Posted By: elmor
73 440 HP balance question - 03/31/13 08:41 AM
Trying to find out if this engine was internally or externally balanced from the factory. It has the small forged crank harmonic balancer on it now, but did it come from the factory like that? I keep hearing if 6-pak rods were used it could have a weighted balancer. Needless to say, I'm confused. Too much grey matter damaged in the 70's and early 80's! Help!
Posted By: Dodgem
Re: 73 440 HP balance question - 03/31/13 01:31 PM
till late 73 440 forged crank were the majority with stock 440 rods and balancer. although some were forged with six pack rods and need the extra offset weighted balancer,
My guess is you have a steel crank neutral balance. what does the crank look like?
Posted By: 72roadrunnergtx
Re: 73 440 HP balance question - 03/31/13 05:13 PM
’73 440 HP-forged crank, HD rods, and ’73 low compression pistons equals full internal balance, no counter weighted damper or flywheel/TQ. Only the ’70-71, a few ‘72s, high compression piston/HD rod combination (six-pack motors) had external balancing with a forged crank originally.
Posted By: John_Kunkel
Re: 73 440 HP balance question - 03/31/13 07:34 PM
According to TSB 09-01-73C Dated October 11, 1972 "The 1973 standard 440 engine will be built with either the forged or cast crankshaft."
Posted By: screamindriver
Re: 73 440 HP balance question - 03/31/13 11:28 PM
Yep, I have a 73 440 HP with a forged crank,small balancer and the heavy rods...Yanked it out of a Pa state police car...And I've also had a standard 73 440 with a cast crank...Seems 73 is a roll of the dice on what you get...
Posted By: elmor
Re: 73 440 HP balance question - 04/02/13 11:42 AM
Thanks guys. Guess I just have to get it up in the air and pull the pan. Even then I'm not sure how to tell the heavy rods from standard rods. I have to check and see if it has a weighted torque convertor in it as well. It's installed in a 77 D-100 swb. I bought this thing a couple of months ago and I'm finding out that the seller wasn't upfront with me about everything. He told me that it had an aftermarket .496 lift cam, and from what I can see, it doesn't look like the timing cover has been off the engine in 40 years. I keep finding things that don't add up or have been Mickey Moused on this thing. It seems to run well, but I can feel a vibration at low speed upon accelerating and decelerating. Also, at an idle in gear, the truck kind of jerks and bounces when you take your foot off the brake and let it idle forward. It's frustrating to say the least.
I didn't seem to notice a lot of vibration at speeds above 30 mph.
Posted By: dogdays
Re: 73 440 HP balance question - 04/02/13 04:59 PM
If you get so far as to be able to see the rods, the standard 413/440 rods have 535 as the last digits of the forging number and a big LY on the other side near the big end.
The heavy rods have a forging number ending in 908.
R.
Posted By: JohnRR
Re: 73 440 HP balance question - 04/02/13 06:00 PM
Having the big rods does not guarantee it being external balance. I internal balanced a big rod/trw 1.990 piston and a very small amount of steel , not mallory , was added to do it . And I have read where some motor home engines had big rods , low compression with forged cranks and internal balance ...
