2000 Merc 5.0 performance heads

[SenseiJ]

Hey folks.
I'm getting performance heads.
I need to decide between these two...

SWP NKB 274s @ $790 assembled
60cc chambers
190cc intake runners

or

AFR 185cc enforcers @ $1047 assembled
Combustion Chamber Volume (cc):59
Intake Runner Volume (cc):185cc
Exhaust Runner Volume (cc):64cc

numbers are similar, both will be huge improvements over my stock gt40p's.


impressed with SWP and their attempt to show the quality they provide.
obviously afr doesnt REALLY need to do that since they clearly do well, well known, etc.

anyone have any input?

 

[410Fortune]

AFR has a good name for themselves

I am sure you are running some sort of header correct?

 

[CDW6212R]

Those Skip White heads sound great if the quality is there and they are as listed. 245-260cfm at .500" and .600" lift are very good fuges for the $800 price.

I have Flotek heads that are 180cc and should be a 235cfm head given the clean up porting that Thumper did in building them. I gave $850 assembled plus over $200 for custom cam valve springs(very important).

If you have a proper header that will fit normal SBF heads, I'd try the SWP heads, but I'd pay extra for the valve springs wanted by a cam designer(not the Comp Cams tech line guys for example). A real custom cam is better partially due to special valve springs, which can handle the best valve ramps etc.

 

[SenseiJ]

I will be making custom headers with 1.5" primaries ultimately to a single 3.5" out.

The savings between the 2 will almost pay for the cam in which the springs on either one will support according to threads I've found and a little math.

According to the flow numbers both head options should support over 400 crank hp. . .?

 

[CDW6212R]

Make the primaries 1 5/8" at the least. 1.5" pipes are fine for bone stock small V8's, not for any performance uses. Don't try to snake the pipes around to gain length like for an equal length header. That's what TM headers are and they are terrible to install. If they were a proper size, I could support the horrible install process, but given the mediocre airflow of 1.5" pipes, they should be larger for sure.

Lastly, install two mufflers, there is a ton of space back there for them easily. Two mufflers flow twice as much as one, that's elementary basics.

 

[SenseiJ]

Make the primaries 1 5/8" at the least. 1.5" pipes are fine for bone stock small V8's, not for any performance uses. Don't try to snake the pipes around to gain length like for an equal length header. That's what TM headers are and they are terrible to install. If they were a proper size, I could support the horrible install process, but given the mediocre airflow of 1.5" pipes, they should be larger for sure.

Lastly, install two mufflers, there is a ton of space back there for them easily. Two mufflers flow twice as much as one, that's elementary basics.

my theory . . .
for an n/a 302ci stock stroke under 400hp 1.5 will work. that 1/2" (1/8" times 4) of potential space i'll save may help in routing. i'm entertaining the idea of 180 degree headers, mainly for fun, and want them to lead to a single pipe exit. another reason for single setup is it's essentially half the price but will still flow enough for my arrangement?

anyway...

looks like i'll give SKP a shot, but will buy the heads closer to finish as they have a 1 year warranty and don't want them sitting around for a few months after buying . . .

 

[mrjody]

Don't be scared of the small 1.5 primaries.. they flow very well with a little work..