The "Throw Away 318"

It's my opinion that the SB's were capable of making more HP per cubic inch with less work then the BB's could do. But as I have said before, HP is nothing more than a calculation based upon Torque at a given RPM. Take into account that back when Emissions came around in the early 70's, the output of the 440 was dropped under 300 factory while the output of the 360 stayed closer to what the BB was rated at when compared to the highest ratings of either. 360's always were close to what old 383's were at anytime There were more head casting option available for the SB's then for the BB's and even with what was out there for the BB's the power potential in them was not all that much different. At least with the SB's you could swap on a set of 318 heads on a 273 and see a noticeable boost in flow. Of course putting a set of 202 340 heads on a 273 was out. Putting them on 318 was marginal unless you were using the later heads with the 188 intakes. Some people used to install 392 hemi intake valve in the both the poly and LA SB heads on 18ers because they didn't require dangerous bore notching. You could put the 188's in the 18er heads and have better flow and response with the smaller ports and bigger valves. Math will tell this if you know how to use it. It's all about cross sectional area, in ports and around raised valves. There were the original 340 TA heads with the offset rockers but the heads still have the restricted ports of the standard heads. They could be modified to make use of the extra area for more flow but the flow wasn't all that much better. MOPAR heads of any app. needed to be designed the same way heads for any other engine, raise the floors and straighten out the ports. Enter HEMI's. If I could find an old poly head I would work with it. They used those in early Factory backed circles in the early 60's because it was all they had and they did well. The valve and rocker design gave decent results. There is enough block for stoking and they were thick enough to overbore and not over heat. If anyone has one I may be interested. MOPAR even had a dual quad intake out for it from the factory at one time.