The V8 Owners Forum -

Does anyone know the spec of these?

I've heard of a few engines now that they've been used on to make some real serious power and wondered if anyone knew anything about them?

Ive heard these described as stage 4, but as stevie pointed out on another thread these stg numbers are pretty meaningless! isnt phil using a 5 ltr TVR in his cobra? if he's using the heads he may be able to advise. About 6months or so ago a set were for sale in the classifieds on here but i think the bloke wanted over a grand for them.

Another thought. Perhaps if you email TVR power they could give you flow numbers, valve sizes, chamber sizes etc.. I'm sure they would if you make like you want to buy a new pair

Speak to Rob at V8 developments as he knows all about them. Demo has a set on his car if he drops by.

Hi there,
I know Rob at V8 development used them on the 5.5L he built, I have a set on my Cobra but havent had them apart. Rob did tell me the valve sizes, etc, but I forget now. Give him a ring.
Phil

Steage 4 as said b4, but as allready mentioned stages mean nowt, rob is defo the guy 2 talk 2. Over a grand 4 a set of heads i only paid 1200 quid for the whole motor! I wouldnt pay a grand 4 them.

I ask those heads and valves tvr before i order those stage 4 valves from RPI V8.
Tvr power say those stage4 valves are 43&37mm and valve stem diameter is std 8,7mm. Guides is std gast iron, (not bronze, because those valves are same material as original and original valves dont need bronze guides) but only slightly bulleted. What i understand RPI V8 bronze guides is more bulleted that tvr?
Price is almoust same, Rpi parts is slightly high-priced. But i think why? Because this valve stem diemater is 7,93mm (Racing valves) and exchaust valves are slightly bigger 38mm and guides are bronze.