Several years ago I had the (very bad) idea to make some changes to my 308. The idea was to remove the 550 hp 3.0 liter V8 I had built and install a 550-600hp V12….which it turns out was much easier said than done.
I wanted the car to stay period correct which meant picking an engine that was available in 1984 so I got myself a 4.8 liter 400i engine…but that’s a 2 valve engine. My car is a 308 quatrovalve (4 valve) so it just seemed wrong to install a 2Vengine. The Testarossa came out in 1984 and had 4V heads, but that’s a flat 12. So I decided the “right” thing to do would be to force fit the TR heads onto the 400 block and then force fit that engine onto the 308 transaxles (which is also the oil pan BTW).
That was 3 years ago and after quite a list of set-backs and about 15-20 lbs of aluminum welding rod I think I’m getting close. All the “castings” fit together and I’ve started the finish machining.
There was a bit of scope creep along the way so it’s now a 5.5 liter, it’s got 12 ducatic 999 throttle bodies V with show injectors (if I have low power issues I left room for low mount injectors and can run a hi-low set-up) which meant raising the intake ports 20 degree to make everything fit in the tight 60 degree, billet cams (the 400 and TR had different firing orders so I need to make cams that fit the TR heads but had the 400 timing, oh and would work with the 400 timing chain instead of the TR timing belt). The exhaust is 12-4-2 SS headers flowing out a pair of 3” pipes. I’m thinking should make right around 800hp at 9000 rpm when it comes to life (hopefully) next year.
I’ve got an M800 with ignition expander for it so it will be sequential fuel with waste spark….unless I decide to add 12 more injectors then it will have 2 M800s I guess.