5.7 liter Caddy engine swap or 5.3 Chevy engine?

[nitne]

Has anyone swapped a 5.7 liter caddy engine into their 67-72? I have searched the forums but can't seem to find anything. I have the option of going with the 5.7liter with trans and all other parts for around 2k or a 5.3 liter with all related parts for the same amount. What would you guys do?

[68Gold/white]

What year is the Cad engine, what model of Cad???

[Caddylackn]

Cadillac never made their own 5.7 liter motor, but they did put Chevy 5.7 and Olds 5.7 motors in some Cadillac cars starting in the 80s.

I would think you would be happier with a 5.3 LS motor than the 40+ year old 5.7 (350) that made only 180 - 200 hp when it was new. $2k seems high for a 5.7 unless its a fresh rebuild. The only 5.7 that's worth having would be the Vortec headed 5.7 that came in the Escalade from about 96 - 2000 with about 260 hp and good torque output but that would have a four wheel drive transmission.

[57taskforce]

Originally Posted by Caddylackn

Cadillac never made their own 5.7 liter motor, but they did put Chevy 5.7 and Olds 5.7 motors in some Cadillac cars starting in the 80s.

I would think you would be happier with a 5.3 LS motor than the 40+ year old 5.7 (350) that made only 180 - 200 hp when it was new. $2k seems high for a 5.7 unless its a fresh rebuild. The only 5.7 that's worth having would be the Vortec headed 5.7 that came in the Escalade from about 96 - 2000 with about 260 hp and good torque output but that would have a four wheel drive transmission.

‘99 was the first year for the Escalade, only 99-2000 have the L31 vortec 350.

[LS short box]

I would do the LS in heart beat.

[54blackhornet]

Why not a 500 ci Caddy ? Been done often so not a problem installing it, big time torque.

[jimijam00]

Neither. Spend that 2K on building an old school big block.

[70STOVEBOLT]

Originally Posted by jimijam00

neither. Spend that 2k on building an old school big block.

this

[Big Kev-O]

I have a 5.7 L31 similar to that caddy that I scored for $650 without a transmission. It looks more period correct but a 5.3 could easily make the same power while getting better MPG. That said you would need engine mounts & harness work to get the 5.3 installed. If the 5.3 & transmission has low mileage $2k is fair. Crate engine prices have gone way up and rebuilding a big block is going to cost way more than $2k. I would go with the 5.3

[nitne]

This is a 5.7 LT1 out of 1995 fleetwood with 134k, its the entire car, so I would have the trans, ECU and wiring harness and all the other bits I might need. Then I can part or scrap the remainder of the car. What do you guys think?

[kwmech]

I'd pass on just the ignition system on that thing alone

[titan1587]

5.3 all day long for the long distance reliability and mileage

[kwmech]

Originally Posted by titan1587

5.3 all day long for the long distance reliability and mileage

Yup, convert to something that has some long term support to it, instead of 'yeah I need a coil pac for a 95 cadillac, yeah the one with the coil and plug wires under the water pump'.

fastest pic I could find:
https://www.ebay.com/itm/32466886685...RoCkgIQAvD_BwE

[Big Kev-O]

That LT1 has 260hp and is a reverse coolant flow Gen II with Optispark ignition. It is a reliable engine but optispark has some issues. There are solutions available to solve the optispark issues. The 5.3L makes 270-310hp depending on what it came out of. In stock form the performance specs are fairly close so if you don't plan on modifying your engine either will get you down the road. I would not spend $2k on a Gen II LT1. If you are considering modifying for more HP the 5.3 LS would be my choice. There is a huge market for LS performance products.

[nitne]

Thanks guys, I will start looking for a good donor vehicle. I will start looking for 5.3 L from a 2 wheel drive truck, van or car. Is there any years I should stay away from?

[hugger6933]

You wont find a 5.3 in a car well you could cause the mote carlos or impalas had them but they are not the same engine your looking for. One place to look is a NPR Isuzu truck they have 6.0's and 4L80E trans in them I have one sitting at my shop so I know. Also be sure you can trace the motor to the truck it came from unless you know the people you are buying from. There are tons of guys that think they bought 5.3 motors and really got the 4.8 motor instead. Once you separate the motor from the truck, you cant tell without pulling the oil pan and checking rods and stuff. The block even have displacement stamped on them but many years are stamped 4.8/5.3. The motor if still in the truck, the vin number will tell you the truth about the engine size. If you find one in a Suburban it will be 5.3 cause they dont offer the 4.8 in them. Hope this helps a bit. Jim

[Ziegelsteinfaust]

I am a pretty big LT1 guy, and I am swapping a 383 LT1 into my C10 tomorrow. If you like a carb vs fuel injection. The intake manifold is available, but a bit pricey. You can use your standard V8 distributor with a hardened gear swap. With the 4 barrel intake, 1 3/4 headers they are a very strong 325hp engine. Factory exhaust, and intake were big comprises. You can go over 400hp with a cam, but 425 is the limit due to cylinder heads. Go afr, and 500 is pretty easy.

True it is no LS, but it is not a weak engine. I had a LT4 with performance build of unknown specs. It was from a dyno shop who was prototyping parts for Corvettes. It would idle like a baby with a mild lope, and could seriously hang with most things one would actually see on the street.

To put one in a C10. The B body accessories are the best supposedly. I only ran alternators on modified brackets. You just need to notch your cross member. How much I will find out in several months when I add AC back to my truck

[truckster]

Originally Posted by Big Kev-O

That LT1 has 260hp and is a reverse coolant flow Gen II with Optispark ignition. It is a reliable engine but optispark has some issues. There are solutions available to solve the optispark issues.

As the proud owner of an LT1 Z/28, I can tell you those Optispark solutions aren't cheap. You could get an entire LS engine for what a 24x Optispark conversion costs.

[gmc684x4]

Gen 2 Ltd distributors suck
Hit a puddle hard they fail
Plan on replacing it atleast every 2 years
It will be obd1.5 which is obd1 wiring with obd2 port scan tools usually won't read it with out rewiring it

I had a 94 z28 loved it until I learned the issues with the poor dizzy design

For anything more then free I would give it a hard pass
Look for its son gen 1 vortec l31 or better yet find a 4.8 5 3 or 6 liter

I got a good l31 free in a van and a good 5.3 in a truck there out there