964 3.6 vs 965 3.3t?

[klober23]

Thinking of building a 964 track car. Has anyone played with adding 965 turbo like setup to a 3.6? Would a 3.3 Turbo from a 965 be a better engine that adding a turbo to the 3.6 964? Experiences? Opinions? Thanks

[aws]

The stock 965 bases 3.3 turbo engine is fine as a "drop in" replacement but for the money spent you could build a better 3.6 turbo engine. A stock 3.6 will need as a minimum, lower compression pistons, rods reconditioned with aftermarket rod bolts, turbo scavenge pump, aftermarket fuel injection with bigger injectors, intercooler and turbo/exhaust system. This engine has the potential to make 450-500hp The stock 3.3 965 turbo is rated at 330hp (?) The suggested limit on the CIS injected turbo engines is 400-450HP. Starting with a 3.6 gives you more upside unless you can find a inexpensive used 3.3 turbo. The weak point for both engines is the cylinder to head junction. The 3.6 head does not lend itself to the Ni-resist modification as well as the early 3.0-3.3 cylinder head. Randy Aase has developed a "stepped" Ni-resist modification that can be used successively and some people weld up the side of the head with this modification, but I feel the earlier head is still a stronger configuration