ST or BT 20v for 7AGTE Build? Keep vvt?

**PRIMRK** · 13-09-2010, 01:32 PM

Hey All

Ive got a ST 20v with quads here, want to know befor sticking it on my 7A short if the black tops are realy better in this application, Ive had a few people say that the ST are better for boosted application, true or false?!? If False are the black tops that much better, dose it warrent me goin out and finding one?

Also should i keep the vvt? its a track only car so economy isnt going to bother me too much, thinking about getting some of those toda adjustable cam gears to replace the vvt ones with (will also make it easy to do the timing belt on the 7a -> 20v)

Any info will help make up my mind.

**RT40Corona4AGTE** · 14-09-2010, 05:34 PM

this is what I have been told by a very reliable source. . . . . .

"The ports are totally different to the Blacktop and the ports are alot smaller.

The ports are higher and the combustion chamber is different, all the angles are totally different and not ideal. They rectified all these issues in the blacktop head and hence the blacktop head flows very well.

The intake of a silvertop will flow around 165cfm where the blacktop flows 210cfm on the same flow bench."

So it is your call really, I too already have a silvertop head and thus, am using it for my 4A build. It will be interesting to see what others have found too, though I trust in the above.

**shrike** · 14-09-2010, 05:49 PM

If your going to pay for head work you can start with either however depending on application it may take more labour for a silvertop

**PRIMRK** · 14-09-2010, 11:23 PM

Ill be getting as much head work done as possible (my dad believes the head makes or breaks the engine so...his paying for it, not that his wrong). I have had people say that once the head has had a bit of work dont they are about the same, true/false?

Ive had a lot of people say that the ST are stronger than the BT but i think every one was just talking about the bottom ends?!? This wont affect me as im going to be using a 7A bottom end with forged goodness. Is there any real diferance in the heads strength?

**trdee** · 14-09-2010, 11:26 PM

they were talking about the bottom ends, namely the conrods. strength isnt an issue with any 4AG head

**Bazda** · 27-09-2010, 11:49 AM

Short Answer, the BT head will win all over the ST head.
BT head flows much better in stock form. And VERY good if you get the right person to port it. People still say 16v heads are better for porting because no one really knows how to do the 20v head.
And yes use VVT, a huge gain when spooling the turbo up. I think it gained about 60 kw atw at a certain rpm on my car.