Thread: Holley 390??

When are you going to add where your from ?
A 390 4 BBL is a POS , go to the wreckers and get a FalconXE/XF type 2 barrel Weber and buy an adapter ,otherwise the twin CDs on a 82 are still better than any Holley . What manifold you got that takes a 4BBL squarebore ?

Sorry I'm in brissy, so you reckon the ol stromburgs will be the best to use? What dies the 2 barrel weber go like? ATM I have a 350 Holley and it is juts certainly not big enough.
Cheers

Originally Posted by 82rangie

Sorry I'm in brissy, so you reckon the ol stromburgs will be the best to use? What dies the 2 barrel weber go like? ATM I have a 350 Holley and it is juts certainly not big enough.
Cheers

The best set-up is an Edelbrock dual plane manifold and a Rochester Quadrajet.

You can tune for more top end by cutting down the plenum divider.

What size rochester?

Originally Posted by 82rangie

What size rochester?

Quadrajet. four barrel with small primaries and enormous vacuum secondaries.

Used on Chev and Holden V8's.

The standard 2 x 175 cd will well outflow anything sub 500 CFM , albeit maybe not with an "accelerator pump" effect Then definately stick to the twin strombergs , they are the only setup that will work well offroad , but you would have to go back to the standard manifold . . (There are at least three Rochestor 4 BBL s , the one off the 253 V8 , the one off the the 308 , and a version for big blocks , all of which would be useless on a 3.5 V8 although the 253 version would probably be better than any Holley or edelbrock.)
You could always go to the Holley 500 2 barrel , with center hung floats , raised bowl breathers and a weber metereing block

So you have a 350 Holley and its not big enough ?
On a 3.5 Rover V8 ? 350 CFM at a VE 95% should easily manage 250HP ,(considering yours would be lucky to have 175 BHP) especially with a severely port-choked engine like all Rover V8's .

Your 350 , fitted with the right jets , the right power valve , and the right accelerator pump cam and diaphragm , and for sure a new set of throttle shaft seals wiill be plenty big enough for any 3.5 V8, it just wont be much good off-road at angles , Still its a Holley , works well at 2 speeds only , Flat Knacker and idle !! LOL

The only thing that will be faster with the 390 Holley on a stock 3.5 is the drop rate of the fuel gauge. You need to do the cam, valves, compression ratio, distributor upgrade and advance curve to make a 3.5 go harder. Then the 350 Holley can have a jet change maybe and will be quite adequate.

Originally Posted by 400HPONGAS

. (There are at least three Rochestor 4 BBL s , the one off the 253 V8 , the one off the the 308 , and a version for big blocks , all of which would be useless on a 3.5 V8 although the 253 version would probably be better than any Holley or edelbrock.)
LOL

The Rochester workshop manual says there are three separate models, 4M, 4MV, 4MC. The differences are in the choke operation. Basically a Quadrajet is a Quadrajet, with external differences between models mainly to do with choke, emission controls, and secondaries operation. There are minor internal differences specific to make/model and application. At full open they flow more than 3 x 2" SU's, 860 cfm. Secondary venturies can be machined out to flow quite a bit more. With the small primaries Quadrajets are tractable and efficient at low speeds and in traffic. The opening of the secondaries can be tuned to suit most engines but I would not fit one as a full four barrel to anything 3 litres or smaller, except, as I have done successfully, to a red Holden using only the primary venturis. With the Edelbrock manifold Quadrajets work very well on the little V8. I have fitted them to Rover V8's and Chrysler Hemi 265's with great success. They are effective off-road having a small central float bowl and you should use the plastic float bowl packer which was standard on the later ones. There is a section in the Rochester manual on preparation for off-road racing. Fitting one to a Rover V8 is a great improvement on the standard set-up.