Well I was talking to Edahall through PM about this (his inbox is full so I couldn't continue the discussion). I was wondering I you could install the intake manifold from the Allante 4.5 to the Eldorado's 4.9 with little modification (Edahall mentioned the master cylinder would cause a slight problem with the intake hose) which you can solve with a little creative thinking. Though all I really want to know right know (I have biger things to do on the car before I would do this) is
A. Is it possible with in reason (i.e no excessive customization of parts and such) to install.
B. What would I gain as far as HP (I would think some just because the intake looks like it allows more air flow than the Stock 4.9's but what do I know):D

No, you would probably loose some power with this intake manifold if you just stuck it on. These intake manifolds sacrifice some power in the lower rpm range to make more power in the higher rpm range.

These intake manifolds are made to make more power in the upper range above 4500 rpm. The 4.9 heads don't do well above 4500 rpm because of design and the computer in your car doesn't allow the engine to rev any faster than this.

If you wanted to make it work, you would need to also use the Allante heads or modify your heads. You would then also need to reprogram your PCM to change the shift points to a higher RPM.

ok then I'll save my money thanks man.

Have you modified your exhaust and advanced the timing several degrees? Those 2 things help out a little.

No but I've only had the car for about a week and a half and their are more important things to be done on it in the immediate future (brakes, main seal, power steering leak) but I do plan on getting a throatier exhaust to free up some HP as well as possible rig up a straight runcold air intake to replace the curves and twist of the factory intake hose, but thanks for the help Edahall.

If it's not leaking around the hoses, the power steering leak might very well be from the steering rack. Mine started leaking at about 180k miles when the car was about 15 years old. I ended up installing a rack out of an STS with fast ratio. I think it was a major improvement in steering feel.

For my exhaust, I cut out the old muffler and fitted a Flowmaster model 50 Deltaflow using adapters. It only took me about an hour to do the job. I like this muffler because it is throatier but didn't make any more noise inside the car with the windows up.

I've heard mixed results with modifying the intake. If it's designed correctly, you might gain a couple horsepowers but most of the time, most people loose power but think they have more power because of the added noise.

i have a 3" intake on my 4.9 it was a noticeable difference, i also have a flowmaster 80 on also

i have a 3" intake on my 4.9 it was a noticeable difference, i also have a flowmaster 80 on also

Did you take it to the dyno or test it on the track? A lot of times, people mistake the added noise for extra power.

If it's not leaking around the hoses, the power steering leak might very well be from the steering rack. Mine started leaking at about 180k miles when the car was about 15 years old. I ended up installing a rack out of an STS with fast ratio. I think it was a major improvement in steering feel.

For my exhaust, I cut out the old muffler and fitted a Flowmaster model 50 Deltaflow using adapters. It only took me about an hour to do the job. I like this muffler because it is throatier but didn't make any more noise inside the car with the windows up.

I've heard mixed results with modifying the intake. If it's designed correctly, you might gain a couple horsepowers but most of the time, most people loose power but think they have more power because of the added noise.


yeah the rack is leaking but it's a little to cold (-28) to have it done untill spring but I'll get the brakes and main seal fixed first cause thats a saftey and reliability issue.