Ok of my limited knowledge in the head area this is what i got.

Manley valves are of the same quality of the ferrera but the valves are actually a tad to big for LT1 heads

Ferrera more expensive but has the right fit 2.00 in/ 1.56 ex.

I think the manleys are 2.02 in/ 1.57 ex ?

The LT4's are 2.00in/1.55ex.
The intake stems are hollow to save on weight and the exhaust stems are sodium filled for heat transfer, they are also lighter than the lt1 exhaust valves.

If price wasnt an option and you were to use them with ported LT1 heads which would u pick?

 

Do the LT4's have undercut stems?

 

Combo and advanced induction seem to be going with ferrara.
Seth told me why, but i forgot

 

All of these companies make the correct size valves (2.00/1.56 or 1.57)

Ferrea 6000 series will flow the best and tolerances are always close.

Rev valves are pretty good as well and a lil less $$$.

Manleys are even less $$$ but still flow better than the LT4's

The LT4 valves are VERY light but probably flow the worst out of the valves listed.

If I already had some of these valves in the coprrect size, I would use them. If I had to buy some, I would buy the Ferrea's or Rev's before the others. The LT4's would probably be pretty expansive unless bought used.

NightTrain66

 

Thanks Lloyd thats what i was looking for.
I need to hurry up and take this heads off and send them to you....
Seems like everything is getting in the way of that lately.... soon... soon.

 

I bought the Manley Race Flo valves. Jegs has them for 10.99 a piece. Seem to be working well but then again something else may work better.

John

 

What about SI Valves?

 

I'd listen to Lloyd, he knows this stuff.

Rich Krause

 

I've got Manley 2.0"-1.56" "Pro-Flo" valves in my LT1. I bought the valves before I sent the heads to my porter, and originally he didn't want to use them because he usually uses Ferrea. After putting the Manleys in and getting 271 CFM @ .550" even he was impressed.

Frank