What's the deal on inlet manifolds? - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

Nismo_Capri · 05-13-2004, 21:04

I have a 302 with a holley 600 vac sec, a bit of a cam specs unknown, pacemaker headers and a 3 inch 2-1..... with a factory cast 4 barrel inlet manifold. I'm sure that the inlet manifold is limiting the power at the mo'.
Apart from the weight loss of loosing this heavy POS what sort of gains does a decent inlet manifold make on these engines?
Does the factory cast manifold flow badly in the first place?

When she was on the dyno she was making 180HP and 220ft-lbs at the rears.

What manifold would you guys go for with my setup? ...It needs to be a manifold that I could weld injector bosses in to at a later date....
Thanks guys!

xacoupe · 05-14-2004, 00:42

I would not bother too much with trying to get something that works with your combo now as you obviously have bigger plans. Get all the goodies for what you want in the future and put them aside.
I can't see a std 4 barrel inlet manifold ( even a crap spreadbore one ) being too much of a drain on the 302 you have. If you want to replace it, I would reckon a 2nd hand performer would do the job with the object of selling it down the track for a more serious setup.

smciner1 · 05-14-2004, 03:19

Quote:

Originally Posted by xacoupe

I would not bother too much with trying to get something that works with your combo now as you obviously have bigger plans. Get all the goodies for what you want in the future and put them aside.
I can't see a std 4 barrel inlet manifold ( even a crap spreadbore one ) being too much of a drain on the 302 you have. If you want to replace it, I would reckon a 2nd hand performer would do the job with the object of selling it down the track for a more serious setup.

From memory the 302 Spread Bore Manifold funnels down under the Carburettor Mounting Face. The 351 Spread Bore has open holes though.

xbgs351 · 05-14-2004, 03:39

Quote:

Originally Posted by Nismo_Capri

What manifold would you guys go for with my setup? ...It needs to be a manifold that I could weld injector bosses in to at a later date....
Thanks guys!

Your going to fuel inject a 302 Panelvan?

Bounty · 05-16-2004, 03:28

got a 351 with standard inlet manifold on gas myself. same question, will a new single plain manifold make a major diffrence?

Nismo_Capri · 05-16-2004, 14:29

Quote:

Originally Posted by xbgs351

You're going to fuel inject a 302 Panelvan?

That's the plan!
The problem is that I have some rust and a paint job to pay for first.... I'm thinking the easiest way is to buy an alloy manifold and weld injector bosses to it then gut my holley 600 for a throttle body, This way I don't have to build throttle linkages. I was hoping that there was an injected clevo I could use the manifold from but no luck there.....
Here's a toyota manifold that a friend modified to fit the capri 2L with an adapter plate for me. I finished off the injector mounting bosses and a few other bits and pieces.
http://www.fordforums.com/attachment...18673&viewer=1

Nismo_Capri · 05-16-2004, 14:50

Quote:

Originally Posted by Bounty

got a 351 with standard inlet manifold on gas myself. same question, will a new single plain manifold make a major diffrence?

Good question.....what is the difference between Dual and Single plane?

I was told to get a dual plane manifold....
Cheers

Nismo_Capri · 05-16-2004, 14:53

Quote:

Originally Posted by xacoupe

I would not bother too much with trying to get something that works with your combo now as you obviously have bigger plans. Get all the goodies for what you want in the future and put them aside.
I can't see a std 4 barrel inlet manifold ( even a crap spreadbore one ) being too much of a drain on the 302 you have. If you want to replace it, I would reckon a 2nd hand performer would do the job with the object of selling it down the track for a more serious setup.

Well the problem is that an after market EFI manifold is too costly compaired to geting some injector bosses welded in to an ally manifold and running a fuel rail. This way I can get a decient manifold and run it for a bit with the carb before doing the conversion.
Cheers

xdc351 · 05-16-2004, 16:21

Redline street torquer manifold have injector bosses cast in from the factory AFAIK.

The difference between a dual and single plane manifolds is the absence of the center divider on the single plane. Dual plane manifolds are generally used on lower revving, torquey, petrol fueled engines. Single plane for high revving and/or LPG fueled engines.

Single plane manifolds start making power later in the rev range, but will keep going to 6000+, where a dual plane will usually be spent by 5500.

Nismo_Capri · 05-16-2004, 16:48

Quote:

Originally Posted by xdc351

Redline street torquer manifold have injector bosses cast in from the factory AFAIK.

The only problem I have is finding one

I can't even find somewhere selling them new on the web.... am I having a brain fart here???

I did find these awsome throttle bodies during the hunt tho http://www.redlineweber.com/Redline.htm

Quote:

The difference between a dual and single plane manifolds is the absence of the center divider on the single plane. Dual plane manifolds are generally used on lower revving, torquey, petrol fueled engines. Single plane for high revving and/or LPG fueled engines.

So I'm thinking that the dual plane is the right one for me as the engine was rebuilt by the previous owner and he said nothing about working it excpt for the holley cam and headers so I'm thinking it's a redline of 5500 at most probably 5000?
The torque starts falling off a bit under 3500 rpms and the HP is flattening off at 4500ish so I'm guessing turning at much over 5000rpms will be a waste of time.

Quote:

Single plane manifolds start making power later in the rev range, but will keep going to 6000+, where a dual plane will usually be spent by 5500.

Dual plane sounds like the plan for me....

Thanks for the help!