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Please consider these pages where created 10 years ago and are for Historic Information Purposes Only. For current stock, prices and information please visit our V8 Engine and Component listings in our eBay shop.


Heads, Unleaded and High performance

Unleaded and Performance Heads
Additional information for Early P5 and P6 Engine
Unleaded Cylinder Head Inc. std, Stage 1 & 3 Plus New Ultimate Big Valve. Pre - 76 to present date.
Improvements to flow rate & efficiency achieved by RPi unleaded Heads
Unleaded and Performance Heads

With increasing speculation on the demise of 4 star fuel, RPi can ensure your engine is 'Millennium Proof' because all of our engines now include unleaded heads as standard, or we can supply them for your engine. (a surcharge may apply to all heads)

As you will see, our extensive list of replacement heads ensures there is a pair suitable for your engine and engine requirement regardless of age or type of your V8.


Notes on Heads.

(A surcharge applies (per pair) if, for whatever reason, exchange/return heads are not available.

Our latest 10 or 14 bolt fixing, unleaded, oil impregnated guides, and fully-enclosed guide seal inlet and exhaust, and are compatible for all V8s from 1960 through 2003.


Head rebuilt Kit, (unleaded) œPOA
Recon. heads chemically cleaned, faced, new valves, unleaded guides. (pair) See web pages for full Specification œPOA
Stage 1 reconditioned heads (pair) See web pages for full Specification œPOA
Stage 3 (fast road, high torque ) recon. heads (pair) all performance heads are individually hand finished (pair) See web pages for full Specification œPOA
Ultimate big valve heads, For 4.8 to 5.2 capacity or serious competition.

We have used them on engines up to 334 bhp, we have seen them tested on engines up to 400bhp, indeed my own 5.2 with these heads can produce over 403 FT/LB torque at 2800rpm but I must confess we don't have the flow data to prove it. (I guess we spent too much time porting) But quite simply we believe they are the best you can do, without starting again with a new solid block of Aluminium.
œPOA
Head Gasket set, available with composite or shim steel, also composite option for Valley gasket. œPOA
Head bolt set (latest stretch type for improved sealing) all 20 in set. œPOA
Head Stud Kit. (for higher performance use) inc. high tensile washer set. œPOA
Head bolt set std. type all 28 in set. inc. head washer set, high tensile strength œPOA
Valve spring set for standard and performance cam applications. œPOA
Standard inlet/exhaust valves œPOA
Big (Stage 3 valves) for use with std. valve seats (need machining)
Inlet Std. ( 39.83 mm ) Big. ( 41.46 mm )
Exhaust Std. ( 34.42 mm ) Big. ( 35.54 mm )
œPOA
Valve guide set, unleaded, with new style seals. œPOA
Rocker shafts - each œPOA
Genuine Rocker arms - each, (16 required) œPOA
Push rod set œPOA
Push rod set - adjustable œPOA
Shim Kit essential for all tappet pre-load settings. œPOA


All prices are per pair & include valves and valve springs. A surcharge may apply if no exchange heads are available.

If you wish to retain high compression, or increase compression (this would not normally be of great importance) and use composite gaskets, it is not possible to remove (skim) enough from the face of the heads. So the solution would be to re-face the engine block or use the latest 4.0 & 4.6. Rover heads which have only 28cc combustion chamber.


Additional information for Early P5 and P6 Engine

(Fitted also to early Morgan, Marcos, MG, Land Rover & Range Rover)

We have been contacted in the last few months from many clubs and customers worried about the reduction of fuel quality and necessity to run unleaded. It is now possible to offer a solution to solve the problem for V8s including all those high compression early (pre-'76) engines.

Rebuilt early heads with enlarged new valves and valve seats to standard later specification ensuring no loss of power but running unleaded fuels. Unleaded valve guides and later valve stem neoprene seals. Fully chemically-cleaned and re-faced, and finished with valve springs.

This will solve 2 of the 3 problems associated with unleaded fuel, the third problem is caused by the high compression and this can easily be reduced by the use of composite head gaskets. They will prove a far more effective seal than the standard shim steel gaskets and lower the compression to an acceptable 9.8-1 (variable from engine to engine) no loss of power will be resultant due to the more efficient valve sizes furthermore originality is not impaired apart from the fact the Dual springs will be replaced with less damaging single springs (Dual springs not required on our heads unless your engine is going or expected to rev beyond 6500rpm)

Please note ------ The reason the compression has to be lowered is that it would be almost impossible to avoid 'Pinking' (pre-ignition) on a 10.5-1 compression ratio.



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RPi - Unleaded Cylinder Head Specifications

Reconditioned unleaded standard.
New valves and unleaded valve guides, fully enclosed 1996 specification valve stem seals, preceding this the heads are skimmed to ensure accurate facing to the block, acid dipped complete the finish (you could safely eat you tea off them) fully assembled and combustion chambers are CC'd.

Optimal Efficiency' without going over the top.

Stage 1 Reconditioned.
Cleaned and refaced as per Standard reconditioned above, with the addition of gas-flowed inlet and exhaust ports and throats, modified and improved combustion chambers to ensure correct flow to the accurately machined three compound angle Valve seats. And with streamlined valve guides, new valves and valve springs, add up to make our STAGE 1 heads the best value around for affordable power gains and increased efficiency (much more of what you need best 'Street and High Torque' efficiency).

Same exchange issues as above.

Recommended but not essential for fast road, larger capacity road and/or smaller capacity semi-race engines, especially if you want to Optimize your engines performance and economy.

Stage 3 Reconditioned.
For all those V8 owners and drivers seeking near maximum potential whilst retaining affordability, competition specifications and street driveability, these heads are for you. STAGE 3 achieves, as you would expect all the highly detailed work or our acclaimed STAGE 1 heads, but further utilize the largest size valves possible and compatible to standard valve seats, they are supplied fully ported and engineered to precisely match gasket facings and substantially enhance flow rate and are supplied with Hi-rev Valve springs to match your camshaft choice (check out the massive bhp and relentless torque of our Stage 3, 4.6 V8s that regularly use these heads).

Optimum Street and clubman race power without losing sight of low-end torque and efficiency, making the torque and bhp band seem endless, and working to make the V8 what makes it all the Buzz on the street or Off-road.


links to other component pages
[ Back to: V8 engine and component information and pricing ] [ Carburetion & fuel Injection ] [ Electrical ]
[ Transmission 2wd & 4wd ] [ Suspension, Handling, Tyres, Wheels & Brakes ] [ Stainless & Mildsteel Exhaust systems ]


Prices do not include local EU.Tax.(VAT).
Prices & stock are subject to change without notice. Information and advice, as always, is free.

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