I remember a few months ago when all the talk of being able to put a 472 edelbrock manifold on a 425 was possible or not then some one said that you could put the stock 472 manifold on the 425 and it would perform the same as or better than the edelbrock with some modification well now I've got the 472 manifold so what do I have to do.

Remove the 425 manifold and clean and install the 472 manifold and have some fun.

will the 77 425 Q-jet fit with no problems and there is no EGR valve on the back of the 472 manifold but it has two small holes that come up to the bottom of the carb should I plug them?

Well I wish it was that simple I installed the 472 manifold on my 425 to day and here is a list of prblems I ran into
1. the A/C crompressor was 1/2 inch to short to fit between the brackets so I had to use washers to get it to fit
2. the carburetor choke catches on the side of the manifold to carb mounting area so I had to buy a special spacer type adapter plate from elelbrock how ever those two little holes I was talking about well one of them was sticking out the side so when I went to start the car there was a major air leak and the car wouldn't stay started without keeping my foot on the pedal a little ways so those will be getting pluged tomarrow with some steel putty or maybe some RTV
But it did start and it would run with a little help so just a little more work and maby it will be a driver again

well its on and running again and quite well I might add it definintaly improves acceleration but I broke the transmission downshift switch, pluged the two holes under the carb that were leaking exhaust so just need to fix the switch and all will be good

did you cut out the middle section or just put it right on?

just straight on but I fear that I may have created a serious problem see this 472 manifold was off a 68 and did not have the same EGR set up as the 425 it just had two holes coming up to the bottom of the carb and I plugged them with some steel putty because they caused an air leak at the bottom of the carb because they stuck out the side, well much to my disappointment I have learned that the EGR actually lowers the temp inside the combustion chamber and I noticed how much hotter the heater was blowing and the higher temp of the radiator hose so now I'm worried about over heating so tomorrow I'll do some highway driving and use a three hundred degree thermometer to check the upper radiator hose temp also now at idle there seems to be a slight lope its now as smooth as it used to be but its still pretty amazing that I can take a manifold from a 68 and stick it straight on my 77 and get better performance

Stick a temp guage in it, and if it stays below two hundred or so, you'd be just fine...

Ok everything is good now highest the temp got was 196F fixed the idle problem by routing the brake booster vacuum line to the location on the manifold where it was on the 68 so now the idle is smooth as glass with plenty of power to tromp on at a whim so heres a few pics of my 1977 Cadillac Sedan DeVille's 425 with valve covers and manifold from a 1968 472

Shweet!
That is purdy dude!

Kev

Kinda like what you did with the valvcovers on that...looks purty sweet!

nice!

I too have a 1968 472 intake manifold.. I am going to take it to the machine shop to have the center piece cut out, then I am going to install the 2nd Q-jet that I have (going to rebuild it first) and maybe put a carb spacer in it (still learning aobut them)

That engine bay is clean!

can you give alot of details about what had to be changed or moved with those extra holes.... I am going to be doing the same exact thing... excpet on a '79 :)

my engine bay currently... come Spring when it starts to get nice out... I am doing an extensive clean up on the engine and the engine bay along with replacing alot of cracked vaccum lines etc....

FL car most it's life... body is in great shape, but under the hood is rusty... car was rust proofed when new and now it is all flaking and stuff...

Although, compared to how it was the night I bought the car, it is ont he road to recovery :)

those PICS remind me of what my 77 looked like when I got it a few years ago not as much rust but the owner lived out in the country on a dusty road so every thing in the engine bay was just covered with grease and dirt but its taken me almost 2 years and about $1200 worth of new parts to get this car to where it is today but I saved a little doing it all my self I got the idea for the valvecover from the air cleaner off a 472 how it says cadillac 472 so I took a grill emblem off the front of a 67 deville along with the valvecovers from a 68 472 and cut the studs down off the emblem drilled a couple of holes in the cover and popped it right in then modified it so I could mount the cruse control in the stock location as for installing the manifold extra stuff I had to do to get it to fit was take the A/C bracket from the 472 swap it with the one from the 425 and put spacers between the bracket and compressor so it would line up with the belt then I had to use a carb spacer to raise the carb up because the electric choke sits lower than the bottom of the carb then I had to remove the brake booster vacuum line from the back of the carb and plug that because it messed with the idle and route it to the stock location on the 472 cadillac which is on the manifold and plug the two what looked like EGR holes on the top of the manifold because they stuck out the side of the carb and last was use one of the vacuum tees from the 425 manifold on the 472 for the distributor advance that was about I'll try to get some PICS of the whole car and interior tomorrow by the way those edlebrock 14" air cleaners look good on these cars also if you ever remove the hood insulation there's a big round gap in the hood structure that looks like it fits right over the breather

my hood insalation is becoming shadded carpet

I was going to get new insalation... or just remove the old stuff... I like it though, kinda cleans up the enigne bay...

ok I finaly got some pics of my 1977 cadillac sedan deville and a few more of the engine and the master cylinder

So I guess I should KEEP my 1968 manifold when I have the engine overhauled :lildevil: