The V8 Owners Forum -

3.5 SD1 engine
P6 10.5cr pistons with composite gaskets and SD1 heads will do about 9.75 Ill guess..

Camshaft Comp Cams extreme energy cam 270H +5'
@ .050
lift intake .481 exh .489
timing @ .050 intake open 6, close 38, exhaust open 51, close 1-
106 center line
duration @ .050, 224 intake, 230 exhaust.

Rhoads lifters.

Mangoletsi intake with quad 40 IDF's
or
Offenhauser Dual Port with Holley 390

JP. wrote: ↑Tue Apr 17, 2018 3:18 pm Mangoletsi intake with quad 40 IDF's
or
Offenhauser Dual Port with Holley 390

For me, the quad 40s by a mile, but you will need to be on your game to keep them in sync and running smoothly.

The Dual Port manifold is not all that good in my opinion, it is low rise and flows OK on a standard engine but as soon as you start to modify the engine for more gas flow it becomes the restricting factor. I also prefer non-bleed down lifters!

I'm with Sidecar - that Offenhauser has no place on a performance engine. Also, your base eninge spec is not 'wild' enough to get any real benefit from the expense and complication of Quads - you'd be better spending that money on a 4.6 short motor.

And I wouldn't be fitting Rhoades lifters either - either solids and adjustable pushrods or Cranes would be my choice.

Well Rhoads is what I like as I have several V8's running them. Its a personal choise.

Quad carbs aint complicated, the are like tripples on a V6 setup within minuts. Never had issues with multiple carbs that might be cause I am a biker runing multiple carbs daily

Problem with four carbs on an RV8 is the irregular firing order. Unless you made some fiendishly complicated cross over manifold for them. But why go for multiple carbs when injecting is cheaper and better?

DaveEFI wrote: ↑Wed Apr 18, 2018 8:47 am Problem with four carbs on an RV8 is the irregular firing order. Unless you made some fiendishly complicated cross over manifold for them. But why go for multiple carbs when injecting is cheaper and better?

Because multiple carbs look great and EFI looks crap?

But multi IDF or IDA body based EFI looks great (as good as mechanical ones) but I'd still spend my money of a capacity upgrade first.

Can't see the point on spending >£2k on induction on a 3.5L motor though . .

sidecar wrote: ↑Wed Apr 18, 2018 12:06 pm

DaveEFI wrote: ↑Wed Apr 18, 2018 8:47 am Problem with four carbs on an RV8 is the irregular firing order. Unless you made some fiendishly complicated cross over manifold for them. But why go for multiple carbs when injecting is cheaper and better?

Because multiple carbs look great and EFI looks crap?

8 throttle bodies then. For looks only, of course.

I thought that someone would mention throttle bodies! I think that Russell Ram has a point, in terms of BHP per pound spent.

Not sure how good P6 pistons are either, I think that they are weaker than the later pistons. The CR thing is no issue, you can just skim the head and/or deck in order to get the CR that you want.

Well its 3.5 and nothing more.
No bigger capacity engine there is available.

Thing is, wherever I asked, nobody has an engine for sale or is willing to ship to Holland.
I asked here on the forum, no responce
I asked the forum contributor, no responce at all
V8 tuner had nothing
and so on and so on.
RPI was the only one selling Engines to Holland.
In Holland RV8 engines are scarce. €4000 for a re-linered basic shortblock 4.0 or 4.6

So I found me a 3.5 to sit behind the Citroen tranny and there it goes.
Block + rebuild wil cost me €1500 with Cam from Compcams ( their recommendation) and all the other parts from Real Steel & Gold Card discount.
Offy intake came with the engine, Quad carb kit from eBay.

Basicaly if I understand the reponces 3.5 = crapp, Offy = crapp, quad fourties IDF are crapp but will look good in a GT40.
So its crapp what I am doing and is good for looks only. Thats a lot of negativity.

Best bang per buck is to have the heads gas flowed. Before bothering with a wilder cam or more carbs.
The 3.5 is a very sweet engine, and more sporty than a 4.6.

You asked for our thoughts!

If you are stuck with a 3.5 then fine but the fact of the matter is that people have an opinion on the stuff that you have listed and it is just unfortunate that it is not what you wanted to hear. If the Dual port was any good I'd say it was good! If the pistons are good then I would have said that they are good! I also don't like bleed down lifters, they are 'sticking plaster' for an engine that has too much cam.

The Holley 390 is probably a good carb, Edelbrocks are really my thing but I have read that there are many versions of Holley carbs, there are many versions of aftermarket parts for Holleys and it makes me wonder why this is the case, for example are the standard primary dog leg boosters any good, somebody clearly thinks that they are not and has made aftermarket annular boosters for Holley carbs. I don't think that anyone said that the quad setup was crap it's just that it is a whole lot of carb setup for an engine that does not need a huge amount of carburation, the heads just don't flow well enough so you are better off sorting them out. (having said that they are worse in terms of flow on the bigger engines).

Hi
I like the quads!
But being realistic it will be expensive and other than looks may not be the best bang for the buck.
Now a fair few GT40 cars had 3.5 and quads but ran dellorto instead of Webber and got some reasonable results.
BUT consumption was terrible like 15 to 18mpg on the road and single numbers on track days.

At 3.5 the Holley will work extremely well, be reliable and just keep going. Probably 25 to 30 mpg on a motorway run and mid teens on track day. But it does not look as pretty in the rear window of. GT40

There are numerous 8stack injection systems out there but ££££££££ and you will make more torque and probably get nearer to torque numbers that will not allow the Citroen Box to live.

Eventually the choice is yours.

Sort of like what colour will your final paint scheme be?

Ian