I'm restoring a GTU z car and looking for a source on allowed modifications for a 1978 car. Wheel size, ignition, trans, brake calipers etc..

Thanks

Except for some IMSA specific class and safety items, the allowed mods for GTU were basically FIA Group 4 regulations. You can order the FIA homologation papers from ACCUS. You need specification 3023 and ask for the addendums for the 280Z for 1975. FIA Historical Technical Passport (HTP) -- Purpose and Acquisition

Les at Classic Datsun might be a good souce for information on this build.

some references:

BSR-260Z-IMSA Photos by psanders240 | Photobucket

Authentic Bob Sharp ?75 Datsun IMSA GTU Z-Car | Bring a Trailer

IMSA GTU Datsun 240 Z Race Car Restoration | The Car Build Index

BOB SHARP RACING DATSUN, Paul Newman..Combinaison gagnante

https://dattosankureiji.wordpress.com/2013/02/18/pantazis-family-bob-sharp-racing-imsa-260z-replica/

Datsun 240z, 260z and 280z IMSA style race adjustable outer tie rods

'70s Spirit: The Imsa 240z | Speedhunters

Thank you to everyone that has responded. The information gives me a good starting point.

Terry

Here's another one: https://sites.google.com/site/zlalomz/imsagtuz