Saw a post on fb where dude said some '95 SC's have thick rods. Said you can tell by the fuel rails......round cast rails means thin rods, billet square rails means thick rods. Somebody clarify this for me please.

 

All non turbo VVT-I engines have thin rods

All non vvt-i AND 2jzgte VVT-I have thick rods.

This is the only motor with "thin" rods that comes on 97/98+ motors.

 

^^ This.

1992-1997 2JZ-GE Non-VVT-i = thick stock rods just like stock 2JZ-GTE's

1998-2005 2JZ-GE VVT-i = thin rods (must be upgraded for boost)

2JZ-GTE Non-VVT-i AND 2JZ-GTE VVT-i = thick stock rods

Also... 1JZ-GTE Non-VVT-i and 1JZ-GTE VVT-i both have their own thick boost-friendly rods.

For all of the thick factory rods: With stock rod bolts they are safe up to 500whp. With an upgrage to ARP rod studs + nuts and installation by an engine machinist who makes sure the caps are adjusted for the ARP nuts so as to not tighten out of round... good up to a maximum ceiling of about 700whp with the stock thick rods assuming a good healthy tune.

Similarly the factory 2JZ-GE VVT-i pistons and rings are not considered good for boost applications.

1992-1997 2JZ-GE non-VVT-i 10.0:1 pistons and accompanying stock rings are high quality hypereutectic semi-forged from the factory just like 1991-2005 2JZ-GTE high quality hypereutectic semi-forged 8.5:1 pistons with quality rings. The higher compression GE Non-VVT-i variants need a lower compression MLS head gasket for boost but BOTH of these pistons are good for up to a max application of 700whp (with a good quality tune).

All 2JZ blocks (and 1JZ blocks) are equally strong thick nickel content iron castings. ALL 2JZ and 1JZ crankshafts are forged and equally strong.

If you'll be building a 2JZ block for 600whp-700whp++ right out of the gate as a *starting* point then forego all factory rods and go with stronger aftermarket billet or forged rods and forged 2618 aluminum or forged 4032 aluminum pistons. Usually its 2618 forged pistons that are available for JZ engines. A good rule of thumb is to consider all this and build your engine with a little more strength than you actually need.

 

I guess I should have specified this fb post was in reference to 1UZ specifically not 1J or 2J

 

According to CartuneNZ......square billet rails, coil lead pointing straight up (vs facing forward), large (19mm) breather connector on passenger side valve cover and fuel pressure regulator in front of throttle body = thick rod motor. My 95 checks all those boxes.

 

Ah! In that case... technically 1989-1994 1UZ-FE factory connecting rods are the thickest and strongest of all that Toyota themselves made.

See the image below for a comparison of each con-rod revision to the 1UZ series and see the source of this on the Lextreme's site for far more in depth details:

https://www.lextreme.com/comparing-l...d-h-beam-rods/

 

Just keep in mind the thickness isn’t the only factor the effects strength. The metallurgy can have a big effect on also, and many of the thinner rods in that photo are forged, so almost as strong with a lot less weight.