The V8 Owners Forum -

I run a pair of well worked/flowed alloy 300 heads on my 4.6, fitted with 1.75/1.5 valves.

They were developed by The Head Stud in Melbourne and were originally fitted to a long stroke 4.4 P76 which has the same bore as a 3.5 Rover. They will support up to 405 hp according to the flow calcs.

To get the comp ratio up for the deeper dished 4.6 pistons I welded up the combustion chambers to reduce them to 37cc, shaved 080in off the faces and used Buick 300 tin gaskets.

Thanks Rob.

Useful information.

With my pistons which are Keith Black flat tops with 5cc. valve reliefs (Chevy 305) I took 40 thou. off each the heads and decks and with comp gaskets achieved approx 9.4/1 static CR and with the Crower 50232 cam thise gives a dynamic CR of approx 8.8/1 which is reasonable.

Kevin.

Robrover wrote:
They were developed by The Head Stud in Melbourne and were originally fitted to a long stroke 4.4 P76 which has the same bore as a 3.5 Rover. They will support up to 405 hp according to the flow calcs.

Rob,

Your valves have been moved nearer to centerline ?

Dimitri,

The 1.775 and 1.5 valves seem to be what Dan Jones fits in his 300 heads without moving anything.

Did you see my post the other day re a load of stuff Dan bought which included a pair of specially cast hybrid 215/300 heads.

http://www.v8forum.co.uk/forum/viewtopic.php?t=5733

Makes interesting reading.

Kevin.

It is just I am curious to know how they did to instal so large valves in 3.5" bore without moving them nearer to centerline. As one time you try to instal Buick head on 3.5" bore block... inlet valve touches the liner.

Yes I seen Dan topic.... I am jealous .

http://www.bacomatic.org/gallery2/v/hid ... s.JPG.html

http://www.bacomatic.org/gallery2/v/hid ... s.JPG.html

But for me the dream would have been that : Buick 300 ports, Buick 215 chamber and Olds 215 valves position

Dimitri,

Yes a mouthwatering load of goodies, I hadn't seen the pictures and that 2 x 4 Barrel inlet looks very nice as well.

Whats the difference in the Olds 215 chamber layout?

Kevin.

Here an pic of Olds chamber from :
http://www.britishv8.org/Articles/Strok ... e215V8.htm



Valves are nearer to centerline but same if 4 barrels uses 38cc chamber instead 51cc for 2 barrels, the position of spark plug is more eccentric compared to Buick/Rover head.

Dimitri,

Good article on the Olds 215 heads, hadn't seen that before, looks like they would work well on the smaller versions of the Rover with only the port runner size being too restrictive on the larger engines, although it looks like there is scope for bigger valves if required.

The article is a little confusing as it quotes two different sets of valve sizes and not sure which is shown in the main picture and what was used for the flow tests, from the layout of the combustion chamber the Olds version would seem to offfer a greater squish area.

From memory isn't the rocker system and oiling different to the Rover Buick heads?

Kevin.

Those Mickey Thompson hybrid heads that were specially cast by GM sound fascinating. I guess I was trying to do something similar, by a far cruder means, by reducing the size of the 300 combustion chambers down to SD1 cc.

What a find though, all those early '60s BOP parts.

Wotland - I think on reflection the P76 may have been bored to take Holden 186 pistons, although I can't recall precisely as it was mid '80s. A lot of those engines found their way into Rangies around that time and 300 heads were the ones to get from the US.

As you may know most Aussie speed shops do regular shopping trips to the US and bring back containers full of new and used of GM, Ford, Chrysler stuff, so it was just a matter of putting in an order here, wait a couple of months and they'd track down what you wanted and supply it.

My heads came from a wrecked Buick 300 languishing in a breakers yard in the Arizona desert.

Kevin,

On Olds heads it seems oil is supplied by one end of shaft and not by external rocker shaft pedestals like RV8/Buick.

Rocker ratio is the same with 1.58:1 but rocker arms are different and are in steel with the rocker shaft pillar bolts going right through the head into the block (the "sixth bolt").

Dimitri,

The olds heads sound like they have potential but haven't heard of many people using them.

Kevin.

I'm pretty sure the BL Works P6B Rovers used Olds heads in the 4.3 engines that TRACO Engineering built for them.