Hello everybody , hope you can fix my mess . I am currently working on my 400 small block chevy with stock " pink " 5.7 rods & stock 3.75 crank . My problem is it had a isky rr 505 t roller cam ( 530 lift 290 duration ) in it & i got a crane 118131 roller ( 580 / 600 lift 282 / 290 duration ) to put back in . I checked the crank to cam clearance & seemed to be fine with old cam , so much room the coat hanger i was using would fall through with no problem . So when i put in the new cam , i thought no problem . WRONG ! The cam hits hard . So i pulled the offending rod bolt out ( #1 ) thinking that was it . WRONG ! The cam is hitting the rod . So am i screwed or does crane make a small base circle cam that small to clear this mess ? Any & all help would be great !

a buddy of mine had the same problem with a comp roller cam.he returned the cam to the local shop where he bought it and after speaking to a comp company rep they (comp) agreed to send him a reduced base-circle roller(custom ground) with the same specs for a $5.00 fee. (no charge for the reduced base-circle version.)hows that for service? ;)

Retard the cam 4 deg if you can't return it.
Mine fit after I did that.

Had the same problem with my 383 on a cam swap.
Specs were so close on the 2 cams I didn't even check the clearance. Got to lashing the 14th valve when I ran out of room.
Turned out the swap from 112 to 110 was almost all on the exh side.

Well , Scott , no such luck . I just got done trying that & went as far as going 8 degrees retarded & still hit :mad: . Guess i will have to call crane & hope for the best . Thanks for the help !

chevelleshack, glad to see this post. i intend to switch to a crane hyd roller myself and have been trying to find out what problems would be encountered (see post: "how much pain.."). did you get a small basecircle style and you still had this problem or did you get a regular basecircle and that is why it doesnt work? is the isky basecircle smaller than the crane or is there something else in the geometry of the cam that seems to be causing the problem? please keep us posted on how you resolve this. BTW i am not surprised to hear what Comp Cams did to help that other guy out. they are a real CLASS outfit.

Here are my uneducated calculations & i hope someone can make sense of them . The cam i got was just a standard cam , not small base . I had measured the old cam with a coat hanger ( approx .085 ) between #1 connecting rod & exhaust valve lobe , had plenty of room but that was before i looked at the timing chain gear . The cam had already been retarded 4 degrees. So i put in a 0 degree shim & checked again . Just barely cleared the .085 . But of course , this was after i found out the new cam would not fit graemlins/clonk.gif . Also something i found interesting , the old isky cam looks like a standard cam , ie: cast iron , small lobes ( compared to the crane ) & lobes not nearly as wide . This engine had been built back in the very early 80's & never fired , has roller cam configurations changed that much ? I'm sure they have but it still looked odd to me , didn't know roller cams were built from cast at any time redface.gif , don't have to run a brass gear with this one ?The base circle on the isky is .947 while the crane is 1.050 . Also , the guy at isky said if it was a small base circle cam it would have SBC stamped in it , which this one does not . Also ,if i understand correctly , to figure base circle , take toe to heel measurement & subtract actual cam lift . If that is the case , those are the measurements i came up with . But what i don't understand is that it is not the base i am having trouble with , it is cam lift itself . Some one is going to have to draw a big picture for me on this one ! Anyway , i am going to contact crane tomorrow & see if they can help me out with a smaller base cam or if i will have to stay with the cam i already have . I will let you know .