WARNING: If you are not a serious motor-head, you may want to avoid reading this post
Okay guys I have been researching the mild 427 build up for the 23' inboard project boat. Here are a few details. Realizing the 427 motor is already a fine marine design, I am not going to a crazy automotive stage here, as it would only toast the motor quickly and there is no point in doing that.
Therefore the build will be a mild tweak this first time around, thinking this is the safe thing to do and also thinking there is no need to go any further than 200 more horses than Chris Craft originally put into this hull. The original power for the 23' inboard Lancer was the 350Q which had a compression of 8.8:1, 235-hp at 4200 rpm, and weighed in at 964 pounds for the direct drive setup. The big dog weighs in at 1143 pounds with the same direct drive, but I am trimming off about 200 pounds so the balance and overall weight of the boat will be generally identical with NO weight premium for the big block.
The 23' inboard hull with 350Q weighs in at 3695 pounds, while the comparable 427 V-drive 23' Lancer Premiere/Custom Super Sport was 4200 and the 427 23 Commander V-drive was 4695. Therefore I am in the same league of 3695 pounds but with nearly twice the power of the original hull.
Compression will remain at 8.9:1, heads and rockers will remain stock, but the cam, intake, exhaust and carbs will be upgraded as the first step in speed for the 23 hull.
Limitations will be a 5000 rpm max engine speed. If the heads come off they will be re-used, perhaps in mildly ported form, as these are quite good Ford heads. Going to an aluminum Edelbrock would save weight, but would not appreciably gain all that much power. I like the iron heads. The intake alone will save half the weight of a small person (25 pounds versus 80 pounds for the iron manifold). Exhaust manifolds and risers will be all water jacketed cast aluminum racing NICSON type, which I already have. Therefore the overall weight of the motor with manifolds will be about 175 200 pounds lighter, perhaps a bit more due to the fact that those marine 427 iron exhaust manifolds and risers are VERY heavy.
Comp Cam grind 270S will be used, featuring an operating band of 1800 to 5500 RPM, part number 33-244-4, advertised duration 270 (actual 224 at .050) and lift .540, with 110 lobe separation angle.
This is getting somewhat close to the original PI (Police Interceptor) cam Ford used. It is noted that Holman Moody original c3az-aa at 228-228-114 was the original 427/410hp cam, so this Comp is a reasonable choice. Compression is not going to be altered so this will keep power (and related heat generated within the motor) within reason.
For the record, the Ford 270/290 duration, .481 lift cam, was the stock police interceptor grind, and this was tweaked a bit to Cobrajet specs ie.279/290 duration and .481 lift.
It has been recommended to go with a (205-215) with at least.500 lift and 110-112 degree lobe centers as an improvement to the so-called old tech CJ/GT/PI cams, so this is yet another reason I settled on the Comp 270S. Comp has a good reputation, and everyone I checked with said to avoid the next step up, which would be the 282S, as it was more cam than the motor would be able to use (236 at .050 and .571 lift).
Spring load with the Comp solid 270s is just under 300 pounds, and the unsupported end rockers on the Ford rocker shaft are supposed to be able to handle this. After all, Ford was selling this same rocker assembly on engines rated for 6,000 rpm. To be safe however, I am adding a set of aluminum rocker shaft end supports from Precision Oil Pumps, as a 100% assurance to any thought of failure here. These are quite affordable and would be easy to install.
I have the full closed cooling system, but am thinking that this one will be raw water cooled, primarily for weight control, and the fact that the closed systems seem to run a bit on the hot side. This decision has not been made yet, but will be soon.
I am not intending to build this as a "go fast boat", just a very nicely done classic Lancer 23 but with lots of power. The 427-powered 23' Commander and the similar 23' Lancer Premier/Custom Super Sport, as well as numerous Monte Carlo models sold in Italy by Herb Pocklington, all had the same general level of power so I don't think I'll be over-powering the hull. Power expectation from the mods noted will be under 400, probably in the 350 range realistically.
As this project unfolds over the next 12 months (or so) I'll be posting engine info and test run data, etc. Stay tuned.