Engine and Transmission Tech

Anyone out there, running this combo ? Not the sidedrafts into a 4bbl manifold. Similar to the Offy 2x2 manifold.I like the equal runner lengths and distribution. Problem with the BOR., single plane 4bbl manifold, is 4 short and 4 longer runners.Thanks, roverman.

If not the Offy twin 2 bbl setup what manifold are you referring to? Custom? I've seen some Rover manifolds modded to take a single 38/38 Weber but nothing using two downdrafts.

Dave, were the Offy about 2" taller on runner feed in, I would mod. for Holley 2300's. (2) racing carbs around $1,100. All considered, not so hot. I have much to do prior to manifold selection. I could make one out of fiberglass, and run it like Huffaker did. I've been told Webber IDF's/etc., woun't work on plenum manifolds."If" I find my Huffaker single plane, I''ll probably start with POWERJECTION TBI. Cheers, roverman.



Edited 1 time(s). Last edit at 12/23/2010 05:11PM by roverman.

Art,

I was researching a project earlier this year which needed to use standard carbs for a 215 V8 and cam up with a company that modifies and supplies 2 barrel, I think Rochester carbs that will flow impressive amounts of air/fuel mixture,from memory I think it was well over 300CFM per carb.

If thats of interest I will try and find the data for you.

Kevin.

Kevin, I will need close to 900 cfm. Making a suitable (2) 2bbl manifold, probably a bad idea. I'm leanin "POWERJECTION TBI". Thanks, roverman.



Edited 1 time(s). Last edit at 12/23/2010 05:12PM by roverman.

Actually, the Rochester 2G used on 400 Pontiac and Olds flowed 400 CFM stock. Nice if you can find them. I don't remember the aftermarket companies name that Kevin referred to but, I remember their ad. Another carb option would be Pony carbs Autolite, in my opinion better than the Holley 2 barrel. You can buy the twin 2 barrel manifold from Offenhauser. I think you have a good idea there Roverman. One on Ebay right now for $325. [cgi.ebay.com]



Edited 1 time(s). Last edit at 12/21/2010 11:30AM by mgb260.

Art,

Check out your local marine shop.
Mercruiser, etc. used a monster 2G carb on lots of marine engines. Used to race them on our "stock" Malibu. Most won't have a power valve but everything is there to add one.
You could use two TBI throttle bodies (454 truck) and an aftermaket ecu on that manifold that Jim found.
Not too thrilled about the projection unless its changed some. Used one years ago and wasn't very happy with it.
It's an Alpha N setup with too little adjustability.

Cheers
Fred

> Dave, were the Offy about 2" taller on runner feed in, I would mod.

Edelbrock also made a 2 x 2 bbl intake. The Edelbrock was a dual plane
(the Offy is more of a plenum with very short runners). If you cut the
plenum dividers down on the Edelbrock, you'd end up with something that
tunes like a longer runner single plane. I sold one a while back and
have the dimensional data in my database. IIRC, it had ports that were
slightly larger than the Edelbrock Performer Rover dual plane.

> If I find my Huffaker single plane, I''ll probably start with Projection
> TBI.

Art, the Huffaker has Buick 300 intake ports which may not be a good port
match to your cylinder heads. Is your intention to open up the Merlin
heads to match the Huffaker?

> Actually, the Rochester 2G used on 400 Pontiac and Olds flowed 400 CFM
> stock.

Remember, the pressure drop 2 barrel carbs are rated at are not the same
as 4 barrel carbs so 400 CFM from a 2 barrel carb is not the same as 400
CFM from a 4 barrel.

> I remember their ad. Another carb option would be Pony carbs Autolite,
> in my opinion better than the Holley 2 barrel.

I wouldn't get a race carb from Pony Carbs. A much better source would
be Bobby Oliver at Competition Carb in Nevada. The Autolite use annular
boosters and the Holley 4010/4011 series carbs were basically a redesign
of the Autolite 4100 carbs. You can use the Holley booster clusters in
the Autolite 2 barrel carbs. Bobby did a carb like that for a friend of
mine's circle track engine.

> Not too thrilled about the projection unless its changed some. Used
> one years ago and wasn't very happy with it.

Holley's Projection has changed several times over the years.

> It's an Alpha N setup with too little adjustability.

For Art's racing application, Alpha-N is all he really needs (or wants).

Dan Jones

I speak of "POWERJECTION II or III", by Proffessional Products.They allude to refinement over the years. I shall compare intake port sizes of Huffaker ported heads to the Merlins. Were someone to provide a better designed 4bbl,(drawing), for the Rover, I would probably "glass one up". Thanks, roverman.



