[ta man]

For a basic 9.25 to 10.2 to 1 Compression 455 with mild flow numbers it still hard to beat a 041 or 60919 Crower with Rhoads setup...it just plain works...Maybe somebody should post all the "Jim Hand Articles" on a sticky here for the newbies!

[77 TRASHCAN]

Originally Posted by ta man

For a basic 9.25 to 10.2 to 1 Compression 455 with mild flow numbers it still hard to beat a 041 or 60919 Crower with Rhoads setup...it just plain works...Maybe somebody should post all the "Jim Hand Articles" on a sticky here for the newbies!

Amen to that!!!
I wonder if maybe 10.5:1 might help w/ the idle and allow the use of conventional lifters w/ the 041 cam..

The 041 might not be the best for all combinations, but compared to XE cams....

[ponyakr]

Here's a few I Googled up right quick. Don't have a clue how to find all of 'em. Some links I found no longer work.

http://www.pontiacsonline.com/Jim%20Hand.htm

http://community.fortunecity.ws/silv...build/cams.htm

http://www.dapa.org/drag-racing-with...modifications/

http://www.pontiacstreetperformance....ld455jh99.html

http://www.pontiacstreetperformance....455jh2006.html

http://www.pontiacstreetperformance....ockerArms.html

https://home.comcast.net/~ericdouthitt/compression.htm

[ponyakr]

"...I wonder if maybe 10.5:1 might help w/ the idle and allow the use of conventional lifters w/ the 041 cam..."

I wouldn't even consider using the 041 with reg lifters. You lose too much vac and smooth idle. IMO.


"Variable or leakdown lifters are designed to lessen the cam duration and lift at low engine speeds by allowing more oil leakage within the lifter body while the lifter is under valve spring pressure (on the cam lobe). As the leakage is a function of time, the lifters leak the most at low rpm, because there is a relatively long time during the lift cycles. This allows the Rhoads lifter, with its machined leakdown groove in the body, to shorten the lobe duration by 10 to 15 degrees and reduce the lift at low rpm.

As the engine speed increases and the cycle time becomes shorter, less leakage occurs. At 3,000 to 4,000 rpm, the actual leakage and the effect on cam timing become inconsequential. The dramatic increase in vacuum and low-end torque provided by these lifters more than offsets the slight loss of upper-end horsepower in a heavy, automatic-equipped vehicle, such as my wagon. The overall result is the ability to use a fairly radical camshaft to maximize mid-range and top end power while developing strong lowed torque.

Additionally, a variable lifter will operate to a much higher rpm before it begins to hold the valve open due to lifter pump-up. The weight/viscosity of the engine oil used will have a significant effect on leakdown lifters. The thicker the oil, the less pronounced the leakdown eject becomes.

It is neither necessary nor advisable to use Rhoads lifters with a streetable cam such as the 068, because the cylinder pressure may rise too high at low rpm, causing detonation or pre-ignition. There are benefits and disadvantages in all types of variable fibers, but the Rhoads units provide the best overall performance in my wagon.

...only a direct comparison test, such as conducted with the wagon, would prove that the 041 with Rhoads lifters is clearly a better performer than this typical non-Pontiac-grind cam with Rhoads lifters.

It was beginning to appear that Pontiac Engineering might actually have known what they were doing when the 041 was designed." (Jim Hand)