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1992 Town Car Cartier & 2014 Accord LX MTX
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Discussion Starter #1
I was thinking last night about Broughams, and the series of motors they've had: 425, 368, HT4100, 307, 305, 350. And I got to wondering why they never threw in the 4.9 to make it "Cadillac Exclusive" like they had pre 1986. My first idea was because the 305 and 350 provided adequate power (especially the 350) and they were easy bolt ins for that chassis. But when you think about it, the 4.9 makes much more power and torque than the 305, and the 4.9 makes 15 more hp than the TBI 350, and 25 less lb/ft of torque. I know that the HT4100 was made in transverse and longitudinal (sp?) configurations, would it be possible to mount the 4.9 in the longitudinal (sp?) way?
 

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My guess is Cadillac just didn't want to spend the money on designing a Longitudinal version of the engine since they already had rather bad press from the HT4100. A tried and true engine was most likely their safest bet.
 

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Discussion Starter #3
yah probably
What would they have had to redesign to make it longitudinal?

What happens to their old designs after they stop making them? Do you think they still have the "blueprints" ( I dont know if thats the correct word) for the 500, and the 472 and the 368???
 

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'80 Fleetwood Coupe, 1994 and 1995 Mercedes 140 Coupe
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Cadillac expected the old RWD chassis to go the way of the dinosaur. It was kept alive because of consumer demand. They took a double hit. First with the 8/6/4 and then with the HT-4100. You really can't blame Cadillac for going conservative after that. :bonkers:
There was a guy who was making 4.9's to fit in RWD cars. I suppose he used the HT-4100 block with 4.9 sleeves and crank+ other parts. Don't see why it wouldn't work. I have a hunch that the FWD 4.1's were a little stronger than the RWD ones and may have been able to live longer. They have a different bellhousing and intake manifold + external braces. That would make a RWD 4.9 an engine that might not last too long. Dunno for sure. Just my feelings from watching what lives and what dies. :hmm:
 

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Discussion Starter #5
Interesting..... It seems to me that the little aluminium V8's wouldnt be able to handle the weight of the Broughams, and you would need atleast a 350 to haul that much weight around...but thats just the way I see it.
 

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94 FWB, 93 SDV, 94 FWB (sold), 90 Brougham (sold)
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It's definately an interesting idea. Personally though if you're willing to take the time to longitudinally mount a 4.9, it would be more beneficial to just do the 350 or BBC swap. Still, the uniqueness of having a 4.9 Brougham would be pretty interesting. The gearing would have to be changed a little bit, but it would be neat to see.
 

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70 Fleetwood, 87 and 90 Brougham, 94 Fleetwood
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I had given that some thought when I first began to cosider the project for my '85 Eldorado.

There are many obstacles that would have to be overcome, and given the resources that I have, it would have been impossible.

First, the 4.9 was available only in the transverse application. Not only were the block castings differant, but the crank is also differant. The nose is some 1 1/2" shorter, making it unsuitable for the accessory mountings of the longitudinal engine. As you know, the 4.9 is a stroked 4.5.

Also, all 4.9's use the larger port heads. In order to reap the benefits of the larger displacement, these heads should be used, but there is no corresponding longitudinal intake. A serious port mismatch would result. As well, all 4.9's were port injected. So to match the fuel requirements of this engine, a proper manifold would pretty much have to be fabricated from scratch.

A 4.9 with the small port heads would be somewhat compromised. Additionally, all cams used in the 4.5's and 4.9's emply roller lifters. Because the lifter valleys are differant in the 4100's and 4.5's, you could not use these cams either.

So, I decided to go with the 4.5. It is a simple matter of dropping in the larger liner/piston assemblies. Form all that I have read, the ECM will compensate for addition displacement and any altered demands on fuel.

Some rebuilders offer this upgrade when you are purchasing an engine as well, and I feel it is a worthwhile upgrade.

Mike
 

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Discussion Starter #8
You're making a 4.5 '85 Eldorado?!
Cool!
The 79-85 Eldorados are some of the best looking Caddies ever, but the motors they had from 82-85 dont do the car justice.
Would a 350 LS6 fit? I know they had a 350 in 1979 and 80, but I think that was an Oldsmobile 350. I've always wanted to throw in a LT1/LS1/LS6 in one of these and leave it FWD, but I was never sure if it was possible.


Could one put a N* in a Brougham????
 

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Guidematic, you do know that the 1987 castings of the 4100 were actually early castings of the 4.5 block. They have the roller cam hold downs but they are not drilled. Does the 85 eldorado have the same 4100 block as the uni-body cars? Or is it longtudinal block? I still like your idea of putting the 4.5 sleeves in the 4100, but it would be nice to have the roller cams also.
 
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