Edited 1 time(s). Last edit at 12/23/2010 05:13PM by roverman.

Hey Art,

Projection is a Holley part.
Powerjection is the one that you are considering.
The powerjection is a speed density system which may not be easily tuned if you are running a big cam.
Dan is absolutely right that an Alpha-N system is all you need if your only going to mash the throttle.
But I still think the Holley system doesn't have enough tuning latitude.
It's way too easy to under fuel the engine on the top end. And the Holley ecu can't keep up with the airflow demands.
The fix is to use the Commander 950 ecu, which is speed density, but by the time you've done that why not just port inject it properly?
Are you running a "Faux barrel" for a reason?

Cheers
Fred

> I shall compare intake port sizes of Huffaker ported heads to the Merlins.

I measure the Huffaker intake manifold ports at 1" by 1.75", a perfect
match for the aluminum Buick 300 heads and GM 215 race heads. I don't
think you can port to a Buick 215 or standard Rover head out that far.
The Edelbrock 2x2 barrel ports were 0.9375" x 1.625" and an Edelbrock
Performer Rover are 0.895" x 1.5625".

Dan Jones

Was there ever a 2x4 barrel intake for 215 engines ? I think i have seen some pics somewhere but could not find them on my computer... could be wrong though.

Dan, have you ever flow tested a Eddy Performer Rover intake, how much hp could that intake provide ?

Fred, Powerjection-got it. I knew it started with a "P". Faux 4bbl for "vintage" build look.Now if I could find the Leyland,"works", x-ram-port injection set-up, Sweet ! Dan and clan, Since intake port of Merlin is 1.8x1.02, that Huffaker 4bbl, should port to match. Cheers, roverman.

> Was there ever a 2x4 barrel intake for 215 engines?

Yes. GM cast a small number of 2x4 barrel dual plane intakes.
I have one with a two Carter 400 CFM AFB's.

> I think i have seen some pics somewhere but could not find
> them on my computer...

I think there are some pictures of mine at:

[www.bacomatic.org]

I don't know what I'll do with it as it doesn't fit under the sloping hoodline
of my TR8.

> Dan, have you ever flow tested a Eddy Performer Rover intake, how much hp could
> that intake provide ?

We only flow tested the single plane intakes. Previous dyno testing
on cylinder head limited engines had shown single plane intakes to be
better across a wide RPM range for larger displacements (relative to
head flow). Plans are to dyno test a 4.2L Rover over the winter.
That might be an opportunity to test the dual planes.

> Dan and clan, Since intake port of Merlin is 1.8x1.02, that Huffaker
> 4bbl, should port to match.

Good to know.

Thanks,
Dan Jones

I shall measure and post port dimensions of Offy 2/2bbl intake,(very close to 215 std. size), and ported Huffaker intake. 2/2 Offy is actually a couple $'s less than their 4 bbl. Both are about lowest height available. roverman.

Art, Did you get that manifold on EBay or new from Offy? I think you will see better fuel distribution. What carbs or are you planning TBI?



Edited 1 time(s). Last edit at 12/23/2010 11:39PM by mgb260.

I just remembered the mid 80's 3.8 Ford V6 and 5.0 V8 had TBI with Ford/Holley 2 barrel base pattern. You could get 2 from the junkyard and use stock ECU or aftermarket controller and harness. Might work pretty good. You would need Rochester to Holley adapters too as the manifold has Rochester pattern. Port match adapters with TBI and manifold. Use the 5.0 injectors in the throttle bodies. Use the high pressure pump from the 3.8 or 5.0 with return line also. Here's a picture of the TBI:




Edited 2 time(s). Last edit at 12/24/2010 02:09AM by mgb260.

Jim and clan, IMHO the Offy 2/2bbl should be fine for street work, but worthless for racing. Runners are way too low and short.I buy direct from Offy. Jim, you didn't mention flow of the ford/holley, at 3" hg. ? My first choice is a "vintage" look. Cheers, roverman.

I don't know about flow but,venturi and butterflies and gaskets look about same as 500 Holley 2 barrel.Also it uses standard 5 1/8" air cleaner size. You could use a homemade drop base with 2" K&N filter. Probably 6-7" diameter. Or dual quad large oval.



Edited 3 time(s). Last edit at 12/24/2010 03:16PM by mgb260.

Here is a good example of a dual TBI: