E-Bodies.org Cuda Challenger Forum

Technical Shop => Engine, Transmission & Rear End => Topic started by: Rbob on January 13, 2021, 08:30:23 AM

Title: T/A Rocker Arms
Post by: Rbob on January 13, 2021, 08:30:23 AM
I know they are offset but I thought they were a 1.6 ratio, I cannot find any info saying what the ratio is.

Does anyone have knowledge of this?

Title: Re: T/A Rocker Arms
Post by: MOPAR MITCH on January 13, 2021, 11:42:13 AM
Both T/A rocker arms are 1.5: 1 ratio.  In fact, for the exhaust, some people will substitute the 273 v8 rockers (less robust as the T/A, but same ratio).
Title: Re: T/A Rocker Arms
Post by: Rbob on January 13, 2021, 01:00:46 PM
Thank you, Mopar Mitch,  good to know. 


I just mailed them to Rockerarms Unlimited, somehow they have been abused.

http://rockerarms.com/ (http://rockerarms.com/)
Title: Re: T/A Rocker Arms
Post by: MoparLeo on January 13, 2021, 11:37:29 PM
The rockers on the roller Magnum series engines from 88-03 had 1:6 rockers.
Title: Re: T/A Rocker Arms
Post by: MOPAR MITCH on January 14, 2021, 11:45:05 AM
Rbob -- I recently used RockerArmsUnlimited (Spring of 2020) to recondition my T/A rockers... and improve them for racing usage.  They did an excellent job... high quality!  Excellent service!
Title: Re: T/A Rocker Arms
Post by: 68bee on January 14, 2021, 03:52:11 PM
What did they do to the rockers and how much did it cost
Title: Re: T/A Rocker Arms
Post by: MOPAR MITCH on January 15, 2021, 12:13:02 PM
They added bronze bushings, new adjusters, polished/cleaned, slightly narrowed the side faces for allowance of serrated shim washers (for better on-center alignment over the valve tip)... and less drag between the rockers.    I forget the exact cost... ~$450 if I recall.   I also sent them the shafts (new from Hughes with slots) so they could properly fit them with the bushings.

Make certain you talk with Gary at RAU... he's got a wealth of knowledge to do things right.

Pending your valve spring retainer-to-rocker arm clearance, you may have to slightly grind some extra clearance... you'll have to assemble and visually inspect that on your own for each rocker arm.
Title: Re: T/A Rocker Arms
Post by: Rbob on January 15, 2021, 01:21:52 PM
Surfing internet today and found some info on offset rockers that may be of help to someone.  Indy Heads used 440 rockers as the offset rockers on the 340 t/a head.

I do not know if it would work but it may.

Title: Re: T/A Rocker Arms
Post by: 68bee on January 19, 2021, 05:12:09 PM
Quote from: MOPAR MITCH on January 15, 2021, 12:13:02 PM
They added bronze bushings, new adjusters, polished/cleaned, slightly narrowed the side faces for allowance of serrated shim washers (for better on-center alignment over the valve tip)... and less drag between the rockers.    I forget the exact cost... ~$450 if I recall.   I also sent them the shafts (new from Hughes with slots) so they could properly fit them with the bushings.

Make certain you talk with Gary at RAU... he's got a wealth of knowledge to do things right.

Pending your valve spring retainer-to-rocker arm clearance, you may have to slightly grind some extra clearance... you'll have to assemble and visually inspect that on your own for each rocker arm.

Thanks for the information
Title: Re: T/A Rocker Arms
Post by: MoparLeo on February 16, 2021, 11:38:36 PM
The Indy head is using a 440 rocker because they moved the rocker shaft over to align with the larger port. The rocker is aluminum and because of the much wider face, they can off set the adjuster in the rocker arm. Not a bolt on for a T/A.