I have worked on SBC’s a little before and ready to build one for my YJ. I just don’t know how to plan out a proper build.

I got a SBC/trans/case. The guy had it in the frame still and fired it up for a moment so I could see it was decent. Got the whole mess cheap so it will be a good start for my YJ. The case is a 203, so that is for sale. I plan to use my NP208 I already have.

Turned out the SBC is a 305. I don’t want to hear any crap about go get a 350. It’s fine for what I’m building.

My plan:
Run on propane
High compression
Good torque
Not a race motor, doesn’t need to rev high

I want to get high compression for running pane. Like 12:1 I’m thinking.
Now, what will it take to get there? I want to get my block bored at least 0.030. I am looking into Vortec heads for it cause I read they will be better flow and little larger valves than my heads. Do I need to machine the heads for lower cc to get the comp ratio? Should the block get milled down? Do I need dome top pistons, or flats? What kind of cam is good for all this? I hear there are propane specific cams, but haven’t read anything on them yet. If I’m told I need a high lift cam then will regular Vortec heads work? They are only good for a limited lift right? I’m thinking about a Edelbrock Air gap intake.

I was told pane would be a loss of power, so I want to build the engine to perform well on it. I could just slap this engine back together and hit the trail, but where’s the fun in that? I want to at least modify some stuff.

I can’t go crazy with money, cause I don’t have much of it and there are other things that need done like a rebuild of the TH350 trans. If I can afford to do all this by mid Nov then I can get it done in time. I have to move in Dec and it will prob be stuck in storage for an unknown time. The YJ runs and drives now, so I won’t tear into it unless I can get this all done in time. Money drives the schedule, so the cheaper this build is the better.

I’m not changing engines, don’t want to hear how I should dump this and get a 350. This is fine for a little YJ and will have plenty of power for me.

All the stuff I can find online for building engines is about street performace and I want more low end power and could care less about the top end. I don’t drive my YJ above 50mph. It’s not street legal and just a trail rig.
They don’t talk about building the comp #’s I want to achieve, so it’s tough for me to know how to plan this build.

Thanks
All help is appreciated