Hello together, I often read, that the early 308 carb cars have hotter cams, than the later cars. Is this a specific US-car thing or a legend? I just have read it again somewhere and compared my spare parts books. And have to realize, that the parts numbers are the same in the '76 Vetro GTB and in the '80 carb GTB/GTS book. So what are the facts about hotter early cams? Best Regards from Germany Martin
For all euro carbed (like the two you mentioned) = all cams the same For up to 1977 US carbed = same (but some ends different for air pump drive and/or dist drive IIRC) For 1978 and 1979 US carbed = detuned For all euro and all US 2Vi = detuned
Steve, Can one 'drop in' the hotter cams in a 2VI car, change to Euro ECUs* and use the hotter indexing numbers and then tune the K-Jet to work properly? Will that work? * - I have a set of Euro boxes.
Hey there Mark - I'd be nervous about the idea of just dropping in a pair of higher lift exhaust cams, if you might still have the original hollow sodium valves. Easy to imagine a scenario where the higher lift of the new hipo cam could result in the exhaust valve 'slamming' into the seat with a harder force than before, and thus potentially damaging the integrity of the 30+ year old valve stems! Cheers - DM
I've no experience with doing that, but I wouldn't be too hopeful. If using cats, the answer is "no" (as too much of the intake charge would "leak" into the exhaust stream at overlap and overheat the cats). Without cats, Newman has reported success using more aggressive cams on a BB512i: https://www.ferrarichat.com/forum/threads/injected-boxer-with-cams-and-other-goodies.586533/ but don't know the exact numbers he is using (i.e., if the duration has been expanded all the way to the euro carb 308 cam spec or somewhere in between). F probably was erring on the conservative side of things, as Newman suggested, but he'd accept having something like a slightly rougher idle for more grunt above 5000 RPM
Paul placed a set of 76 cams into my former US 79 carb GTB a few years ago which made a remarkable before and after difference in performance. The car didn't have cats.
In an effort to fine tune the engine, I believe that the carbs received a new jet setup, otherwise, nothing else was needed. This change in conjunction with a prior switch to a single distributor, non cat exhaust, Pertronix vs points really got the most out of the engine. Of all of the changes, the new cams made the most significant jump in performance though.
I have no idea about the USA camshafts, but I own one of the last Euro carbed cars produced and its camshafts look to be very aggressive and studied for top end power with the engine pushing hard from 5000 RPM to 7000+ RPM. Euro 308 GTB and GTS carbed cars all have the same camshaft during all the car production: from 1975 to 1980 included ciao
As an aside, there were also the more aggressive camshafts from the so-called "sprintpack" option, but I seem to recall that those who have tried engines fitted with these found almost undriveable... Rgds
If someone is dumb, it is certainly me, not you. This means "peaky" not "street comfortable": "nothing", no torque, no power below 5500 rpm, all power and torque in a very narrow band. No "drivability". Don't know if this is more clear? Rgds
I had Elgin Cams map the profile of my ‘75 US 308GT4 cams. They said the profile was the same as the 365GTB/4 which was not what they expected based on other 308 cams they had seen, suggesting Ferrari softened the profile at some point.
The 365GTB/4 and the 308 engines share some design features, bore and stroke for example. Cam profile wouldn't surprise me at all.
