Lifters for aftermarket Pontiac block
 

Anybody have a take on these lifters for an aftermarket (MR1) block:

https://butlerperformance.com/i-2504...tegory:1234801

or

https://www.lgmrnd.com/Black-Mamba-P...p/mrl-6498.htm


These Crowers are only suited for an aftermarket block. Any feedback?

Anyone with real world experience with the Black Mamba ones?


What are those with an aftermarket block running today?

Does the MR-1 block require a taller lifter body ?

Here is the note regarding the IA II block...

"A stock lifter will go in this block. When using high performance roller lifters, the spreader bar may hit the lifter top surface. This surface was raised to add meat to the lifter area so BBC lifters can be used. If using a .200 offset lifter you will need to have the bar raised .300 higher or mill the top of the lifter bores."


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Here's a clue.........

Note this build here by Ken Crocie that used a MR-1 aftermarket block:

https://www.motortrend.com/how-to/cc...-alloy-indian/

Rather than a solid roller cam note this build used a hydraulic roller cam. In conjunction with it he used COMP 857 Retro-Fit Hydraulic Roller Lifters. These are not a tall body design.


Side note- On my current 505 build using the IA II block I used CROWER SEVERE-DUTY CUTAWAY ROLLER LIFTERS
Noted on page 6 here:
https://www.crower.com/media/pdf/RollerLifterGuide.pdf

( Note: There is NO notation regarding a "Tall Lifter Bore Block" for the Pontiac application )



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I have "regular" Comp Endure-X solid rollers in mine. No special machining.

Some investigation answers my question in post number two.........

"The MR-1 and MR-1A Pontiac blocks are designed to accept ALL stock Pontiac parts."

"Pontiac roller lifters fit without grinding block (Crower as well as other brands)"

https://www.tinindianperformance.com...engine-blocks/

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is there any additional info on using bbc lifters in an IA2? is there an advantage?

For reference my block is an IA2.

I highly suspect that Butler's note left out 'big cam bore'.

Big cam bore blocks can run high lift and still have a good size base circle on the cam lobes. Base circle enuff that the low oil band, on them lifters, doesn't drop out the bottom of the lifter bores.

Clay

A fwiw, regarding the Crower original full body solid roller lifters the .300" taller BB Chevy lifter is 2 grams lighter than the Pontiac, no big deal there. Their body diameters and bearing diameters are the same. The pushrod seat height is 1.590" on the Chevy and 1.740" for the Pontiac. Both feature the same edge orifice oiling.

Why Longer Lifters Live Longer
https://rehermorrison.com/tech-talk-...-live-longers/

"We recognized that the longer bosses would stabilize the lifters in their bores – a real advantage in big-block Chevy engines with angled pushrods."

Note the angled pushrods in conjunction with the Butler "Wide Port Heads" and the use of their offset rocker arms and offset lifters.

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Next question for the sleuths out there.... is the lifter bore feed hole in the IA2 block located higher up than in a factory block ? Is so what affect, if any, would it have with the use of .300" taller body solid roller lifters ?


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The "+.300" taller" is just the link bar area of the lifter. Not the body itself. It is done for the sole purpose of clearing taller lifter bosses, just like Dart did to the Chevrolet blocks. Oil holes are in the same spot.

Thank you. I got the longer bosses in the block confused with a longer lifter body.


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I'm running Crower 66494X903E lifters in an IA2 block. The link bars are fine. We have the lifter bores bushed. My lifters have a little score cut from the lifter oil band to the edge orifice oil hole in the lifter. Promotes oiling to valve train from what I understand. Not sure it's needed or not.

A comparison on Crower solid lifters. The .903 Endura +.300 taller left, and the .842 on the right. I should have straighten the link bars out.. both are high pressure pin oiling.

I used the Comp "S" hydraulic roller lifters in the MR-1 block. Works fine.