head skimming for performance? cam to suit?

[Rob]

whats a good amount to skim from a 517528 head on a 2000 mk2 flat top block?

and what cam is good for waking the motor up? gt6 or something more spicy....

[david_lall]

Why would you want to increase the compression ratio any more?

I always understood the standard 'S' head to be the one worth using for performance and why not put the TR camshaft in?

[Rob]

the car is always run on 98 octane. im looking for a bit more go.

s heads are unavailable here in oz, and tr cams command a premium. and id like something with a nice lope to the idle.

[englishbull]

As David

says......................S head is fine as is and you want the early PI cam...........

[TedTaylor]

Trouble with an 'S' (also TC) head number 219016, is that they are at a premium in the UK let alone OZ

Basic gas flowing of an 'ordinary' head to a blueprint type spec and skimming will give a lot of help. As for camshafts read Chris Witor's info on his website http://www.chriswitor.com for a guide.

Contact Andy Thompson in Oz for some help as to what is available?

Ted

[Mike Stevens]

The standard 'S' head on a 2.5 gives only 8:1 (8.5:1?) CR. On a 2000 with flat top pistons it'd be even lower.

I did this on my 2000 some time ago. I used an 'S' head and had it skimmed. I aimed for ~9.1:1 but I've kept the standard 18/58/58/18 CAM but with twin HS6s. The early PI cam (same at early GT6) at 25/65/65/25 is also nice in a 2000. After all, it works OK on a GT6 albeit it bit lumpy at tickover!

It's not difficult to calculate how much to skim. But as Ted says, there's a lot of info on CW's site.

Cheers,
Mike.

[Alan Chatterton]

(post on behalf of Andy Thompson, I think he put it in the wrong section!!!)



So the engine is a 2000? What induction exhaust are you considering as it is as important as the head and cam.
Assume it will be manual?
If it is an early head it should be 3.300" thick and will only need a light skim to match an uprated cam. They are a good head but need checking for cracks between the valves - best do that before spending any money on it.

_________________
Perth WA
1970 2500PI estate
1964 2.7PI saloon
1973 2100 EFI Megasquirt
1972 Stag

Very Big garage

[Rob]

engine is a 2000. has been port matched on head and inlet. will be buying 6-3-1 and getting a single box 2 inch system. will be staying strommie for now but looking at r1 motorcycle carbs at xmas. had them on my volvo. its an auto but i have a full manual setup aswell. would a gt6 cam work?

[Andy Thompson]

engine is a 2000. has been port matched on head and inlet. will be buying 6-3-1 and getting a single box 2 inch system. will be staying strommie for now but looking at r1 motorcycle carbs at xmas. had them on my volvo. its an auto but i have a full manual setup aswell. would a gt6 cam work?

Yes an early PI cam is very well suited and not nutty. 308778 scribed on the cam normally - they last very well so might be able to find a good S/H one.

You really need a manual box and HS6 manifold and carbs to make it work. Early inlet has starved cylinders 2 and 5

[Rob]

my parts car uses su carbs as its a 74.how do i identify hs6's? cheers.