I have a 85 bronco with 300 and a 4 speed, offenhauser intake, 500 holly, long tube headers, I'm building a new long block and wanting a honest opinion what to do for more power, I like the 300 but I have winsors intwo other trucks and want to keep the 300 if it make enough power

 

I have 5.14 gears and 37" bloggers so I'm looking for faster Erving under load

 

Just wanting to make it more powerful than mild 351w, or should I just put a winsor in it?

 

Making more HP than a 351W is not going to be easy, with an inline 6. More low end torque, on the other hand, is quite doable. Torque is the inline six's party favor.
A 300 will make great torque from as low as 1200 RPM, and peaks in the 2-2.5K range (depending on internals) but is done making power by 4-4.5K due to the restrictive nature on the head. That is actually a safety feature, as the stock bottom end is only good for about 5K. That ~4" stroke makes for a lot of mass flinging around inside the lower end.

If you want low end grunt, for climbing hills/rocks, it's hard to beat an inline 6 with a few internal mods. Bump the comp ratio into the low 9's, and a mild-ish cam, along with intake/exhaust improvements, and the 300 will give plenty of low end torque.

If you want higher RPM power, for mud bog type action, go with a V8. Much cheaper to build for this type of purpose, and a bit lighter at the same time.

 

I guess it really depends what you are going to be using it for. Is it a street truck? Trail rig? Mud racer? What kind of fuel do you want to run?


You've got a good list of mods already. To go from there you are looking at a compression bump, cam swap and head work.

This is where your intended use comes in. If it's a street truck that you want to run pump gas in. I'd suggest around a .5 point bump in compression, a Comp 260 or 268 cam and for head work I'd would concentrate on the bowl areas and possibly larger valves ( no bigger then 1.94" intake valves ) .


If you are talking a mud racer then you are talking a lot more compression and money.

Or another option is power adders: Super charger, turbo/s or nitrous. But with a supercharger or turbo/s you are looking at a lot of fabrication because there will be no bolt on kits for the 300.

A V8 is almost always going to be cheaper to build power. You have to decide if the 300 will produce enough to make you happy.

 

It's gonna be a 20% street! and 80% trail. What cam would be the best for building a broader power band? And what mods are best bang for buck on head work?

 

If you can live with some cam lope, with the gears you are running, I'd go with the Comp 268H. If you would prefer a smoother idle the Comp 260H would be your choice. The 268H will give more power.



If you are on a budget, you are going to see the most gains by focusing the port work to the bowl areas. Then get a good multi-angle valve job.