The V8 Owners Forum -

This has probably been asked many times, but what exactly is wrong with the RV8. I mean a good 4.8 is making 280BHP (WITH stage 3 heads), when a Ford 5.0 is making 345BHP. Are the heads on the rover really THAT bad?? And we cant argue that its because the Ford is 200cc bigger because when we increase the RV8 to 5.0, it makes next to no difference....

People go on about the cost of tuning a Rover, and while thats true if you try to emulate larger yank V8s, seems to me a decent 3.5 or 3.9 can make an honest 200-220+bhp very cheaply indeed. And a std smog Ford or Chevy might make only 140 or 175, if more torque though.

But the cost of building a 4.8 vs buying a 302/5.0 probably isn't so good a comparison. And the Ford has the potential to make what 400bhp without major surgery.

'the heads on the rover really THAT bad??'

I think the easy answer to that is yes, they they are. If you replace them with a set of Wildcats, for instance, then your 4.8/5.0 will make 350-450HP without much difficulty at all.

Starting from a set of heads, designed (in the late 50's/early 60's) to work on a 3.5L motor, then modifying them and sticking them aon a 5.0 motor and comparing them to to modern aftermarket performance orientated units on a SBF/SBC is not really fair. A bit like comparing a stock 60's 40HP Kent engine to a tuned Zetec perhaps?

Just compare the ports and valve sizes on a decent set of SBF/SBC heads to those of the factory RV8 units and you have most of the answer.

Russ

russell_ram wrote:'the heads on the rover really THAT bad??'

I think the easy answer to that is yes, they they are. If you replace them with a set of Wildcats, for instance, then your 4.8/5.0 will make 350-450HP without much difficulty at all.

Starting from a set of heads, designed (in the late 50's/early 60's) to work on a 3.5L motor, then modifying them and sticking them aon a 5.0 motor and comparing them to to modern aftermarket performance orientated units on a SBF/SBC is not really fair. A bit like comparing a stock 60's 40HP Kent engine to a tuned Zetec perhaps?

Just compare the ports and valve sizes on a decent set of SBF/SBC heads to those of the factory RV8 units and you have most of the answer.

Russ

Hi Russ,

In alot of books that I've read on tunning the RV8 lump they reckon that they're no bad "standard" rovers heads, SD1 are only slightly better than the earlier ones. What the books should really say is that they're all AS BAD AS EACH OTHER!

Cheers,

Pete

Basically what Russell says. All the rover heads were basically made for a 3.5 engine and very little has changed to them over the years. Here is a question for you. Would you try and build a 347 stroker out of a 302 without buying new heads for it? I think the honest answer to that is of course you wouldn't so why would you expect to be able to add 1.5 litre and 200 bhp to a rover without doing the same? Course the trouble is aftermarket rover heads are much more expensive than the American offerings, that said if people spent money and bought them they would come down in price.

I think one of the problems with the rover heads is the valves do not sit on the centre line of the bore, thus restricting the size of vave you can get in there and as you get bigger the valve starts to be shrouded by the bore, if you ever see a pair of Vizard heads he has slotted the head bolt holes to move them to the centre of the bore, the next thing with the heads when you get to bigger valves is the exhaust port, it hooks back above the valve, and it really is quite hard to get a good gas flow around the bend and a large enough area to get enough gas flow,, it can be done, and I am experimenting with a few Ideas to get around this, but it does entail a lot of machine & Porting work if it works the need for welding may be negated as well,
The X bolt heads are meant to be the best stock heads from rover, and the Heads from Real Steel are meant to be good too.

ian.stewart wrote:and the Heads from Real Steel are meant to be good too.

Has anybody tried them yet?

Chris.

ChrisJC wrote:

ian.stewart wrote:and the Heads from Real Steel are meant to be good too.

Has anybody tried them yet?

Chris.

Yess and now I know for shure, stock heads even staged heads are not worth a penny compared to this stuff.

My 50 cents : Wildcat or Merlin F85 heads are the only ones to go for on a performance RV8.
Its not worth the money to invest to stage your own heads to whatever level compared to this stuff.

