The V8 Owners Forum -

Ok guys, am planning my next upgrades to my 5.0 landy, which if anybody is interested is on the cover of land rover monthly this month:-) - this upgrade will involve 300 heads which I am acquiring, but which valves would you guys recommend to put in them? I run a normally aspirated / NOS setup and will probably change induction also. I though merlin valves may be a cheap option at 6 quid a valve and are a decent size? But understand they are not the best design?? What would you guys do, and apart from the obvious seats and guides what other valve train mods would be required?? (Rockers and push rods etc)

Also am thinking about pistons, flat tops are ideal for NOS with valve cut out I should imagine so I can use a high lift cam. Want compression ratio to be over ten if possible, but will I require welding to the bowls to make this? Two issues that I am keen to hear opinion on.

If you are running nitrous on this engine and its already 5 litres how much extra are you looking for??

Nitrous will give you shed loads of torque at low rpm on a stock engine. If you are thinking of a piston change I assume you are going to fit forged pistons which will be a big benefit for you on nitrous.

Flat tops with valve cut outs are ok but make sure you round off all the sharp edges of the valve cut outs to reduce the risk of detonation.

The best upgrade on a nitrous engine is big exhaust ports and valves.

How much nitrous are you using?

I'm assuming that you want low rpm torque for off road applications?

Tell us what your goal is for the engine so we can help.

The nitrous is only for occasional use, 50-100 shot at the moment but once transmission upgraded (in the pipeline) then I want to take it to Santa pod, it is more for cross country then serious off road. Enjoy green leaning, but the engine never has been a low down grungy engine, H404 cam and high rev lifters etc. I was hoping for a really good normally aspirated set up with loads of mid range 350 NHL and more in torque, topped up with gas for power runs. My stage 3 heads are great, but love to develop the set up. I know exhaust is all important in nos, as is exhaust duration. Was wondering what is practically available in terms of valves etc

This may not be directly relevant to you in the UK, but I used custom made Silchrome 21.4N valves 1.750" inlet 1.500" exhaust which were made by Competition Valves in Melbourne (which was operated by Richard Bendall who later ran Motec fuel systems).

The heads were flowed/modified by The Head Stud Co. in Melbourne to what they called "Road/Race specs".

The remainder of the parts used in assembly were:
valve stem locks - Crane 99041-1
valve stem seals - Crane 99820 -16
valve spring shim kit -Crane 99047 -1
valve springs - Crane 99893 -16
chrome moly retainers - Isky 5007ST

valve springs are 1.460 silicon chrome outer, grade 2 inner with an installed seat pressure of 130 lb. Collets are chrome hardened.

Hi
For valves I would go for swirl polished one piece stainless steel sbc ones from Manley or a similar reputable manufacturer, best bet is ebay, probably cost you about £120 to £150 for the set plus shipping and vat. With a mild low lift cam there is little point spending big money on fancy valves. I am using the above spec valves with a mechanical roller cam with 550lb/inch springs, .68" lift and a red line of about 7800 revs and I don't expect a problem. I would put a 30degree back cut on them behind the seat though Chevy valves tend to respond well to this simple mod. I am pretty sure flat top pistons and a light skim of the heads and block will get you the CR you want.
Best regards
Mike

Hi
For valves I would go for swirl polished one piece sbc ones from Manley or a similar reputable manufacturer, best bet is ebay, probably cost you about £120 to £150 for the set plus shipping and vat. With a mild low lift cam there is little point spending big money on fancy valves. I am using the above spec valves with a mechanical roller cam with 550lb/inch springs, .68" lift and a recliner of about 7800 revs and I don't expect a problem. I would put a 30degree back cut on them behind the seat though Chevy valves tend to respond well to this simple mod. I am pretty sure flat top pistons and a light skim of the heads and block will get you the CR you want.
Best regards
Mike

I like the idea of the sbc valves, but will they
Need modification in terms of height at all??? Valve guides obviously can
Be fitted as required and seas, but will abc valves be too tall or short for rover rocker gear/cams??

I think Merlin valves are longer than Rover ones. There are good cataloques from valve manufacturers, google Manley and download. They contain dimension so you can choose from there.

http://www.british-cars.org/mgb-gt-v8-t ... 923513.htm


Above is a link to a site where you can find some details about valve options.

DaviesDJ wrote:I like the idea of the sbc valves, but will they
Need modification in terms of height at all??? Valve guides obviously can
Be fitted as required and seas, but will abc valves be too tall or short for rover rocker gear/cams??

The Buick valves will have come out of one sbc parts bin or another both GM engines. Get a chevy valve, when I get home from holiday I can send you a couple, put them in the heads with some checker springs and measure them up. . . Decide what works and buy them. You get a wide range of lengths of chevy valves because of all the different factory and after market heads.
Best regards
Mike

I believe the ones suggested are F6237 and F6238 made by Ferrea

http://www.race-mart.com/Ferrea_Racing_ ... 237-1.html
http://forum.britishv8.org/read.php?6,12170

What do recon Mike?

Hi Reg
I recon they look like very nice valves, they are higher spec than the ones in my chevy but not silly money they are waisted stem as well which the rover head likes and as it seems to be used on the v6 Buick I suspect it would be a good idea on the 300 remember the 300 and the v6 were derived from the 215 at about the same time, actually about the same time the sd1 was developed from the 215/p6 the same thinking will have gone into all three. I also have a feeling that these sizes are very close to sbc vortex truck head valve sizes. When I get home I'll measure up the various valves I have and see how they compare to Buick 215, 300, and v6. Atleast when that is done sorting out the rocker geometry should be a heap simpler than mine!
Best regards
Mike

Thanks guys, many options to look at! In general I know thatthe limits are 1.77 and 1.5 inch. And if your in for a penny your in for a pound so will look to fit the largest after the seats are installe, wont, pop them in either untill a spot of welding up is donw. In general what is your favourite shape of valve for the 300s in terms of stem etc??? And were best should bowls be welded to increase comp ratio - or is it better for combuistion and squish to keep the chambers standard and just put a higher comp ppiston in??? Really hope to take the landy to the strip with the current set up prior to this next cook up (this is next years rebuild om the pipeline) - hopefully may bump into a few of you guys there

We welded them around behind the spark plug apertures - brought the volume down from 54 cc to 37 cc, then fitted 300 steel shim head gaskets. Didn't appear to adversely affect flow or swirl in the combustion chamber.

One problem you may encounter is that the Rover inlet manifold ports don't reach up high enough to mate with the much larger 300 ports. Only the original and very rare Hufaker manifolds addressed this problem - they were made by Hufaker Engineering in the US specifically for BL around 1979/80 for use on the TR8 works rally cars, and they did match the 300 inlet ports perfectly (which by implication suggests the works TR8s were fitted with Buick 300 heads). The SU, Edlebrock Performer and the efi manifolds don't extend high enough resulting in a port mismatch. Wilpower manifolds are slightly better.

Solution is to weld the manifold flanges and recut them to match the ports in the heads, then open up the Rover inlet gaskets if they'll reach up far enough, or fit Buick 300 or P76 maniold gaskets which are taller (but the Buick is a 3 piece affair).

Here's another interesting link

http://www.leylandp76.com/technical/tech-headflow.html

Am going to use a custom crossover manifold and modify that, yes have been prepared for that niggle:-), whe did you source you CHG and inlet gasket from??