Best cylinder heads

[Bradness]

I know the issues but would like some opinions regarding the use of oval port 3.0 heads vs. 2.5 split port heads with 3.0 valves & seats. Believe the most common/easiest method is to use the 3.0 oval port heads. Better oil drain back, valves & seats already correctly sized and in place, etc. SVT heads have the advantage of being Extrude Honed. I am not considering the use of early 3.0 heads with the externally driven H2O pump.

Any one flow benched the 2 back to back?

[DemonSVT]

Why would anyone contemplate using the POS 2.5L head design? (my anti-2.5L head soap box ) Even if you fabricated some large copper external return drains and ran an Accusump they are still inferior to the oval (tumble) port design. Plus you would have to spend money to swap over the valves as well.

Yes someone did back to back flowbench tests. The untouched oval port heads surpassed a fully tricked out split port set in flow velocity and air density. (i.e. the two most important areas) The info should be in the old forums. This is beyond the fact that, by design, the tumble port design is superior in swirl and cylinder filling ability. (hence the afore mentioned results)

[warmonger]

I didn't see the air density results. I wouldn't mind checking those out.

[Bradness]

Why would anyone contemplate using the POS 2.5L head design? (my anti-2.5L head soap box )

Never asked him why, but I do know of a NECO member who did re-use the split port design and he claims they're just as HP/TQ productive as oval ports. And yes, he went to the trouble of removing the old seats and valves and putting in the 3.0 parts, and then had them P&P'd.

What effect (if any) does the IM setup have?

[warmonger]

If you go to the trouble of P&P the 2.5L heads with 3L valves then there is plenty of flow potential.

It is just easier to use the ovalport heads for work/cost. If you have the time then go for the 2.5L heads.

[drivebymashing]

what makes more power
the 3.0 block with svt uim and lim with 3l heads
or the full 3 oval with all 3l parts

[Pale Horse]

The general consensus there is the first setup mentioned. Though both setups are better than the original. But now that the "Head Issue" is back on the table. Does any one know of some one Extrude Honing the 3L heads? Albeit an expensive endeavor, but would it be cost efficient per the expected gains? I'm sure this would only net a few ponies/lb.ft., but how would volumetric efficience be overall on this type of setup? I would imagine that due to the swirl and cylinder filling being great on the Tumble Port design, it could only benefit with the better flow characteristics. Am I wrong to assume this?

[Big Jim]

You could accomplish very nearly the same effect with a port and polish.

[TRicker]

is it possible to put a set of 3L heads on a 2.5block? that would make my life so much easier....lol.

[cuda06]

think of a mushroom, that would be your cylinders with a 3l head