[YAT-YAS2141]

289 bored 60 over with the original crank polished, new mild cam, and original heads rebuilt, all done at a machine shop. The engine shakes really hard and i don't know why. Im leaving in three weeks for japan, Im want It to run before i leave, i need some help please.

[Dana W]

You didn't mention your piston & rod setup, what's it like other than larger diameter pistons?

Did the machine shop polish away your counterweights.

Check the easy stuff first. Ign. timing, transposed plug wires, distributor orientation, but you've prolly done all that already, then see if your #1 piston hits TDC when it is supposed to in relation to your #1 valves doin' their thing. You'd be sprized how far off that can be and the engine still starts.

One nasty thing, I had a timing chain stretch and jump a tooth or two on a 72 Gremlin X 304, stupid nylon timing sprockets. The thing idled like a A/A Funnycar, but would not run for snot. I am surprised it even started. Come to think of it, I am surprised it EVER started.

[YAT-YAS2141]

Ive checked those things, i dont know how many times i reset the timing, as far as the plugs go, i got the engine back from the machine shop dropped that and the tranny i and did everything to hook it up, however the firing order was off, i was using the firing order out of the chilton manual, there are only 3 diffrent firing orders ( 6cyl, 351W and everything smaller than 351W), the weird thing is i hooked the plug wires up for the 351 and it fired right up, of course i had to adjust the distributor a little, it runs fine in park and neutral, but when it gets a load it on it it sputters and dies if u u accelorate to much. Thank u for the quick response to really appreciate it.

[thetvirus]

Maybe a broken motor mount or even the transmission mount...?

[YAT-YAS2141]

they were all fine when i put it all back together, what im not undersanding is why the firing order changed because its still a 289 but has the 351 firing order, another idea i heard is that the harmonic balancer could be wrong, the machine shop put an after market balancer on.

[Jonk67]

Your firing order will be based on the cam that was put in, you can install a 351W cam into a 289/302, see if you can find out what model/part# cam the machine shop installed to make sure.

If the engine is actually shaking, like it's running on diesel fuel instead of gas I would suspect that you have mismatched harmonic balancer and flywheel. The weights have to match > both 28oz. or both 50oz., if either is different it'll never stop shaking. Did you have the driveshaft balanced when out? Was anything else changed (rear end, etc.) if you don't have the right pinion angle it'll cause vibration too.
Was a new harmonic balancer installed? correctly? if it's the original or older one the rubber may have allowed it to slip and put you out of time when it looks right.

If it's just stalling and dying I'd suspect timing/firing order, vacuum leak, dist. hooked to wrong vac. on carb. or misadjusted carb. first.
Jon