My Dad has a 65 coronet with a 440 and 4-speed. he has a vibration that almost feels like a missfire. He literally replaced and checked everything dropped oil pan no metal shavings did the clutch new u joints. all electrical etc. About a week ago he found a bent pushrod. Replaced it thinking it would be the problem. It still vibrates bad. Heres the thing it can be felt in neutral when reving the engine . Comes on at like 1500 rpm I think he said. Any ideas would be appreciated. He is at wits end. I would have thought it could be a bad ecu or distributer. He replaced it all.

Are you sure that you have a matching clutch plate. That is balanced for an internal balanced 440 you have a internal balanced engine 440, and not a cast shaft/external balanced plate

You might be surprised, and I've seen it before, engine seems to idle well, no obvious misfire, but there may be a wire crossed, CONFIRM the FIRING order, rotor location #1 under the cap, check the plug wire orientation


I purchased a vehicle from an ASE certified shop where the techs toiled for weeks trying to solve the "vibration" issues on a Dodge Ram,...after buying it I spent 5 minutes and found that the wires on two cylinders were misplaced on the firing order, this after the ASE techs replaced everything under the sun and were preparing to tear apart the drivetrain before deciding to take me up on my offer to buy it...sometimes it's the simplest things we over look

Matching clutch plate? Not sure what you are thinking of, but the only thing different between and internal and external balanced 440 is the flywheel, the rest of it is the same.

do a compression test to see if there ain't a dead hole. Started out of the clear blue? any parts changes/adjustments immediately preceding the onset? internally balanced? as no weights that coulda fallen off (a stretch but wanna cover everything that comes to mind). Yes check that firing order (esp 5/7). I have a similar story but it is tragic so I will pass. I would never suggest purchasing parts blindly (shotgunning) to try to solve an issue but would you have another ECU and coil you could sub in (one at a time) to elim them. keep us posted

meant flywheel. Sorry. Mind ahead of fingers.

Car has a new pressure plate and clutch. compression test was done and was fine. pulley balancer was swapped out , different fan. All did not help. Maybe It is the flywheel. It may have not been cut before new pressure plate and disk were installed. Vibration is felt in neutral. This I think would make sense. I will have ask my Dad if he had it cut/balanced ?

if it's felt in neutral and car is not moving it's an imbalance issue ... or 5 and 7 swapped ...

You never said , what year the engine is ?

and what do you mean by "pulley balancer was swapped out" ?

The engine is a 1970 HP 440 out of a cuda that was put in around 1973 purchased for 90 dollars replacing a 426 street wedge. So the motor is a forged crank .Balancer pulley. I meant harmonic balancer or damper was replaced with another just to rule it out.

It's the correct weighted balancer I assume ? There are 3 different weighted balncers for big blocks , the one for the 383/400 is closer to the 6pk balancer than the cast crank balancer is.

Also it needs a weighted flywheel , is it the correct one ?

A 1970 440 HP engine most likely has the huge six pack connecting rods requiring the six pack harmonic balancer. Does your balancer have the offset weight built into it on the front or a neutral balancer? If you have the neutral balancer you need the six pack one.

Does it have an engine driven fan? Run it with no belts.

Was run without belts and #5 and 7 plugs are correctly routed. ?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????

Rebuild time.Time to put the 426 street wedge back in her I guess.

Go ahead. Throw money away.

Verify the flywheel balance first.

Vibration is fixed . It was the rubber transmission mount was worn. Fixed everything.

I never woulda guessed that it was that.

Yeah I know rite. My Dad went through everything and read online that the trans mount can cause alot of vibrations. It was the ticket. He is very happy and has already been out to a cruise night again.

I chased a vibration for a while in one of my cars. Did the usual. Replaced motor mounts, trans mount, U joints, balanced wheels & tires and even tried a different set of wheels & tires for a while. It turned out to be the crank damper. It was all dry rotted. When I took it off & replaced it with a new Pioneer damper all of the vibration went away. Then I noticed while sitting up on my shelf for several weeks the old damper had actually separated into two pieces while sitting so yeah, it was due to be replaced.

I had a vibration also in my engine , I replaced a lot of parts but in the end it was a bad harmonic balancer. This place rebuilds balancers.

http://www.damperdoctor.com/