Hello all, just joined and hope you can help. I have a Land Rover Defender with a Chevy TPi engine, a company called Overfinch used to do conversions here in the U.K.
I would love to know more about the engine and also I want to upgrade the spark plugs. Would NGK TR55IX be correct for this?
Thank you for any help
James

 

89 and newer TPI. (Speed density)

Block casting shows 96 and up Vortec? That seems kind odd.

 

They may have used a new crate motor and a used TPI system.

GD

 

It should be all new parts, I think they started doing the conversion in 1997 and this one was about 2002.

Anyone able to advise what iridium plugs to fit?

thnaks

 

I have ALWAYS used AC Delco plugs for my original TPI engine. Although, If you have vortec heads to go with that block, I can't say what plug would be best. I'm sure AC Delco offers something.

 

I don't think we get AC Delco over here.
do you know how I would identify if it's a vortec head?
Many thanks
James

 

If you can get Champion plugs, try RV15YC4.

Short of that, NGK 3547 should work. They're only £562.81 there:

 

Holy crap, that's INSANE.

 

You could always pull a valve cover and get the casting number. ...or a picture (if possible) of the cast "humps" on the front of the head. ...also, I think the manifold bolts go in straight up and down. Meaning 90* from level ground. Where regular heads thread in at an angle.

 

There would also be just 8 intake bolts, 2 at each corner and none in the middle.