Like said; slam a bigger engine in there, maybe with Hi-Po log manifolds and never look back.
Look, I'm not slamming 273s or 318s; I've owned and driven them both.
Your vert is pushing 3200pounds loaded, so when you say 275/300 hp, what you are really saying is 3200/300=10.67 pounds per horsepower.
But what you mean is X pounds per cubic inch, at a certain specific power output.
So for 300hp on a 273 you are saying 1.1 hp per cube which is getting to be a pretty specific build.Whereas
a 318 would need only .94 hp per cube, and
a 360 only.83 hp per cube
All of these engines weigh about the same.
All of these will cost about the same in basic machining.
The 360 will be happy with large-port heads and support works. Heck,it already comes with the right heads.
Pistons for the 360 are cheap. It will cost you close to double for 273 pistons.
Heck the 360 will make 300hp with just a cam and bolt-ons; super cheap
But here's the thing;
300 hp from a 273 is not the same as 300hp from a 360.
Each of these can be built to make the same number for a little better than an instant at some point in the rpm band. So if you got a boat, fine prop it right, and go; 300 is 300.
But your vert is not a boat, and the engines have to operate at every rpm between stall and whatever rpm 300hp comes at,and beyond; and the bigger engine will make more power than the smaller both coming and going. So the bigger will make more average power over any given rpm range.
So the question is; why spend more money for the 273 to get less actual performance?
There are only two justifications;
1) you don't care about the cost, or
2) you just want the 273
I mean no one can argue against these.
