: L37, ld8, l47 & lx5



Cadillackostab
10-08-11, 09:14 PM
Just had a couple of questions about the 3 Northstar v8's. Tried looking for this information on the search bar but could find nothing.

In The 1996-99 Northstar L37 & LD8 basically the same besides the difference between the camshafts. (internals, head flow, Block strength, Valves & Springs ect).

In The 96-99 L37 4.6l & l47 4.0l Are those basically the same besides the camshafts & that the 4.0l is a smaller bore. (Internals, head flow, Valves & Springs, block strength)

Is It possible to swap the l37 cams & valve springs into the l47 4.0l engine & also would it be possible to put a l37 heads on a l47? Is it possible because of the bores are different.


I've heard that with a L37 cam swap in a l47 4.0L hp will go from factor 250hp to around 320hp?


I just really wanted to know if any of the v8 Northstar parts can be swapped.


And last but not least for the 3.5l lx5 have you guys heard of anything crazy like adding a turbo or sc to it to make more hp or even. Or even bumpin up the compression ratio since its only 9.3:1. Are the internals forged just like the other northstars if anyone has any links to learn more about the internals of the northstar i'd appreciate it.

Submariner409
10-08-11, 09:53 PM
Just had a couple of questions about the 3 Northstar v8's. Tried looking for this information on the search bar but could find nothing.
In The 1996-99 Northstar L37 & LD8 basically the same besides the difference between the camshafts. (internals, head flow, Block strength, Valves & Springs ect).
In The 96-99 L37 4.6l & l47 4.0l Are those basically the same besides the camshafts & that the 4.0l is a smaller bore. (Internals, head flow, Valves & Springs, block strength)
Is It possible to swap the l37 cams & valve springs into the l47 4.0l engine & also would it be possible to put a l37 heads on a l47? Is it possible because of the bores are different.
I've heard that with a L37 cam swap in a l47 4.0L hp will go from factor 250hp to around 320hp? (1)
I just really wanted to know if any of the v8 Northstar parts can be swapped. (2)
And last but not least for the 3.5l lx5 have you guys heard of anything crazy like adding a turbo or sc to it to make more hp or even. Or even bumpin up the compression ratio since its only 9.3:1. Are the internals forged just like the other northstars (3) if anyone has any links to learn more about the internals of the northstar i'd appreciate it.

1996 - 1999 L37 and LD8 are basically the same.

(1) You heard wrong.

(2) Couple of glitches here - pre-1996 engines are pretty much the same. 1997 saw some changes, 1998/9 saw more, and 2000 > was a total redesign. When swapping parts try to stay within the same year groups. There's a compatibility thread (sticky) concerning differences at the top of the Northstar engine Forum.

(3) The 4.6 engine crankshaft is not forged. (Cast nodular iron). The rods are forged/cracked cap units. Internals: see (2).

Cadillackostab
10-09-11, 12:39 PM
Darn too bad you can't change many parts onto the diffrent engine's like the l37 to l47. And has anyone heard of doing anything crazy with the lx5 its running 9.3:1 with only 215hp i wounder what would happen if u bumped it up to 10:1

89falcon
10-09-11, 01:58 PM
Darn too bad you can't change many parts onto the diffrent engine's like the l37 to l47. And has anyone heard of doing anything crazy with the lx5 its running 9.3:1 with only 215hp i wounder what would happen if u bumped it up to 10:1

Actually, IIRC, you CAN interchange parts between an L37 and L47 if they are the same year model............but why would you...they use the same cams.

Submariner409
10-09-11, 03:16 PM
Play with compression changes and you also have to play with PCM reprogramming - fuel curves, timing curves, knock sensor operation. (and try to find pistons - the quench areas in the pent-roof chamber already prevent milling the head.)