Marine 273 build

69 Cuda 440 said

That is one nice 'wave rider'.

The 273/235 HP Commando is really closer to 215 HP {true NHRA racing numbers}.

The 340 Camshaft will probably add {+15 HP}.

And the Intake and Holley {600 CFM} Carburetor will probably add another
solid {+15 HP}, especially above 3000 RPM's.

The Cylinder Heads, more of 'any little porting helps over no porting'.

Generally, even a 'general smoothing job', and matching the ports {gasket port match}
is worth an easy {+10 HP}.

Click to expand...

Are those numbers relative to some known quantity (stock automotive 273 maybe?)? We'd need to know the baseline configuration to base the changes on, right? Just curious if you were using the marine 273 with the lower compression 318 heads and unknown stock cam, or something else. Im not sure what the stock numbers (cam, hp, etc) were on the automotive 273.

Yep, CC's most famous model is the Ski Nautique- we have a few of those as well. Theres currently a 340 build underway for a pretty cool orange '72, actually... should be in the 310-320hp range, we're thinking. Should be fun, considering the stock 225hp 318 pushed the boat pretty well.

Im thinking a 273 with 250-275hp at or around 5000-5200 would make for a pretty good running 16' (1600lb) boat. Sounds like some mildly ported 302 heads with a LD4B and 340 cam should get me close? I'd probably try the stock (500cfm?) AFB, as well as a 450cfm Holley... though a 600cfm Holley or Edelbrock might be worth trying as well.

My bone stock 273... needs a bit of freshening up- just like the rest of the boat!