: Intake manifold for the 425

09-28-04, 11:49 PM
I was interested in getting an intake manifold for the 425 4-bbl. I was just on the jegs website and I know they have them for the 472 and 500cu. in. engines(edelbrock) but it doesnt say anything about the 1977+ engines. Will it fit or does it need to be machined? Is there another manufacturer of high performance intake manifold who has made one for the 425? Thanks for any suggestions!

09-29-04, 02:37 AM
The Edelbrock Performer 472/500 intake WILL fit the 425. And it's pretty much the only non-stock intake choice for the 425, seeing as the Bulldog and Boogieman are way too big for even most 500s. You can also try your hand at porting the intake you have if you feel like researching that and trying it.

10-01-04, 01:33 AM
I just emailed the techs at edelbrock that same question I'll post their reply if they answer

10-01-04, 03:38 PM
they replied and said it wouldn't fit "This intake does not fit your application, we have not discussed plans for the 425 yet but that doesn't mean we will not produce one"

Night Wolf
10-01-04, 08:34 PM
why woudl they say that? it is the same enigne....

... there are people who put the Edelbrock onto a stock 425 and had no problems... IIRC it saves 22lbs and gives it almost 20hp (on a stock enigne)

yeah, you could do work to the factory intake.... but it is just a crappy design for performance... the whole ow riser setup and eveything, although the owner of a machine shop was telling me that the reason it was made with the low riser intake manifold is to really help low-end torque.... but it kills the top end.... which from the way the engine performs, seems to be true...

10-09-04, 12:55 AM
For what it seems your doing try a stock duel plane from a 472 or 500
it works better than you might think

Night Wolf
10-09-04, 01:04 PM
So the stock intake manifold from a 472 or a 500 would work well? would that actually give it any extra power? I thought the intake manifold on all the big block Cad's were crappy... is it a low riser?... what year is best for it? Also, could my stock Qudra-Jet swap over without any problems? Thanks.

10-09-04, 06:44 PM

to answer your question
yes it is a low riser
yes it will bolt on
yes it will improve performance on a 425

it is bigger internally and has larger runners
What you can do and keep in mind this doesnt have to be done by a professional altho it helps is to open the middle of the plenum up under the carb.
youll be basically busting the midle of the intake out under the carb
If i could post pics here id post a couple.
For what you pay for a grungy used intake/cleaning it up/can of paint? and the mods to the middle youd have to try really hard to spend $100 and there would be no difference in performance between it and a edelbrock at the rpm range youll be operating at.
it works and you wont be putting money in edelbrocks pockets for nothing but the bling of a aluminum intake
good luck John

68' Big Body
10-09-04, 11:42 PM
Interesting? I just happen to have the stock Intake that I just took off of my 472 last week sitting in the basement taking up space. I switched it with an Edelbrock unit if you must know and yes it's alot lighter. The stock intake is 47 lbs, and the Edelbrock is around 25 lbs, so yes it's lighter. I also removed my non-working A/C, all of it and that's another 70-75 lbs easily. Does the car feel lighter...? You bet. Is it more powerful... I'd say sure, it jumps off the line now. If you want my stock intake though, it's your, just cover the shipping and I'll box it up and send it out, should be about $50.

See Ya,

10-10-04, 12:29 AM
*Psst* If Night wolf isn't interested, Do you think you could do the same for me? :P I have no problem with paying the shipping and a little bit of the price for the Intake too :) This is all of course if He's not interested

10-10-04, 12:55 AM
isnt the 425 manifold a single plane? which would be a better performance manifold the 472/500 manifol or the 425sp??ported not ported??spacer 1''or 2''??which would b the best combo for performance??

10-10-04, 02:27 AM
The best and least expensive would be the 472/500 dual plane
do the plenum mod like i described (couple hours work at the most)
if you have the room add a 1/2 or 1" OPEN spacer on it.
It will run with the edelbrock for what your doing and from what im seeing
support of the board cost you less than $100
If you want some pics of the modification
contact luxhauler for my email addy or add@zoominternet.net and ill be happy to send you a pic.
It works :thumbsup:

Night Wolf
10-10-04, 11:20 PM
hmm, I am very interested in this...

are all the 472/500 intake manifolds the same? the Edelbrock only flows better for high RPM use? makes sense though, my car is basically stock... I drianed the catalist beads from the cat yesterday.... so there will not be much high RPM going on... I will say though, I can't beleive what a differnce the cat made.. right now I still gon't have the hole plugged up, so there is a (big) exhaust leak... but no more rotten egg exhaust smell, and the car actually puts me back in the seat as she accelerates thru first....

my AC isn't working (leak) but I am going to save everything becuase one of these days, i woudl like to get it working agian.... I assume my A/C compressor will bolt right onto the 472 intake?

the lighter intkae manifold and no AC in (the '68?) really made a big differnce? hmm.. that is only about 150lbs... the car weighs 5,200lbs or so... almost a full tank of gas :) when I had the 400lbs of NorthStar in my trunk, I could hardly feel the extra weight while accelerating or slowing down...

The intkae is the stock manifold from the 472? if so I am very interested, that is very nice of you aswell... drop me a line at InoventionsEast@optonline.net and we can make arrangements :)

Night Wolf
10-10-04, 11:23 PM
the 1" spacer... is that a carb spacer?

I had bought a 14" open element air filter... ended up returning it becuase it woudln't cler the A/C... then I relaized I could have got a spacer for it... oh well.. I can always get it again...

10-11-04, 12:07 AM
yes I was talking about a carb spacer sorry about the confusion


10-13-04, 01:15 AM
yeah that 14" open filter really helps adds to the sound to but you'll need a spacer kit from mr. gasket available at any parts store it has a bunch of plastic ring spacers form 1 to 2" tall I think if i remember correctily it takes about two inches for the edelbrock 14" to clear the compressor plus you'll need a longer stud for the wing nut