for all the help.

66belvkm

Check with auto zone for a rebuilt carb.I had good luck on my 66 sport fury 318 poly. It was a 2brl. carb. All you need is the # on side of carb. and they can order one for you.

moe7404

the O.E.M. 2 bbl carb for the 318 poly has two screws in the back that go from the top casting into the bottom casting, do NOT over tighten them, just snug is all you need. if to tight it will warp the top casting and be hard to get it to idle good.

383mopar

good luck on your build, my brother and i just got our hands on a 66 satellite.