But back on topic, a stock 302 Ford two barrel engine delivers the same horsepower as a stock 215 RV8 with twin Su's.
The Ford Motorsport 302 has 345 ponies with GT40 spec heads....
On a 4.8 RV8 you can expect about the same with a decent set of heads.. but this engine is lighter meaning better handling and better acceleration.

Costwise, probably better to buy a Chevy LS-? instead of both..
But as always; somebody will go faster,so Id stick to my 3.5 blown'd/ Merlin'd RV8.

JP. wrote:My 50 cents : Wildcat or Merlin F85 heads are the only ones to go for on a performance RV8.

But as always; somebody will go faster,so Id stick to my 3.5 blown'd/ Merlin'd RV8.

I'd agree about the Wildcats - my engine is soon to be completed with them.

But what are the Merlins? I've never heard of those!

5000SE wrote: But what are the Merlins? I've never heard of those!

They are a new casting developed by Real Steel

katanaman wrote:

5000SE wrote: But what are the Merlins? I've never heard of those!

They are a new casting developed by Real Steel

Really - anybody know how they compare back-to-back with Wildcats in performance - or price?

http://www.realsteel.co.uk/section1.pdf page 6, they are £1100 a pair. Comparison I have no idea, I would say the wildcats ultimately will be better but beware there are different version of wildcat heads so comparisons might not be fair between them.

katanaman wrote:http://www.realsteel.co.uk/section1.pdf page 6, they are £1100 a pair. Comparison I have no idea, I would say the wildcats ultimately will be better but beware there are different version of wildcat heads so comparisons might not be fair between them.

Well, that's bloody cheap for what they are compared to most people's Stage 3 and 4 heads. I've not seen the Merlins yet, but guess they're a step or two down from the Wildcat league:

Most stage 3 typical 1.63"/1.42" £7-1100
Stage 4 typical 1.69"/1.45" £1500-2000
Merlins 1.73"/1.45” £1100.
Wildcat Stage 1 1.85"/1.55" £2000 (incl roller rockers)
Wildcat Stage 2 1.95"/1.6" £2500 (incl roller rockers)

I have Stage 1 Wildcats - the 2s are race-only - ports just too big to generate smooth gas velocity on the road.

At those prices Real Steel should be putting every other modified head supplier out of business. That said, they quote making 343lbft out of a 5.0 with these heads - I've had 367lbft from a 4.6 that V8Dev built me with their Stage 3 heads, so more resuls would be interesting . . .

5000SE wrote:

katanaman wrote:http://www.realsteel.co.uk/section1.pdf page 6, they are £1100 a pair. Comparison I have no idea, I would say the wildcats ultimately will be better but beware there are different version of wildcat heads so comparisons might not be fair between them.

Well, that's bloody cheap for what they are compared to most people's Stage 3 and 4 heads. I've not seen the Merlins yet, but guess they're a step or two down from the Wildcat league:

Most stage 3 typical 1.63"/1.42" £7-1100
Stage 4 typical 1.69"/1.45" £1500-2000
Merlins 1.73"/1.45” £1100.
Wildcat Stage 1 1.85"/1.55" £2000 (incl roller rockers)
Wildcat Stage 2 1.95"/1.6" £2500 (incl roller rockers)

I have Stage 1 Wildcats - the 2s are race-only - ports just too big to generate smooth gas velocity on the road.

At those prices Real Steel should be putting every other modified head supplier out of business. That said, they quote making 343lbft out of a 5.0 with these heads - I've had 367lbft from a 4.6 that V8Dev built me with their Stage 3 heads, so more resuls would be interesting . . .

I agree with that... More resuls would be interesting with Merlins.. Speeches are "hard" but ever seen a dyno graph with those heads in "civilisation" only some graphs with the seller/computer..

I would be interested to see how a set of the new Merlin's compare to a set of "worked" Buick 300 heads. I know they don't compare to the Wildcats, but, cost being a factor, I'm curious about the Merlin's.

Greg