Astrak Posted April 3, 2008 Report Share Posted April 3, 2008 Are there any known problems with the 425 in a 1978 Cadillac Deville? Link to comment Share on other sites More sharing options...
Texas Jim Posted April 3, 2008 Report Share Posted April 3, 2008 Are there any known problems with the 425 in a 1978 Cadillac Deville? I had a 78 DeVille that I bought new, that I ran for over 150,000 miles. Put one alternator amd one water pump on it. It was a great car. Used no oil and ran strong. Also had a 78 El Dorado (bought used) that had over 100,000 when I sold it. It was still running strong also. Of course someone else may have had different experiences with the 425, but I liked them. Link to comment Share on other sites More sharing options...
tomrno Posted April 3, 2008 Report Share Posted April 3, 2008 Are there any known problems with the 425 in a 1978 Cadillac Deville? Have had a '78 Coupe DeVille since '92. The engine seems to be bulletproof. One waterpump replacement, one fuel pump, (done by me) in all that time. Not bad hwy mileage : in town brutal. Link to comment Share on other sites More sharing options...
Ranger Posted April 3, 2008 Report Share Posted April 3, 2008 They're very thirsty! Link to comment Share on other sites More sharing options...
Texas Jim Posted April 4, 2008 Report Share Posted April 4, 2008 Don't know if they still sell them or not... but Holley made a spreadbore replacement for the Quadrajet. You could re-jet it for better mileage in town. I did that. It still wasn't anything to brag about, but it was a lot better than the original Quadrajet. Link to comment Share on other sites More sharing options...
Ed Hall Posted April 4, 2008 Report Share Posted April 4, 2008 Believe it or not, the Quadrajet is a very good carburetor, probably still one of the best out there. It is still being made today by a company called Edelbrock. The Q-jet carb is known by the racers for being very tunable for precise air to fuel mixture. But for this to happen, it needs to be dialed in by someone who really knows these carburetors and can put the car on a dyno and dial everything including timing advance as a unit. With the price of fuel these days, it might not take long to pay back the cost of doing this work. Link to comment Share on other sites More sharing options...
95SevilleSLS Posted April 4, 2008 Report Share Posted April 4, 2008 Believe it or not, the Quadrajet is a very good carburetor, probably still one of the best out there. It is still being made today by a company called Edelbrock. The Q-jet carb is known by the racers for being very tunable for precise air to fuel mixture. But for this to happen, it needs to be dialed in by someone who really knows these carburetors and can put the car on a dyno and dial everything including timing advance as a unit. With the price of fuel these days, it might not take long to pay back the cost of doing this work. I like the Edelbrock carbs. When I did some beefing up to my 84 suburban, I put on a higher CFM Edelbrock and actually ended up with better mileage. I'm not a big fan of holleys. The people that I know that have put them on say they get crappy mileage with them. -Dusty- - 02 Seville STS, white diamond - 93 Sixty Special, Tan with vinyl top - 79 Coupe DeVille, Tan with Tan top - 06 GMC Sierra Z71, Black - 92 Silverado C1500, black and grey - 83 Chevy K10 Silverado, Black and Grey Link to comment Share on other sites More sharing options...
Ed Hall Posted April 4, 2008 Report Share Posted April 4, 2008 I like the Edelbrock carbs. When I did some beefing up to my 84 suburban, I put on a higher CFM Edelbrock and actually ended up with better mileage. I'm not a big fan of holleys. The people that I know that have put them on say they get crappy mileage with them. Edelbrock makes their own carburetor based on the Carter and a more expensive one based on the Q-Jet. What's nice about the Q-Jet made by Edelbrock is it doesn't have all the choking pollution devices. Link to comment Share on other sites More sharing options...
95SevilleSLS Posted April 4, 2008 Report Share Posted April 4, 2008 I like the Edelbrock carbs. When I did some beefing up to my 84 suburban, I put on a higher CFM Edelbrock and actually ended up with better mileage. I'm not a big fan of holleys. The people that I know that have put them on say they get crappy mileage with them. Edelbrock makes their own carburetor based on the Carter and a more expensive one based on the Q-Jet. What's nice about the Q-Jet made by Edelbrock is it doesn't have all the choking pollution devices. I think I have the one based off of the Carter if I remember right. I was/am very happy with it. I think they are a good company. I bought the intake to go along with the carb and that was Edelbrock too. -Dusty- - 02 Seville STS, white diamond - 93 Sixty Special, Tan with vinyl top - 79 Coupe DeVille, Tan with Tan top - 06 GMC Sierra Z71, Black - 92 Silverado C1500, black and grey - 83 Chevy K10 Silverado, Black and Grey Link to comment Share on other sites More sharing options...
Texas Jim Posted April 4, 2008 Report Share Posted April 4, 2008 I have built some good Q-Jets. You can buy different fuel metering rods for the primaries and the vacumn operated secondaries can be converted to progressive, mechanical linkage, if desired. For street cars... big block 400's and up... I have always liked the "StreetMaster" intakes from Edelbrock and LONG COLLECTOR headers from Hooker. Gives you good low end torque. That was several years ago. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.