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Holley Carb Conversion

Postby Jeffrey Lister » 19 Dec 2017 09:16

My engine has SDi heads, RV8 exhaust manifolds, Petronix ignition and a Facet Posi Flow fuel pump, on a rolling road output at the flywheel was approx 162bhp with the SU's. I am seriously considering fitting a Holley 390 carb kit to enhance performance of the engine. Has anyone experience of this conversion and was it worth it?
Jeffrey Lister
 
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Re: Holley Carb Conversion

Postby Nic Houslip » 19 Dec 2017 11:43

Jeffrey,
I have a V8 Roadster that has an SD1 engine and was fitted with Holley Carb by the previous owner. I find that the carb is much freer breathing than the SU's and you also get a lower bonnet height. It was a bit cramped under hood, but I fitted an RV8 Bonnet [fibre glass copy from Honeybourne mouldings] so the pancake air filter fits nicely. You will need a new inlet manifold, mine has an Edelbrock. Real Steel in Uxbridge are the guys to talk to, they know the answers.
The difference between my RV8 and the Roadster is like Chalk and Cheese, the Roadster [fitted with a fast road cam] revs in a way that the RV8 doesn't. You will need a dyno run to get the carb set properly, and a dyno guy who knows the Holley, as the carb supplied will be a for "standard" Rover V8 engine [whatever that is] as yours will almost certainly need "jetting" to cope with the different manifolds and heads etc. The Dyno run will also set ignition for the best performance. Aldon Engineering in Brierley Hill [West Midlands] did mine. It will cost quite a bit as the carb and manifold will need variations in piping [coolant and fuel] electrics [ supply for autochoke] and crankcase vents, but the increase in peppiness is worth it. My email is nic@houslip.co.uk if you have any trouble with anything, I'm a technical committee member of V8 Reg
Nic Houslip
 
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Re: Holley Carb Conversion

Postby Jeffrey Lister » 20 Dec 2017 08:12

Nic,
Thanks for your response, I shall give considerable thought before making a decision.
Cheers
Jeff
Jeffrey Lister
 
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Re: Holley Carb Conversion

Postby Victor Todman » 24 Dec 2017 02:04

Jeffrey,
My roadster was converted to an SD1 engine with a Crane ' mild race' cam, rhodes lifters and a 390 Holley in 1990. The DPO left no details on the cam timing but the lifters are supposed to limit the valve lift below 3000 rpm when the full lift is restored. This set up, with block hugger manifolds, gave 168 bhp on a rolling road with a pronounced fall off in power over 4800.
I've been talking with Ian Thurkell of RPI about changing the carb to get better mpg, currently around 20. RPI are advocates of the Weber 500, saying the Holley is basically too big for the SD1 and that they can get 20 mpg from a Weber equipped Range Rover. Ian has told me there will be no drop in power from the change. He also recommended a Piper cam to replace the Crane and a return to standard lifters. These would make the engine quieter if nothing else. I'm still trying to decide if I should do this in stages, carb first or just go ahead.
In any case I think it would worth talking to RPI, they are able to fit the conversion and do any necessary re-jetting.
Cheers
Vic
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Re: Holley Carb Conversion

Postby Julian Holmes » 24 Dec 2017 11:30

Hi Jeffery,
I had my original GTV8 engine rebuilt be Peter Burgess some years ago. It had his stage 2 Econo-tune SD1 heads, K & N air filters, high compression pistons, a slightly hotter camshaft than standard, Aldon Ignitor ignition and a Facet fuel pump. It runs on the original twin SUs but, with BBC needles. The car absolutely flies and Peter Burgess didn't recommend fitting a Holley (apparently, he's not a fan, as I remember). I would recommend giving Peter a ring, he'll you give good honest advice!!! Hope this helps!
Julian
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Re: Holley Carb Conversion

Postby Chris Hunt Cooke » 28 Dec 2017 01:12

Chris Crane of RPi said to me that in his opinion the Holley over-fuelled the Rover V8 and he recommended the Edelbrock, which is just an American built version of the Weber 500, on an Offenhauser manifold, which is a low manifold for bonnet clearance. I have been very happy with that set-up.
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Re: Holley Carb Conversion

Postby Mike Howlett » 28 Dec 2017 09:31

I have heard the same comment about the Holley carb overfuelling and that the Edelbrock/Weber was better suited to a small V8. Not that I know much about these things, just what my understanding is. I do know that the SU carb is a masterpiece of design with constantly variable fuelling allowing it to operate optimally in many different conditions. A fixed jet carb is just that - fixed.
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Re: Holley Carb Conversion

Postby Jeffrey Lister » 30 Dec 2017 17:04

Thank you all for your comments. The carb has been sold so for the present I will continue with the SU's. To be honest there would have to be a decent increase in performance to warrant the cost of changing as the SU's are performing very well and I have also read that the Weber/ Edlebrock carb is better suited to our engine.
Happy New Year to all V8 owners.
Jeffrey Lister
 
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