Heads / valve question

[TurboJames]

hey guys, some might know but I have a 4.1 (252) with the stock 3.8 heads slightly ported on. My question, would the heads have a sufficient enough air flow for this motor? I am leaning towards a no, but is why I'm asking lol. Also, would there be a upgrade needed in the valves and such? If so what would be the best kind.

Thanks a lot as always

 

[WarWagon]

4.1L & 3.8L RWD engines used the same heads. Stock valves are OK as long as they are usable, you can use stainless valves and the intake valve can be oversized.

 

[johnplogii]

Flow enough for what goal? Iron heads can go pretty far. Aftermarket aluminum heads are obviously better and can flow quite a bit more.

 

[TurboJames]

Well, I would to run some 10second passes. I'm debating whether getting my heads fully ported and polished and possibly new valves? Would the money be worth it for the amount of air that it will let in?

 

[johnplogii]

Probably, depends on what was already done. They might be good enough as is.

 

[johnplogii]

The area that needs the work is behind the valves

 

[TurboJames]

My engine guy told me someone tried to port them already, so he cleaned them up for me. No exact measurements or flow tested. So I'm wondering what I should do here. I have few extra stock heads as well. Would bigger exhaust valves be better? Or maybe some unshrouded valves?

 

[johnplogii]

Most do a 1.77 intake valve which is slightly larger and run a 1.50 exhaust valve which is the stock size.