Then I think you will likely be happier with a later model 250-292 or if you really want to do it, the Vortec 4200 as mentioned above. The 4200 is a tremendous motor but you will need to tinker quite a bit to sort out the install issues.

The 235, it's an old design, the head does not breath all that well, only four main bearings, cast steel crank but not all that strong, old style rocker shaft system. I love tinkering with the 235/261 motors but they are not for everyone. I don't think in this instance that you will be happy building one for what you want to do.