As Travis and I work on his 36 Chevy I've been pondering the engine. We have a couple of core 305's to start with. Can you use 350 Vortec heads or is the small bore size, 3.736, to small for the valves to clear?
2.02 Valves are the problem w/ the small bore sbc's. If those 305's are under 2.02, you be fine and gain much-o power w/vortec's.
I would use the 305 heads. Some came with 1.84" intakes. I never understood why 305 heads with hardened valve seats are a recommended upgrade for 283s but no good on a 305. I like Vortec heads and run them on the 350 in my roadster. Using them on a 305 will most likely require a clearance notch in the block. This, combined with the slightly larger combustion chamber will lower the compression ratio. And don't forget to put a Vortec specific intake on the shopping list. If your plan is to buy new Vortec heads the formula changes. It costs no more to rebuild a 350 so you might as well start with a 350 if you can find one. A core will be $100-$200 and that is a cheap way to get 45 cubic inches. Several good threads here on building power in a 305.
305 roller w/L31 Vortecs is what im considering for my '41. Good power and Better mileage. https://sdparts.com/details/gm-performance-parts/12558060 Now a 3x2 is available for Vortecs too. http://www.jegs.com/i/Edelbrock/350/5417/10002/-1?parentProductId=746549#moreDetails
Unless they have been upgraded to 2.02, I think vortecs all have 1.94 intake as max size. The problem is that even if the 1.94 clear, the valve is so close to the wall that you get almost no flow on that portion. Which negates the benefits of the larger valve 1.94 vs the smaller 305 size. There was a company (Dart??) that made a special 305 head with the larger 1.94 valves, but they moved the valve centerlines closer together for exactly this reason. It helped move the valve away from the wall and unshrouded the flow in that area a bit.
I used the 416 heads on my 305.Either these or the 624 heads with a little work actualy work pretty good.Have them crack checked as the 624 were prone to cracking more than others.
Yes on the 1.940" intake valve size of the cast iron Vortec heads. The aftermarket heads you are thinking of are from World Performance SR Torquer 305 heads, not Dart, hope that helps, TR
If I remember correctly the SR 305 Torquer heads had relocated 2.020" intakes but with a 58 cc Combustion chamber. Maybe 170 cc on the intake runner. I'm not a expert on these Micro-Mouse Motors, although they could be used as a Pony Motor to start my big ones!
Will they work-yes, but I think you need to mill them .030 and use a shim gasket to save your compression ratio. A better option is to find a 350 or the (Forgotton Bast**d) chevy 307 with its 3.25 stroke and 3.875 bore keeps out of detonation, unlike the 305.
I like both versions of the SR, they respond very well to well thought out porting. An under-rated head with excellent mid lift flow potential.
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