Ok... here's the deal. I have a comp cam XR288HR retrofit cam(236-242/.520-.540/100 lsa) which i was going to put into my 383 along with the retrofit hydraulic roller lifters.. which are absurdly expensive at nearly 500 bucks.

Now from a cost/benefit point of view.. I am beginning to have second thoughts, and am considering running a mechanical cam and lifters(which are about half the cost).. but I will have to change my valvesprings. So... is it ok to run my 3/8 stud/roller rockers with a mechanical cam given the increased spring pressure, or should I go to 7/16?? Or can i just slap on a $100 3/8 stud girdle from moroso and call it good?

Questions? Comments? Opinions? Hate?

 

So you wanna run a solid roller right?

 

I am highly considering it.

 

...

 

How much lift and spring pressure are you talking about here?

 

I would run the comp cams 977 valve spring which has a 155# seat pressure at 1.85 install height and a 441 lb./in. spring rate.
The cam I am looking at is a Comp XR274R (274/280-236/242-.564/.570-110) mechanical. Another problem arises though with this.. considering that the 977 springs are only good for 600 max lift, and i would be at 601-608 with my 1.6 rockers. I believe this could be remedied by having an install height of 1.9" with 133# seat pressure, and considering I am running titanium retainers.. I dont believe I would have a problem with valve float.

Also if I do run and install height of 1.9"... that would open the door to the next size cam being the XR280R(242-248/.570-.576(.608-.614 w/ 1.6's)).

 

FYI I am currently running the comp 987 spring which has a 121# seat pressure at 1.80" install and a 344# spring rate.

 

Anyone have any ideas?

 

well i was inclined to post earlier today and say you'd need 7/16 but i don't know for sure and haven't looked.