ORIGINAL: greg97svt

That's a little bit too generous. What tranny do you have?
For a manual 15% loss means 390/0.85=460
For an auto, 18% loss means 390/0.82=475
Unless you calculating your HP the SALEEN way?[sm=hail.gif]

ORIGINAL: 05 Mustang

498hp @ the fly, 430rwhp ---on a mustang dyno



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ORIGINAL: fordfanboy

It's not that the stock guides will stick a valve and you don't neccessarly have to use bronze but most of the builders out there do. The bronze guides are prone to some oil leaks over time but hold up a lot better in high rpm applications.

The main thing is after a port job, the stock guides are ground down and are too short for the valve stem. They also tend to be a little 'jagged' after porting and once you replace them, you are suppossed to go in and 'roll' them. This is the process of rolling over the edges of the guide to prevent any catching or 'sticking' as it called. The procedure allows the guide to have play a couple ways but prevents play the other way to smooth the motion when combined with the pistons and clearance.

I bought my heads from a company and they did not replace the valve guides. They left the stock guides grounded down and jagged. It caused the valve to stick and tapped a piston - it wasn't pretty after that...lol

The only good news is that company is eventually going to pay for that engine and my new one...

Livernois is making my new heads right now. I already have the shortblock done and will finish it off when the heads get here in a week or so.