Originally posted by British Banger:
Now one thing that I am wondering is whether or not headwork is really worth it on the svt. David z has big valves, P&P heads, and more aggresive cams, yet he only dynoed at around 5 - 12 Hp more than vadim (sho shop). vadim had no headwork done except for some port matching.
But the Sho Shop car also had larger ported intake runners and bored TB that were both larger than David's, not to mention a dyno at their disposal to tune repeatedly on. In their write ups in MM&FF, Sho Shops had also done EH port matching on the intake side of the SVT heads to match the larger runner ports. I think that for David to out dyno Sho Shops proves a lot about cams and head work. Some offsetting mods in favor of David Z.
Also, the heads that David has have a steel insert under the valve. I talked to Chris R. about them (whom David got the heads/cams from) about getting a set copied since David had already purchsed them. $$$1500$$$ just for the inserts is the first quote I got from a recommended shop. The steel inserts are needed to keep the aluminum head material from cracking between the larger 3 liter valves once the material is removed to install the larger valves in the smaller chambered head.
