I have just started my 0.040" over 455 recently with the HT2148 and spider setup. Going easy for awhile breaking in and playing with ignition timing.
My issue is I have HS roller rockers 1.65 ( really 1.69-1.70) ratio, and did not want to replace them. My current head / valve / retainer setup calculated to a safe .570" lift.
All the recommended roller cams would not work with my rockers. I had a cam speced as follows from Ed at Flow Tech.: (I believe Comp Cam intake # 3052 intake , 3053 exhaust), 230 / 240 deg at 0.050" lift, 0.320 cam lift for .544 valve lift. 114 deg LSA installed at 111 deg. Base circle measured 1.189". About 0.030" clearance between the lifter and spider.
Thankfully I still have a Mopar offset key kit # 4286500 to degree the cam properly.
Had to relieve grind the dog bones, with #7 requiring more grinding to get the dog bone perpendicular to the lifter. The other trick is the amount of bending of the spider so it applies sufficient pressure the the dog bones. That took a few rounds a "bend to fit". I applied oil to the setup and rotated a multiple time to ensure the bones were not bind on the lifter, rise up and remained flat. Of course bought a pushrod checker to order the correct length.
I will report back as I plan to have to tested on a DynaPack dyno to compare to my modded '04 GTO.
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