F85 Cylinder Heads - edelbrock manifold - match the parts?

DaviesDJ · Post by **DaviesDJ** » Tue Jun 26, 2012 5:26 pm

Hi guys:-) firstly don't mind saying that I'm a bit addicted to the forum, found everybody so helpful, and keeps my wife's eyes rolling. Anyway a while ago I put my name down with Charles at real steel for the merlyn f85 hEads when he gets round to casting them. But was thinking - will I be wasting my
Money?? I'm running a performer manifold and Eddie 600 with a 5.0 rover, surely the manifold will be the restrictive point?? I was told that switching my current stage 3 big valve rover heads (not ultra big valve) would give better performance mid and top end and all round more wmmph and grunt, but this manifold would have to go??? And that's another cost! What do you guys reckon? Are stage 3 heads the bottle neck I am told???

kokkolanpoika · Post by **kokkolanpoika** » Wed Jun 27, 2012 9:55 am

I´m building 4.6litre engine to my friend. 11.2Cr ratio crower 50232Cam, MS3X fuel injection with wasted spark..

We order set of STD Merlin heads to John Eales.. When i look those heads Exhaust port floor is slightly better looking than rover heads. And if you made some porting work, hole port will look better then.. not sure for flow bench readings when ported.. with ported rover vs STD F85 rover will outflow merlins approx 20-30cfm
Inlet port is also ok, if you accept that valveseat is smaller than inlet port, approx +1-2mm strangle one side, not good for high performance.. Also valve design is bad.. It will need new valves before it will perform better.. 8.7mm valve steam diameter is bad also design for valve saucer is bad.. And they are heavy valves.. Made by Dell West witch is good..

If you want to make power buy set of stage 4 heads or raw casting for merlins.. I will estimate if i buy set of raw casting F85 heads, without valves, seats and valve guides etc.. Fit 8mm valve steam, better designed valves, new approx 1-2mm offset bronze guides at inlet side.. it will flow mutch better... +400hp for 5.0litre

John Eales has got ported set of Merlins.. I think 1500£?? Call him if intrested.. Or buy his CNC heads same price..

DaviesDJ · Post by **DaviesDJ** » Wed Jun 27, 2012 4:24 pm

Thanks mate, I know that heavily ported standard heads flow better, but the merlin heads represent a better starting point, I suppose what I was wondering was if you were running an edelbrock manifold would this be too restrictive for either?? I mean - is the bottle neck the inlet manifold?? And do these heads represent a gain throughout the rev range or just at top end???

DaviesDJ · Post by **DaviesDJ** » Wed Jun 27, 2012 6:23 pm

Yes, have thought about EFI, but at first i felt comfortable with a carb, and thought that a well done carb is easier to maintain and tune, with minimal loss of power, the carb itself is good for 400hp i think, its the manifold as you say, so if I ever did get the merlins i would have to change the manifold - anybody got any thoughts on the best 4 barrel manifold for fast road use? With those sorts of 'stage 5' heads??

But then part of me says sod it all and spend the money on NOS setup or turbo kit!

kokkolanpoika · Post by **kokkolanpoika** » Wed Jun 27, 2012 7:10 pm

You can found topick of merlin heads if you use forum search..
MinorV8 has got some dyno results of merlin heads VS standard.. I think he run first edelbrock and it will give 11hp more than home ported rover heads and then he fit single plane and it is worth extra 25hp on ported rover heads???
I understand that edelbrock manifold is quite resistive say over +280hp
Why dont you go for EFI/megasquirt? 45mm trumpet base/manifold?

Darkspeed · Post by **Darkspeed** » Wed Jun 27, 2012 10:27 pm

Best 4 barrel manifold is the Harcourt / Wildcat Spider medium rise if you have room for the height.

JP. · Post by **JP.** » Thu Jun 28, 2012 3:40 pm

Merlin Heads are rubbish.
They only gave me 40bhp increase straight out of the box over my bone stock heads on my forced induction 3.5.............
At that time ( first batch ) they where only a 1000 quit for a fully assembled set which was ( and still is overhere in Holland ) cheaper then rebuilding & converting my bone stock heads to more race spec.

Everything Charles ( RIP) told me & promised me came out and was true.
For me it was the best value for money.

Yeah I want more horsepower now and best value for money also so plans are to skip the RV8 in favour of a Viper V10 in our Capri. Cant tune a RV8 to that level which a Viper V10 has stock untuned...for that less of money.
Viper V10's only need a pair of turbo's to get realy insane....

What I want to say....
If Charles told you so.......... he told you the right thing.
Most people running Merlin heads are not on this forum so experience & knowledge on this is not here, only assumptions..
Merlin heads are scarce and are rarely up for sale while all batches are sold out each time. So people must like them........

DaviesDJ · Post by **DaviesDJ** » Thu Jun 28, 2012 6:48 pm

Thanks JP, take it you like them then:-) Buy the way - what configuration and how did you force feed your rover - am giving serious thought to turbo (hence poll question) thinking I could fabricate two manifolds - 2x T3's, blow through an intercooler then blow through my edelbrock carb! Is it more complicated then this?? Or is that all there is to it? (obviously cooling - oil feed to turbo and jetting carb)

Robrover · Post by **Robrover** » Sun Jul 01, 2012 9:24 am

Huffaker or Willpower manifolds with Buick heads will deliver the goods.

Lanocha Racing in the US has flowed over 200cfm from Buick 300 aluminium heads which was sufficient to support 425 hp on a maximum-effort, high-compression, normally aspirated 5.0 litre TR8, and that’s using a single-four-barrel Daemon Racing carb on a Willpower open plenum inlet manifold, not efi.

The V8 Owners Forum -

F85 Cylinder Heads - edelbrock manifold - match the parts?

High end normal asp rover or quick and dirty turbo conversion to stock land rover 3.5

F85 Cylinder Heads - edelbrock manifold - match the parts?