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

[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.

[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