Elite Marine

I'm in the process of reassembling my engine and installed Comp Cams 4806 guide plates per the recommendation of the head Mfg - Dart. The previous set of Manleys were cut and rewelded to correct the geometry of the valve train. The Comp Cams appear to work on all but (2) valves - #3 and #2 cylinders.

Which is better, slot the mpounting hole for the play to move the guide or cut and weld the guide?

Any other ideas?

paradigm shift

Do not know how yours are but mine would not line up other than cutting and rewelding guide plates. Slotting would not do the trick. Depends if both guides are off. Mine only needed to move one side if that makes any sense.

formulaF302

I had the same problem and used guide plates from GM for a 427.....that took care of it. I don't have the part number around but got it at the dealer....

formula31

??, Ive never had any problem with guide plates. Are you saying the slot did not line up the pushrod with stud and valve? Have I just been lucky?

hangem out 2dry

I HAD THE SAME PROBLEM ON A SET OF DART HEADS ON 540 MERLIN TALL DECKS.I TRIED COMP PLATES AS DART RECOMENDED BUT THEY WOULDN'T CLEAR. I TRIED EVERY BRAND PLATE I COULD GET MY HANDS ON BUT THEY WOULD NOT LINE UP. I HAD TO END UP GRINDING THE HEADS FOR CLEARANCE.IF YOU GRIND THE SLOT IN THE GUIDE PLATE WIDER IT TAKES THE HARDENED FINISH OFF OF THE SURFACE AND WILL CAUSE PROBLEMS DOWN THE ROAD.

paradigm shift

My problem was rocker arm not centered on valve stem. Nothing to do with length of pushrod.

formula31

Yea, thats what I meant. Length is a whole other issue. Ive used Merlin heads and mostly GM and never had that problem. ??

PatriYacht

I've got Merlin heads. My engines will be out in about a week. I can see what guideplates are in there then. Like formula 31 said, I've never had any problems. Don't Merlins use stock Chevy parts and geometry?

Offshore Addiction

I would have dart address this issue or have them refund so you can use a set of merlin heads,there an extremly large company and should have come across this issue prior,maybe talk with someone ther politly who has more experience or who does there R&D....relieveing the strenght at the slot is a questionable situation,then again you may have to cut and weld 6 or 8 guide plates to get on exactly were you need it,and slotting the mounting hole is a direct risk due to the fact your also moving the location of the second pushrod on the plate,dart has sent new sets of heads to us prior when finding out there were casting problems,they seem to be great people and know what your trying to acheive.....

formulaF302

dunno what to tell you.....thats just the way mine worked out after I reconfigured my pushrod lengths and had the new pushrods in....maybe I got a bad run of the comp cams guide plates....it would'nt be the first time they had bad runs of parts!!!! (like lifters for instance......)