I feel like an idiot...

Well, I've been chasing a vibration on my 74 Dart Sport with a 318/904 for a while now. Changed rims and tires, tailshaft bushing, transmission mount, u-joints, pinion angle, etc. No improvement. Wanted to rule out the driveshaft being bent/out of balance, so ordered a brand new one. No improvement.

Had a look at the harmonic balancer, thinking a previous owner might have put a 360 balancer on there. It didn't have any weights on it but looked to be wobbling, so I ordered a new one from Summit.

My starter was making a noise like the bendix was sticking, so I crawled under to have a look. While under there I decided to check the flex plate to torque converter bolts, and I noticed the torque converter had weights on it. Maybe that was the vibration, the wrong torque converter.

While I was down there I decided to look at the block and get the casting number, and what do you know, it's a 360. :banghead: The casting number is 4006830-360-6. So the torque converter is right, but looks like the balancer has lost a weight and may be worn out.

Called customer support with Summit and explained to the guy I had ordered the wrong harmonic balancer, and he said the one I ordered for the 318 would work on the 360. Well I may not know how to tell a 360 from a 318 by looking at it but I knew the one I ordered wouldn't work. Even after telling him their website had one balancer listed for 273/318/340 and a different one listed for a 360 he still said it should work. We ended our conversation with him telling me if it didn't work just return it. I then called back and spoke with someone else and got the 360 balancer on its way.

So all this time I thought I had a 318 and its really a 360, I've been buying parts at the parts store for a 318. Luckily everything I've gotten works on both. I was just going by what my brother in law and his dad told me when I purchased the car from him, and they are life long mopar guys so I figured if they said it was a 318 then it had to be so. On the bright side I have a set of headers that I was waiting to put in when I could get a 360 built for it, looks like I can go ahead and put them on....

Well you know now and that is all that matters.

Russell, This is very cool - and certainly nothing to feel like an idiot over!!! Let us know the outcome after the new hb is installed.:cheers:
C

Hey, ya got lucky with all the stuff(except HB) fitting/working...Maybe your Dart is a factory 360 car?? Now ya now, lots more potential for horsepower!!

It's better to find that you had a 360 when you thought it was a 318, than finding you have a 318 when you thought you had a 360!:blob:

I would love to find the casting numbers four and two and six on my 340

If you start with miss information at the beginning,it can only multiply and get worse,case in point,trust know one,check for your self and re-check,mrmopartech

I know I wouldn't be able to tell the difference by looking at them. :dontknow:

Maybe the balancer they sent you has the weights you add for diffrent motors, doesnt matter since there sending you a diff one just felt like typing.

Check the front of the block under drivers side head for the numbers or look on drivers side of block for casting number. That would provide a bit of support to whatever size engine may be in the car.

i had the same exact thing happen with my ol 73 D100. it was originally a 318 truck with a 4 speed. someone dumped a 360 in and used the teener flywheel and 78 vintage 318 balancer. It was obvious this truck was hashed together long before it hit my hands. good times were had after i figured out my hellacious vibration at 60 mph.

Did you ever notice your 318 seemed a little stout?

haha i wish i had that kind of idiot moment HEY MY CAR HAS A 426 HEMI and i didnt even know it.

gratz dude. that's a good mistake lol.

I didn't really notice any power until recently when I changed the distributor, something must have been wrong with the old one. Now I need to decide if I should go back to the Edelbrock 750 cfm carb that was on it or stay with the 600 cfm carb that is on it now...

You may feel dumb, but that's cause for celebration, actually! But I hope you didn't put an aftermarket 318 small port intake manifold on it, didjya?

Better to feel like an idiot than to be one. You're doing okay. I order a lot of my parts for my 408 and tell them it's a 318. It's easier because they look it up by application and they always say there is no 360 in your year. It was originally a 318, so I let them feel good about themselves.

you would think that summit racing would have one mopar guy, one chevy guy and one ford guy behind the phone. I know they got it right eventually BUT, only after your insistence. Yes they do have a lot of different parts to keep track of but would it be that hard to hire a "go-to" guy that knows the basics about Mopars. Yes a 340 balancer will work on a 360 "IF" the 360 is internally balanced. Only us Mopar guys would know that it seems. I think summit racing is a great, one of the best even to get parts from though, dont get me wrong. Just venting I guess....In the end, you just got to know what you want and know your stuff and then tell them what you want. YOU DID GOOD!! Congrats!