Input on what you are doing for refurbishing valve guides and who to trust doing them? First time these heads will be getting any new parts. Dart 355 CNC. Midwest/Great Lakes area?

I wouldn't put liners in bronze guides...Just remove the old guides and install a new set....Liners are fine for stock rebuilds...

IMHO of course

I understand Dart castings are considered a "light casting" and a CNC'd unit is going to be thinner yet. BBC guides are pressed out and in and seal the water jacket. While not Dart castings, I suffered a cracked exhaust port wall after replacing guides on a ported casting and then torquing down the heads. Not trying to be a Debbie Downer just a heads (no pun intended) up on potential gremlins. I paid the price, no charge for the info.

Either will do the job. I would see what your machine shop is more comfortable doing though. With stock heads the guides aren't concentric so lines are better.

Liners are for Iron heads with cast guides.

If I have a head that the guides aren't contoured to the guide wing, I will put new guides in.

If the head has been CNC'd and it's all contoured, I will put a liner in it.

With that said, I have hundreds of guides out there with a liner.

Thanks for the comments/opinions. Any remarks of who will do them right? Don't want the valves sunk trying to fix an off center replacement. Everyone seems to agree that a liner will hold the original placement. TIA

quote:

Originally posted by bry-war:
Thanks for the comments/opinions. Any remarks of who will do them right? Don't want the valves sunk trying to fix an off center replacement. Everyone seems to agree that a liner will hold the original placement. TIA

If you need guides, you need a fresh valve job! Also, you should look at why you have bad guides.