Building a 355
they have smaller intake valves 1.84 vs. 1.95 for stock 350 heads. With the 305 heads depending on the casting# for closed chamber design they will
give you no less than 11.1 comp. with the flat-tops. Use 350 heads, the vortec head is good with minor work. I ran 186 castings for years, these were off of 1969 to about 1972 models. Both of these heads would give you around 10 to 10.25 to 1 comp. Thats about max for iron heads and pump gas. We ran a comp cams .480" 230@.050", torquer II intake with 2" open spacer and 650 dbl. pumper, headers and made close to 425 hp. You need a good set of roller rockers and screwin studs with guide plates. Stock rockers want cut it. If your budget will allow you can get find aluminum heads at a decent price and make more power.


