Question for head gurus
 

Assuming a 450HP NA BBC engine, are inconel exhaust valves NEEDED. I know it is safer but is it really needed? Also, how about valve guides. Are bronze guide LINERS enough or do you need SOLID bronze quides? And last but not least, what about reduced neck valves? Are they a no-no even if they are one piece?

Trying to learn new stuff.

formula31,

As you know I'm certainly NOT a head guru, and don't know much about the solid bronze guides vs the bronze liners, but I will give you a testimonial as to what I am running in my Dart aluminum heads that JimV had set up for me that have not failed me yet. I am using the solid bronze guides, Ferrea stainless one piece valves that have the 11/32" stems and the exhaust valves are NOT the inconels. Jim told me in most cases he does NOT use inconel valves and that they are NOT NEEDED on naturally aspirated engines. On a blown engine application it might be a different story though. I will let him and any of the other experts speak for themselves, but Jim even runs his own heads the same way if I am not mistaken. If it was a problem I think he would have been doing things differently a long time ago.

If I remember correctly, what JimV said was the inconnel valves were hard on seats and therefore he didn't recommend them except in the most demanding (blown) applications.

The general OSO consensus I got a couple months ago on this was Severe Duty were fine for NA engines. That is what I did. Don't know the verdict yet on mine though, so just relaying others expereinces. I think a lot of it has to do with driving habits. If you are a WOT kinda guy, I'd go with the inconnels (or ferreras). Not enough seat time for the cooling process at WOT. If you are a WOT is short spurts sort (like I) Sereve Duty.



BT :cool:

formula 31,
these are my thoughts on your questions. i'm sure some will disagree but to me inconel is not mandatory. cast iron guides are more durable that solid or sleeved bronze. sleeved are ok though. just make sure your valve seats are re-machined after installing any new guides. reduced neck valves don't help a lot with flow. they help with weight reduction so are easier on the valvetrain. inconel is heavier than stainless too.
BT for president :crazy:

Fran

Thanks Hillary :bunny:

BT :cool: