Well heres the deal. I can get an 87 coupe deville for free. It has an automatic and digital dash. I am new to cadillac. My girlfriends dad just wants it gone. It has the 4.1 i belive and he said its blow a head twice. Should i
1.get a new 4.1
2. rebuild it
3. get a 4.9 (i think) if a 4.9 is the way to go what all would i need to get (computer, pumps, blah blah blah)

I am interested in getting at least 20 mpg.


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Moderator Edit:
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Hey Nick, the other engine in the 1987 was the 5.0 (307) I believe it was an Olds. engine. Not sure what the changes required would be , perhaps Slowroll could chime in and tell you that. You would be at an extra 10 - 20 hp with the 307, but 4bbl, not DFI.

 

How about an '87 to '88 Allante 4100 engine for next to nothing?
more hp, same block, high performance internals.

 

thanks for the replies, but i still need to know what else i would have to get for that. Computer, tranny? it is front wheel drive

 

Every Allante is FWD.

4100s are identical in everyway except some of the inners for higher hp.
For various reasons, I would not use a pre-1985 4100 - Allantes are only 1987 and 1988.

You can also use an Allante 4500 (1989 to 1992) if you use all the accessories from your 4100,
including manifolds, emissions, etc.

If you also take the trany, you may also need to bring over the computers for proper shifting.
If you really get serious, we have a TECH, allantesource, that does nothing but Allante stuff.

It all depends whether you want to stay at around 125 hp or go to either 170 hp or 200 hph.
Once you go to the other engines, like the 4900 or the 307 , you are most likely looking at more
items, computers, etc.

 

You will need to stay with all your modules and emissions gear no matter what you do. The 4.1 or 4.5 engines will work, There will possibly be a problem with the way a 4.9 runs, as it has 20% more displacement and the amount of fuel programmed might not be what it needs.We have already replaced an Allante' 4.1 with an Allante' 4.5. I have also sold an Allante' 4.1 to someone who installed it into an '87 Coupe Deville. Both projects came out fine.We can give you a great deal on an '87 Allante' 4.1 that wejust pulled. It had about 115k on it, ran great, but the car was hit very hard in the rear during a police chase. $250 plus shipping. To use the Allante' 4.1, you will need to change the intake manifold and use your exhaust manifolds and other emissions equipment. Or we've got a nice running4.5 out of an '89 Allante' for $500 plus shipping.

 

Sorry not mechanicaly inclined. my buddy will do all the work when i get the stuff together. So i am going to go with the allante 4.1 . Everything is the same?? Less likely to blow head gaskets? I only need to swap manifolds if i go up to a bigger size correct? I am gona call a few places so i need to know what all to ask them for. just to block or everything. Will my computer stuff still work like mile per gallon and stuff like that?
If you could just make a list of anything that will NOT be a dirrect swap.


Price the shipping of 4.1 to zip code 68505, we may have a deal. What all will that engine come with??

 

Think of the Allante' engine as a long block. You will need to use your intake and fuel injection, probably your oil pan, your exhaust manifolds and "Y" pipe and oxygen sensors, your starter, your alternator, your modules, your emission control devices, etc. The timing cover and water pump are the same. The motor will need to be delivered to a place that can unload it, not to a residence. The only time I have seen head gaskets blow is if the car is overheated. Once the car has been overheated to the point a head gasket blows, it is best to replace the engine

 

that allante 4500 is like 200 hp vs his old '87 4100 at 120 hp?

 

Gotta tell you, THAT has to be the best $$ / $$$ increase in hp and engine reliability that you can buy.