[N0DIH]

There is an article on how to make a 307 scream in one of the latest mags, 500 some hp.... Not streetable in a heavy car. But they used the 5A heads too.

If I was itching to do an engine swap, I just found a couple 5.3L truck LM7's for $400 each. BOTH with under 50K miles. That is like a new engine. $ for $ you can't beat it. Yes, some work to put in, the biggest headache is the oil pan, then the wiring and fuel pump. But nothing insurmountable.

Lets think of it this way, the LM7's move a 5.3L to around a 16.0 quarter mile or slightly better with a 5000 lb truck, and a friend of mine towed 9000 lbs all the time with his with an effective 3.42 gear (with our tire sizes, he had 3.73's). If you are swapping in a gear 3.73's would be a wonderful gear in a Fleetwood/Brougham. So you are faster than the best 307 GM ever made, can tow with a LT1 V4P, probably out run an LT1 with relative ease and knock down excellent fuel economy.

If anyone has looked, the car manf have gone to GEAR to move the cars not torque. Peak torque is where best mpg is, but the more torque is more fuel used. So we have gone to let more gears and shorter gears get the car moving and still give excellent performance.

 

[ramos7]

the gearing has crossed my mind. at one point in time i thought swapping in 4:10 gears from a chevy truck to see the results but in this economy i havent been able to play with my toy lately

 

[N0DIH]

With the 307? It will help a lot, but then you will find how small the cam is. Then you could simply toss in a 307 HO cam or find an Olds roller grind that works ($$). I can find out what is out there.

If you can go back to non roller lifters (might be able to using Mopar lifters) you can get a better grind that would better suit the 307 and 4.10's.

Toss on some old 5A heads ported and milled to get comp up would help too.

It will never run "right" as it is just a small engine....

the gearing has crossed my mind. at one point in time i thought swapping in 4:10 gears from a chevy truck to see the results but in this economy i havent been able to play with my toy lately

 

[steelybill]

A stock rebuilt '76 500 made 302 hp on a dyno test, The specs in the aftermarket manuals, like Chiltons etc, is less than 200 HP because of the standard being changed in 1972, to rear wheel HP with all accesories operating. Don't know how the new engines are rated.
The 400 HP of the '70 Eldo is a myth. Valve float wold take over before it ever got to the RPM the factory claimed. It did look good on paper though. Typical of manufacture's claims.
The '76 500 is a good engine though, and likely the last good one that Cadillac designed. It does like gas very well, and it's a torque monster, and a transmission like a 200-4R will not live long behind it.

 

[86fleetwood541]

I am trying to figure out this same thing and sofar what ive got from chris I beleive his name is at cad500parts is with their engine mount kit an eldo oil pan and the headers off a a 475or 500 from a deville or any cad but the eldo and a chassis mount oil pomp and a phew other small changes this engine is a direct bolt in for these cars (fleetwoods of the 80)

 

[86FLEETWOOD]

I now have a 350 olds motor from a 1976 cutlass. Do i need its tranny also or can it go to my original tranny

 

[N0DIH]

Original will be fine. But not strong, don't abuse the OD trans with the Olds 350....

 

[The-Dullahan]

I have seen a 1980 Fleetwood Brougham with a 500 in it. Your car is generically, basically the same.

http://www.mcsmk8.com/80CAD-500/MAVICA.HTM

 

[86FLEETWOOD]

now i have someone searching for a motor for my caddy. i have been looking into an olds 350, 403 or the pontiac 400. these motors are being salvaged out of 70's model cars. which one if any would replace my 307.

 

[86fleetwood541]

the oldsmobile 350 403 and 455 will all be bolt ins although the 455 sits around 1 inch higher because of the intake and can cause clearence issues the 403 and 350 dont cause this the cadilac 425 472 and 500 will all go in your car however you will need a different transmission driveline and rear end the drive line might work with different yokes from what I understand however the rear end needs switched because it is a full in smaller a 7.5 vs an 8.5 out of the earlyer years the 7.5 wont handle the kind of torque you would be putting to it plus the gears are wrong for the 400 tranny you would want to handle the torque btw everything bolts in except engine mounts but you can buy a mount kit for our car from flashcraft(cad500parts.com) for 95 dollars plus shipping I personally am installing a 472 in mine or will be shortly i should say however the oldsmobile engines will be the easiest direct swap If i whent that route I would go with the olds350 get some head work a mid performance cam exhaust and a stage 2 master rebuild kit for that 2004r so it will handle the power from the 350 I would get the tranny kit even if I didnt have any work done to the 350 anyway google 2004r raptor transmission they sell rebuild racing kits for the 2004r allowing it to supposably handloe 800+ ft,lbs. of torque

 

[N0DIH]

don't knock the 7.5" too much, it lives behind LS1's in the F-Body cars.... Just don't tow or put slicks on, allow it to smoke the tires if it does, when you load it up with traction, that is when things break....

I have a 8.5 3.08 open 9C1 axle (rear discs) for sale if you are interested though.....bolt in for any 77-up B/D body.....

 

[86FLEETWOOD]

I kow have a chevy 350 w/ the 700 tranny. Gonna put it in my cadillac this weekend. Anyone knows how long it should take and what i should be faced with?

 

[Anthony emanon]

If it was me? Go spend $800 on a used 5.3L LM7 out of a newer GMC/Chevy truck. Get the trans too. It is a bigger swap, but you will LOVE it.

Why use old engines that struggles to get to 300 hp when a 5.3L is 300+ out of the box.

If fuel economy is more important, a 4.8L is a bit better, but being they make less of them, probably more expensive.

If power is the game, then get a 6.0L LQ4 or LQ9.

Yes, these are a bigger project, but if you are wanting a modern high fuel efficient engine that will keep your Cadillac living on forever, this is the investment I would seriously look into.

Car-part.com and look up a 50K mile engine or so, you will be surprised how inexpensive they are compared to doing something like an LT1 or L05 or an Olds 350 swap. Not as easy, but far more rewarding.

So I've got a 93 brougham I've gotta deal motors currently looking can you give more info about the motors and swap your talking about because this might be the way I go

 

[Submariner409]

Welcome to CF !!! This thread has been dead for 11years and the member to whom you replied has not logged in for 2 years. You may not receive an answer.